Publications
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Andreas Schiller, Sandra Jenatsch, Balthasar Blülle, Miguel Angel Torre Cachafeiro, Firouzeh Ebadi, Nasim Kabir, Mostafa Othman, Christian Michael Wolff, Aïcha Hessler-Wyser, Christophe Ballif, Wolfgang Tress, and Beat Ruhstaller
The Journal of Physical Chemistry Letters, 15, 11252−11258.
DOI: 10.1021/acs.jpclett.4c02403
This research paper investigates the impact of illumination on ion conductivity in perovskite solar cells (PSCs), highlighting the complex interplay between ionic and electronic charge transport. Using drift-diffusion simulations to reproduce experimental impedance spectroscopy results, the authors discovered that the increase in capacitance observed at low frequencies under illumination is mainly caused by changes in electronic currents that emerge naturally as a consequence of the mixed electronic-ionic conduction in the perovskite. The simulations show how the changes in the alternating electronic currents occur due to the screening of the alternating electric field by oscillating ions within the active layer of the PSCs.
A key contribution of this study is the introduction of a novel characterization technique to detect the presence of photo-enhanced ion conductivity. This technique is based on analyzing the frequency shift of the capacitance onset at different illumination intensities. The researchers extracted the frequency at which the capacitance reaches a specific value between the plateaus at lower and higher frequencies. By plotting the difference in the extracted frequency at various illumination intensities compared to in the dark, they observed distinct qualitative differences in the frequency shift patterns, depending on the presence of a photoconductive effect on the ions.
The findings revealed that if there is no photoconductive effect, the derivative of the frequency shift decreases at lower illumination intensities. In contrast, in simulations mimicking a photoconductive effect, the derivatives increase with decreasing illumination intensity. To capture these distinct patterns, the technique requires a series of capacitance measurements over several orders of magnitude in illumination intensity. The illumination intensity range should be carefully chosen to observe both the constant derivative decrease and the change in the derivative at lower intensities.
The researchers successfully applied this method to four different PSCs with varying active materials, confirming the presence of photo-enhanced ion conductivity in all the devices. This novel technique offers a simple and effective way to detect photo-enhanced ion conductivity in PSCs. It utilizes impedance measurements on fully integrated devices, making it practical for real-world applications. By contributing to a better understanding of the complex interplay between ionic and electronic charge transport, this technique can ultimately lead to improved device performance and stability.
Fluxim's Setfos simulation software and Paios measurement platform were crucial to this research. Setfos enabled the creation of a drift-diffusion model of a PSC, simulating the behavior of the active layer—treated as a mixed electronic-ionic conductor—under different illumination conditions. This simulation was instrumental in understanding the influence of ionic charge carriers on capacitance and conductance. Paios, equipped with its calibrated white LED light source, was used to perform Electrochemical Impedance Spectroscopy (EIS) measurements on the PSCs to detect photoconductive effects on the ions.
These findings emphasize the need for further research to develop a complete understanding of the phenomenon, as the interaction between ionic and electronic charge transport plays a significant role in the performance and stability of PSCs.
Aeberhard, U., Natsch, N., Schneider, A., Zeder, S.J., Carrillo-Nuñez, H., Blülle, B. and Ruhstaller, B. (2024),
Sol. RRL 2400492.
https://doi.org/10.1002/solr.202400492
This research paper examines reverse-bias breakdown in all-perovskite tandem solar cells, particularly under partial shading conditions, and highlights how nonuniform active area quality, such as variations in mobile ion concentration, can impact their performance. The study uses a multi-scale simulation approach to demonstrate that an increase in mobile ion density significantly reduces the breakdown voltage and can lead to localized current hot spots in large-area modules. The authors suggest that these hot spots, caused by fluctuating mobile ion concentration, are potential degradation centers in the solar cells. They also suggest further investigation into factors like unintentional doping and additional breakdown mechanisms to better understand and improve the performance of these solar cells.
How SETFOS Was Used to Study Reverse-Bias Breakdown
The authors of the research paper use the device simulation tool SETFOS to perform cell-level simulations on all-perovskite tandem solar cells. Here's a breakdown of its role:
Drift-diffusion Simulation: SETFOS is used to simulate the behavior of charge carriers within the solar cell under a large reverse-bias voltage. This helps researchers visualize the band profile, or the energy levels of electrons within the device's various layers.
Mobile Ion Consideration: The simulations in SETFOS incorporate the effects of mobile ions within the perovskite layer, a crucial aspect that influences the breakdown voltage.
Coupling with Quantum Transport Simulation: The data from SETFOS, including the band profile and quasi-Fermi levels, are then used as input for a separate quantum transport simulation tool, PVnegf. This allows for a microscopic examination of the tunneling breakdown current.
Iterative Analysis: The tunnel generation rates, calculated in PVnegf, are fed back into SETFOS. This iterative process, with information exchanged between SETFOS and PVnegf, continues until the tunneling current converges, providing an accurate representation of the breakdown phenomenon.
Generating JV Curves: Through this coupled simulation approach, SETFOS ultimately helps generate current density-voltage (JV) curves for the all-perovskite tandem solar cell, even under reverse-bias conditions. These JV curves are essential for understanding how the device performs near its breakdown voltage.
In summary, SETFOS acts as the foundation for the cell-level simulations, providing crucial data about charge transport and mobile ion behavior, which is then combined with quantum transport calculations to comprehensively study reverse-bias breakdown in all-perovskite tandem solar cells.
Using Laoss to Simulate Large-Area Solar Module Behavior
The authors use Laoss, a large-area thin-film electronics modeling tool, to understand how the performance variations observed at the cell level translate to the behavior of a complete solar module12.
Here's a breakdown of its use:
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Quasi-3D Module Simulation: Laoss enables a "2D+1D" simulation approach, treating the top and bottom electrodes with a 2D finite element method (FEM) while using a 1D coupling law to represent the vertical current flow through the active area of the solar cells within the module3.
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Incorporating Cell-Level Data: The JV curves generated in SETFOS, which incorporate the effects of varying mobile ion densities and reverse-bias breakdown, are used as input for Laoss1. These curves act as the local 1D coupling law within the module simulation, linking the 2D electrode simulations3.
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Module Design and Interconnection: The researchers incorporate design parameters of a real all-perovskite tandem module into the Laoss simulation. These parameters, taken from a previously calibrated model4, include sheet resistances of electrodes, scribe line geometries for monolithic interconnection, and the Ohmic properties of the P2 scribe2.
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Spatial Resolution: Laoss simulates a 10 cm x 10 cm module with a spatial resolution of 3 x 30 pixels per cell stripe, totaling 900 pixels. Each pixel is randomly assigned a JV curve based on a Gaussian distribution of mobile ion concentrations, representing real-world variations in manufacturing2.
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Partial Shading Analysis: The study simulates both full and partial shading conditions on a single cell stripe within the module using Laoss5. This allows the authors to observe how variations in mobile ion density (and thus, breakdown voltage) at the pixel level affect current flow and hot spot formation under these conditions6.
In essence, Laoss allows the researchers to scale up their analysis from the behavior of individual solar cells to a complete module, taking into account the realistic variations in properties and the effects of partial shading. This multi-scale approach, linking the detailed device physics simulated in SETFOS to the module-level performance predicted by Laoss, provides a powerful tool for understanding and mitigating potential degradation mechanisms in all-perovskite tandem solar cells.
C.-H. Chen, M.-H. Yu, Y.-Y. Wang, Y.-C. Tseng, I. Chao, I. Ni, B.-H. Lin, Y.-J. Lu, C.-C. Chueh, Small 2024, 20, 2307774. https://doi.org/10.1002/smll.202307774
The research investigates the enhancement of 2D tin-based pure red perovskite light-emitting diodes (PeLEDs) using a dual-additive approach involving natural antioxidants and cyclic molecular additives. Specifically, ascorbic acid (VitC) is used to prevent the oxidation of Sn²⁺ to Sn⁴⁺ and improve film quality, while 18-Crown-6 is added to capture excess ions and synergistically reduce nonradiative recombination pathways. This combination significantly improves the PeLEDs' performance, achieving a maximum external quantum efficiency of 1.87%, which is approximately nine times higher than the pristine device. The study highlights the potential of environmentally friendly additives to enhance the stability and efficiency of Sn-based perovskite films for sustainable optoelectronic applications.
Use and Value of Paios
Paios, the all-in-one characterization tool from Fluxim, was employed for capacitance-voltage (C-V) measurements and transient electroluminescence (EL) decay measurements.
The C-V measurements provided insights into the charge injection and recombination processes in the PeLEDs, indicating that the 25CC film (with both VitC and 18-Crown-6) had the highest charge transfer efficiency and lowest trap density.
Transient EL measurements revealed that the 25CC devices had the fastest response time and lowest trap density, confirming the superior carrier mobility and performance
Raphael F. Moral, Carlo A. R. Perini*, Tim Kodalle, Ahyoung Kim, Finn Babbe, Nao Harada, Javid Hajhemati, Philip Schulz, Naomi S. Ginsberg, Shaul Aloni, Craig P. Schwartz, Juan-Pablo Correa-Baena*, and Carolin M. Sutter-Fella*
ACS Energy Lett. 2024, 9, 6, 2703–2716
Publication Date: May 14, 2024
https://doi.org/10.1021/acsenergylett.4c00728
This study investigates ionic dynamics at 2D/3D halide perovskite interfaces in solar cells, revealing that light and heat induce ion migration. Phenethylammonium halide salts enhance efficiency and stability, with specific migration patterns and phase distributions observed under thermal treatment, impacting photovoltaic performance.
How Litos Lite was used
The photovoltaic performance assessment was conducted utilizing a Fluxim Litos Lite arrangement, which featured a Wavelabs Sinus-70 AAA solar simulator that produced an AM1.5 spectrum for excitation purposes. The current−voltage (J−V) attributes were obtained through both forward and reverse scans, each performed at a scan rate of 50 mV s−1. Stabilized power output measurements were completed utilizing a maximum power point (MPP) tracking algorithm over a span of 60 s.
Hang Hu; An, Sophie X.; Li, Yang; Orooji, Seyedamir; Singh, Roja; Schackmar, Fabian; Laufer, Felix; Jin, Qihao; Feeney, Thomas; Diercks, Alexander; Gota, Fabrizio; Moghadamzadeh, Somayeh; Pan, Ting; Rienäcker, Michael; Peibst, Robby; Nejand, Bahram Abdollahi; Paetzold, Ulrich W.
Energy Environ. Sci.2024,17, 2800-2814.
In this paper Prof. Ulrich W. Paetzold's team at KIT achieved a record 24.4% efficiency in triple junction perovskite solar cells using a new vacuum-assisted growth process. The mid-subcell, made of FAPbI3, ensures thermal stability and ideal interfaces.
How Paios was used
The researchers used the PAIOS system for various measurements including electrical impedance spectroscopy, transient photovoltage, electroluminescence, photoluminescence imaging, Mott-Schottky, dark J–V curves, and space-charge-limited current, enabling efficient, streamlined analysis and characterization of their triple-junction perovskite solar cells .
Sami Toikkonen, G. Krishnamurthy Grandhi, Shaoyang Wang, Bora Baydin, Basheer Al-Anesi, L. Krishnan Jagadamma, Paola Vivo.
Adv Devices Instrum.2024;5:0048.
The study investigates the necessity of doping Spiro-OMeTAD in lead halide perovskite (LHP) indoor photovoltaics (IPVs). It concludes that undoped Spiro-OMeTAD can achieve high efficiency and stability under low-light conditions, rivaling doped counterparts, suggesting that dopants may not be essential for effective IPV performance.
How Litos Lite was used
Litos Lite was utilized to perform J–V reverse and forward sweeps (scan rate 50 mV s−1), maximum power point (MPP) tracking, and stable power output (SPO) measurements on the prepared photovoltaic cells. These measurements were conducted under both simulated sunlight (AM 1.5G, 1-Sun, 100 mW cm−2) and indoor WLED illumination (5,000 lux, ≈1.60 mW cm−2) in N2 atmosphere. The indoor MPP tracking was performed either under continuous illumination or in 8-hour light–16-hour dark cycles .
How Paios was used
Transient photovoltage and transient photocurrent measurement were carried out with the all-in-one characterization platform, Paios.
Othman, M., Jeangros, Q., Jacobs, D. A., Futscher, M. H., Zeiske, S., Armin, A., Jaffrès, A., Kuba, A. G., Chernyshov, D., Jenatsch, S., Züfle, S., Ruhstaller, B., Tabean, S., Wirtz, T., Eswara, S., Zhao, J., Savenije, T. J., Ballif, C., Wolff, C. M., & Hessler-Wyser, A. (2024). Energy & Environmental Science. The Royal Society of Chemistry.
DOI: https://doi.org/10.1039/D4EE00901K
This study investigates the effects of cationic alloying in cesium-formamidinium perovskite films on optoelectronic properties and solar cell performance. It finds that precise Cs+ tuning minimizes structural faults and enhances photoconductivity, with encapsulated devices maintaining 85% of initial efficiency after 1400 hours under continuous illumination, providing insights into defect tolerance and stability mechanisms in perovskite materials.
Fluxim's Research Tools
In the study, Fluxim's Paios system was used for conductivity measurements, and Litos for accelerated aging tests under thermal and photonic stress, evaluating the stability of perovskite solar cells.
Cachafeiro, Miguel A Torre, Naresh Kumar Kumawat, Feng Gao and Wolfgang Tress.
National Science Review (2024): nwae128
https://doi.org/10.1093/nsr/nwae128
The paper investigates the pulsed operation of perovskite LEDs (PeLEDs), focusing on the role of mobile ions in transient electroluminescence. Drift-diffusion simulations demonstrate how mobile ions affect the TrEL signals and device performance, with findings crucial for optimizing PeLED design and function.
How Setfos was used
The Setfos software was used to perform drift-diffusion simulations that modeled the behavior of mobile ions in perovskite LEDs. It analyzed their impact on transient electroluminescence and device performance, helping to elucidate the mechanisms affecting light emission during pulsed operation.
Almora, O., López-Varo, P., Escalante, R., Mohanraj, J., Marsal, L. F., Olthof, S., & Anta, J. A. (2024). arXiv:2402.00439 [physics.app-ph]
https://doi.org/10.48550/arXiv.2402.00439
The paper analyzes degradation in perovskite solar cells using impedance spectroscopy, focusing on NiOx passivation. It identifies how interface treatments influence device performance, with some treatments stabilizing and others inducing degradation. Simulation tools model transport properties to understand these effects.
How Setfos Was Used
Fluxim's Setfos simulation software was employed to model the transport properties and electrical responses of passivated-NiOx perovskite solar cells. This facilitated the understanding of how modifications at the hole transport layer-perovskite interface, due to various passivation methods, impact the cells' performance and operational stability.
Thiesbrummel, J., Shah, S., Gutierrez-Partida, E. et al.
Nat Energy (2024).
https://doi.org/10.1038/s41560-024-01487-w
The study reveals that the dominant factor in the degradation of perovskite solar cells (PSCs) under operational conditions is mobile ion-induced internal field screening, significantly reducing efficiency mainly due to current density reduction, without major bulk or interface quality degradation.
How Setfos was used
Setfos was used to simulate the impact of increasing mobile ion density on PSC performance, demonstrating that higher ion density leads to enhanced internal field screening, reducing charge extraction efficiency and contributing significantly to early degradation losses in PSCs.
C.-H. Chen, M.-H. Yu, Y.-Y. Wang, Y.-C. Tseng, I. Chao, I. Ni, B.-H. Lin, Y.-J. Lu, C.-C. Chueh,
Small 2024, 2307774.
https://doi.org/10.1002/smll.202307774
This paper presents a method to significantly enhance the performance of 2D tin-based red perovskite LEDs through the use of natural antioxidants and cyclic molecular additives, particularly ascorbic acid and 18-Crown-6. These additives mitigate the oxidation of Sn2+ to Sn4+ and improve film quality, leading to a substantial increase in external quantum efficiency (EQE), purer color, and better bias stability. The study showcases a potential dual-additive approach for advancing 2D Sn-based perovskite LEDs towards sustainability and efficiency.
How Paios was used
Paios was utilized for comprehensive electrical characterization, including space-charge-limited current measurements, electrochemical impedance spectroscopy, capacitance-voltage analysis, and transient electroluminescence studies. These tests revealed that the additives effectively reduced trap densities and leakage currents, improved carrier transport, and enhanced charge transfer efficiency, corroborating the additives' impact on device performance and stability.
Fangfang Yuan, Yuncai Liang, Zhipeng Miao, Ting Zhang, Rudai Zhao, Sihui Peng, Yunhang Xie, Wenlong Liang, He Zhu, Pengwei Li, Yiqiang Zhang, and Yanlin Song
Chemistry of Materials 2024 36 (3), 1621-1630
https://doi.org/10.1021/acs.chemmater.3c02960
This paper reports the development of highly efficient and stable 2D Dion-Jacobson perovskite solar cells using oxygen-containing diamine cations (OBEAI). These cations optimize charge transfer properties, leading to a power conversion efficiency (PCE) of up to 18.81% and outstanding stability, maintaining over 90% of initial performance after 2000 hours.
How Paios was used
Paios was used to assess the charge transport and recombination dynamics in perovskite films, highlighting improved electron transport, reduced recombination, and enhanced charge collection efficiency after OBEAI modification.
Zheng Zhang, Jiaqi Liu, Huan Bi, Liang Wang, Qing Shen, Shuzi Hayase,
Chemical Engineering Journal, Volume 483, 2024, 149345, ISSN 1385-8947,
https://doi.org/10.1016/j.cej.2024.149345.
This study achieved over 14% efficiency in highly reproducible Sn perovskite solar cells by utilizing polysilanes, particularly polymethyl-phenyl-silane (PMPS), for defect passivation and morphology improvement. The application of PMPS enhanced surface quality, grain size, and reduced Sn4+ defects, leading to significant improvements in device efficiency and stability.
How Paios was used
Paios was used to evaluate charge transport and recombination dynamics, providing insights into the improved photovoltaic performance through enhanced electron transport, reduced recombination, and increased charge collection efficiency.
Zbinden, O., Knapp, E. and Tress, W. (2024), Sol. RRL 2300999.
https://doi.org/10.1002/solr.202300999
his study demonstrates how machine learning (ML) can pinpoint the parameters limiting efficiency in perovskite solar cells (PSCs) by analyzing current density–voltage curves from simulated devices. Over 11,000 simulated curves, varying 20 physical parameters related to charge transport and recombination, trained ML models to classify limiting parameters with over 80% accuracy. Random Forests showed the best performance, identifying key parameters like short-circuit current density, open-circuit voltage, and fill factor as critical for predictions. Applied to real device data, the model accurately identified efficiency-limiting factors, validating the approach's utility in guiding performance improvements and understanding device behavior, particularly during degradation. This methodology promises significant time and resource savings by reducing trial-and-error in PSC optimization.
How Setfos was Used
Setfos was used to generate about 11,150 current density–voltage (J–V) curves for perovskite solar cells by systematically varying one device parameter at a time, facilitating the training of machine learning algorithms to identify performance-limiting parameters based on these simulations.
Valastro, S., Calogero, G., Smecca, E., Bongiorno, C., Arena, V., Mannino, G., Deretzis, I., Fisicaro, G., La Magna, A. and Alberti, A. (2024), Sol. RRL 2300944.
https://doi.org/10.1002/solr.202300944
The research demonstrates printable carbon-based perovskite solar cells infiltrated with CsPbI3:EuCl3 outperform AVA-MAPbI3 cells, showcasing reduced hysteresis, stable efficiency under continuous light, and notable durability with multiple reusability cycles. Achieving a peak power conversion efficiency of 16.72%, the CsPbI3:EuCl3 variant emerges as a promising candidate for sustainable and efficient photovoltaic technologies, with implications for enhancing the environmental sustainability of solar energy generation
How Setfos was used
Setfos tool was utilized for 1D transient-mode electro-optical simulations of the fabricated mesoporous carbon perovskite solar cells (mC-PSCs), incorporating both anion and cation migration within the active regions. This involved simulating the charge generation profile using the transfer-matrix method, calibrated with wavelength-dependent complex refractive indices of all layers, and coupling it with a drift-diffusion charge transport solver to account for charge trapping, recombination, and ion migration. The simulations aimed to replicate the measured J–V curves' main features, with layer-specific electrical parameters calibrated based on reasonable initial values from literature.
C.-H. Chen, M.-H. Yu, Y.-Y. Wang, Y.-C. Tseng, I. Chao, I. Ni, B.-H. Lin, Y.-J. Lu, C.-C. Chueh,
Small 2024, 2307774.
https://doi.org/10.1002/smll.202307774
This research explores the use of natural antioxidants as additives to improve the fabrication of environmentally friendly Sn-based perovskite films, tackling oxidation and crystallization challenges. Ascorbic acid is highlighted for its effectiveness against oxidation, and when combined with 18-Crown-6, it enhances 2D red Sn-based PeLED performance, increasing efficiency, color purity, and stability, showcasing a sustainable dual-additive approach for optoelectronic applications.
How Paios was used
Impedance and TEL to demonstrate better transport with additives.
Nguyen, H., Penukula, S., Mahaffey, M. et al. MRS Communications (2024).
https://doi.org/10.1557/s43579-023-00510-7
This study investigates how polyvinylpyrrolidone (PVP) affects cesium-based lead halide perovskites, focusing on phase, morphology, film stress, and ion concentration during aging. Using PVP in CsPbI3 enhances film stability by inducing compressive stress, with negligible impact on bandgap and ion behavior under aging conditions.
How Paios was used
The all in one characterization tooll, Paios, was used to analyse ion concentration with transient current measurements.
S. Ravishankar, L. Kruppa, S. Jenatsch, G. Yan and Y. Wang, Energy Environ. Sci., 2024,
The paper discusses a novel method for analyzing solar cell operation, focusing on perovskite solar cells (PSCs). It addresses a gap in understanding the equivalence of time-domain and frequency-domain data in solar cell analysis. The study introduces a new approach to extract a previously inaccessible time constant from frequency domain data, which correlates with charge extraction speed in transient measurements. This method is validated through simulations and experimental data, offering a more comprehensive understanding of charge carrier dynamics in solar cells, particularly regarding charge collection efficiency.
How Setfos was used
SETFOS was utilized in the paper for conducting drift-diffusion simulations. These simulations were part of the study's methodology to characterize perovskite solar cells (PSCs) using various techniques, including transient photovoltage (TPV), transient photocurrent (TPC), intensity-modulated photovoltage spectroscopy (IMVS), intensity-modulated photocurrent spectroscopy (IMPS), and impedance spectroscopy (IS)
Lei Gao, Helin Wang, Qiang Guo, Zongtao Wang, Fan Yuan, Erjun Zhou,
Chemical Engineering Journal, Volume 480, 2024, 148277, ISSN 1385-8947,
https://doi.org/10.1016/j.cej.2023.148277.
The paper presents a novel D-A-D typed fused-ring perylene diimide (PDI)-based organic small molecule, PDTI1, as a cathode interface layer (CIL) for efficient inverted perovskite solar cells (PSCs). PDTI1 enhances electron transport, improves power conversion efficiency (PCE) to 24.64%, and offers better stability compared to control devices. This work demonstrates PDTI1's superiority as a CIL, providing an alternative for high-efficiency PSCs.
How Paios was used
Paios was used in the study for conducting two key tests: Transient Photocurrent (TPC) and Transient Photovoltage (TPV). These tests were performed in the dark to analyze the characteristics of the solar cells.
Sota Kikuchi, Takayuki Okamoto, Mengmeng Chen, Shen Qing, Shuzi Hayase,
Next Materials, Volume 3, 2024, 100098, ISSN 2949-8228,
https://doi.org/10.1016/j.nxmate.2023.100098.
The paper presents a study on improving the efficiency of lead-free ASnI2Br perovskite solar cells using phenyltrihydrosilane (PhSiH3) passivation. This passivation effectively reduces Sn4+ and creates a hydrophobic surface, enhancing the solar cells' efficiency from 3.65% to 5.50%. The process involves passivating the film surface with PhSiH3 solution, which decreases Sn4+ concentration on the perovskite film surface and makes the surface hydrophobic, resulting in better contacts with the C60 layer. The study demonstrates the effectiveness of PhSiH3 treatment in enhancing solar cell performance.
How Paios was used
Paios was utilized specifically for impedance measurement and analysis. This all-in-one characterization tool helped the researchers in assessing the electrical properties of the perovskite solar cells, which is crucial for understanding and enhancing their performance.
hunyan Lu, Xiaodong Li, Haobo Yuan, Wenxiao Zhang, Xuemin Guo, Acan Liu, Hui Yang, Wen Li, Zhengbo Cui, YuYang Hu, Junfeng Fang,
Chemical Engineering Journal, Volume 480, 2024, 147267, ISSN 1385-8947,
https://doi.org/10.1016/j.cej.2023.147267
The paper introduces a back-surface field in inverted CsPbI3 perovskite solar cells using 4-Imidazoleethylamine (4-IEA) treatment to improve efficiency and stability. The treatment upshifts the Fermi level at the CsPbI3 surface, creating an extra back-surface field that aligns with the built-in potential of the solar cells. This alignment reduces energy loss and facilitates electron extraction at the CsPbI3/electron transporting layer interface. Additionally, 4-IEA passivates interfacial defects due to its Lewis base-acid interaction with CsPbI3. The result is a power conversion efficiency of 20.22% and good operational stability, retaining over 70% efficiency after 200 hours at 65℃.
How Paios was used
Paios was employed for transient photocurrent decay (TPC) and transient photovoltage (TPV) decay measurements. These measurements were crucial in understanding the dynamic charge transport process in the solar cells. The TPC and TPV results demonstrated a significant reduction in non-radiative recombination and improved charge transport efficiency in the cells treated with 4-IEA, contributing to the overall improved performance of the solar cells.
Munkhtuul Gantumur et al 2024 Jpn. J. Appl. Phys. 63 015501
The study in "Japanese Journal of Applied Physics" by Munkhtuul Gantumur et al. explores the use of vacuum-deposited PbI2 to enhance the quality of perovskite films in solar cells. This method significantly improves the film's quality compared to spin-coated PbI2, leading to higher power conversion efficiency and better thermal stability in perovskite solar cells. Vacuum-deposited PbI2 results in uniform, pinhole-free films, facilitating efficient intercalation of MAI and the formation of high-quality MAPbI3 perovskite layers. This method also reduces ion migration, contributing to the improved performance and stability of the solar cells.
How Paios was used
Paios was used for electrochemical impedance spectroscopy (EIS) to examine the perovskite solar cells (PSCs). This technique provided insights into the electrical properties of the cells, such as resistance and capacitance, which are crucial for understanding and improving their performance.
Elkhouly, K., Goldberg, I., Zhang, X. et al.
Nat. Photon. (2024).
https://doi.org/10.1038/s41566-023-01341-7
Imec's research, published in Nature Photonics, details the creation of a perovskite LED stack that dramatically outshines conventional OLEDs.
The team used Setfos to analyze and optimize the light interactions within the perovskite structure. This approach significantly enhanced the LED's brightness and efficiency. The breakthrough paves the way for high-intensity, thin-film perovskite lasers with potential applications in medical diagnostics, environmental sensing, and advanced imaging, heralding a new era in optoelectronic devices. Setfos was instrumental in achieving the precise architecture needed for this revolutionary leap in light-emitting technology.
Md. Abdul Karim, Kiyoto Matsuishi, Md. Emrul Kayesh, Yulu He, and Ashraful Islam
ACS Applied Materials & Interfaces 2023 15 (39), 45823-45833
This paper discusses the improvement of FASnI3 perovskite solar cells' reproducibility and stability by incorporating 4F-PHCl, a reductive molecule, in the perovskite precursor solution. 4F-PHCl enhances the solution's stability, prevents Sn2+ oxidation, and improves the films' crystallinity and stoichiometry, resulting in a power conversion efficiency of 10.86%.
How Paios was used
PAIOS was used to measure transient photovoltage and photocurrent decays, shedding light on charge carrier dynamics and demonstrating improved charge transport and reduced recombination in 4F-PHCl-treated devices.
Xin Zhang, Stijn Eurelings, Andrea Bracesco, Wenya Song, Stijn Lenaers, Wouter Van Gompel, Anurag Krishna, Tom Aernouts, Laurence Lutsen, Dirk Vanderzande, Mariadriana Creatore, Yiqiang Zhan, Yinghuan Kuang, and Jef Poortmans
ACS Applied Materials & Interfaces 2023 15 (40), 46803-46811
This paper investigates enhancing perovskite solar cells' efficiency and stability using bi-TPAI surface modulation. It significantly improves power conversion efficiency and operational stability by passivating surface defects and facilitating charge extraction.
How Paios was used
Paios was employed for transient photocurrent and photovoltage measurements, revealing optimized charge dynamics and reduced recombination, which contribute to the observed performance improvements.
H. Bi, J. Liu, Z. Zhang, L. Wang, G. Kapil, Y. Wei, A. Kumar Baranwal, S. Razey Sahamir, Y. Sanehira, D. Wang, Y. Yang, T. Kitamura, R. Beresneviciute, S. Grigalevicius, Q. Shen, S. Hayase, Adv. Sci. 2023, 10, 2304790. https://doi.org/10.1002/advs.202304790
This paper investigates enhancing the efficiency and stability of MA-free perovskite solar cells using a ferrocene derivative (DBzFe) additive. The additive improves film quality, passivates defects, and inhibits ion migration, achieving a high power conversion efficiency of 23.53%.
How Paios was used
Paios was utilized for Mott-Schottky analysis and temperature-dependent c-f curves, providing insights into charge carrier dynamics, energy barriers for ion migration, and the benefits of DBzFe in improving device performance and stability.
G. Yu, Y. Huang, D. Khan, Y. Sui, S. Wang, X. Yang, W. Zhou, K. Chang, J. Tang, W. Chen, P. Han, Z. Tang, Small 2023, 2307219. https://doi.org/10.1002/smll.202307219
The paper explores the impact of embedding RbPbI3 seeds in PbI2 substrates to tailor the facet orientation and crystallization kinetics of perovskites, improving the performance and durability of perovskite solar cells.
How Paios was used
Paios was used for electrochemical impedance spectroscopy, revealing enhanced carrier dynamics and reduced non-radiative recombination in seed-processed films, contributing to the cells' high efficiency and long-term stability.
Sasiphapa Rodbuntum, Nuttaya Sukgorn, Narong Chanlek, Hideki Nakajima, Nopporn Rujisamphan, Pipat Ruankham, Duangmanee Wongratanaphisan, Anusit Kaewprajak, and Pisist Kumnorkaew
ACS Applied Energy Materials 2023 6 (20), 10364-10375
The paper addresses enhancing perovskite solar cells' performance and stability using a dual interfacial tin-oxide layer with chloride salt. It achieved a high power conversion efficiency and remarkable operational stability over 2400 hours.
How Paios was used
Paios was utilized for electrical and optical characterization, particularly for electrical impedance spectroscopy and intensity-modulated photocurrent spectroscopy measurements, providing insights into charge transport and recombination dynamics at the device interfaces.
Li, Z., Chen, Z., Shi, Z. et al. Nat Commun 14, 6441 (2023). https://doi.org/10.1038/s41467-023-41929-9
This paper focuses on enhancing the performance and response speed of perovskite light-emitting diodes (PeLEDs) by engineering the charge injection at the organic-inorganic heterointerfaces. They introduced a self-assembled monolayer to improve interface robustness, passivate interfacial traps, and align energy levels.
How Paios was used
Paios was used to study the transient photo-voltage and photocurrent responses, revealing improved charge injection and transport properties, which significantly enhanced the device's efficiency and response speed.
Q. Wang, H. Zhu, Y. Tan, J. Hao, T. Ye, H. Tang, Z. Wang, J. Ma, J. Sun, T. Zhang, F. Zheng, W. Zhang, H. W. Choi, W. C. H. Choy, D. Wu, X. W. Sun, K. Wang. Adv. Mater. 2023, 2305604.
https://doi.org/10.1002/adma.202305604
The paper demonstrates a spin quantum dot light-emitting diode (spin-QLED) using 2D chiral perovskite as a spin injection layer based on the chiral-induced spin selectivity (CISS) effect, enabling spin-dependent carrier transport. It operates at room temperature and zero magnetic field, achieving circularly polarized electroluminescence (CP-EL) with an asymmetric factor of 1.6 × 10^-2. The work highlights the potential of chiral materials in spintronics and quantum-based devices.
How Setfos was used
Setfos simulation was used to analyze the recombination center and carrier recombination rate distribution in the device, providing insights into the performance and guiding future improvements.
K. D. G. I. Jayawardena, R. M. I. Bandara, M. Monti,b E. Butler-Caddle,b T. Pichler, H. Shiozawa, Z. Wang, S. Jenatsch, S. J. Hinder, M. G. Masteghin, M. Patel, H. M. Thirimanne, W. Zhang, R. A. Sporea, J. Lloyd-Hughes and S. R. P. Silva
J. Mater. Chem. A 2020
https://doi.org/10.1039/C9TA10543C
The performance of all solar cells is dictated by charge recombination. A closer to ideal recombination dynamics results in improved performances, with fill factors approaching the limits based on Shockley–Queisser analysis. It is well known that for emerging solar materials such as perovskites, there are several challenges that need to be overcome to achieve high fill factors, particularly for large-area lead-tin mixed perovskite solar cells. Here we demonstrate a strategy towards achieving fill factors above 80% through post-treatment of a lead-tin mixed perovskite absorber with guanidinium bromide for devices with an active area of 0.43 cm2. This bromide post-treatment results in a more favorable band alignment at the anode and cathode interfaces, enabling better bipolar extraction. The resulting devices demonstrate an exceptional fill factor of 83%, approaching the Shockley–Queisser limit, resulting in a power conversion efficiency of 14.4% for large-area devices.
Michele De Bastiani, Erkan Aydin, Thomas Allen, Daniel Walter, Andreas Fell, Jun Peng, Nicola Gasparini, Joel Troughton, Derya Baran, Klaus Weber, Thomas P. White, and Stefaan De Wolf
Advanced Electronic Materials 2018, 1800500
https://doi.org/10.1002/aelm.201800500
Abstract: Charge accumulation at the electron and hole transport layers generates anomalous electrical behavior in perovskite solar cells (PSCs). Hysteresis in the current voltage characteristic and recombination at the interfaces are the clearest manifestations of this phenomenon, which compromises device performance and stability. Here, the underlying charge-carrier dynamics of a variety of PSCs are investigated by analyzing their transient photocurrent response. Towards shorter time scales, PSCs often show increasingly severe hysteretic responses. This phenomenon is correlated with the presence of interfacial accumulated charges that hinders the photogenerated carrier extraction process. However, introducing passivating contacts improves the carrier-injection properties and the devices become completely hysteresis free. These results underline the importance of contact passivation for PSCs and the need to further develop new passivating interlayers that simultaneously eliminate charge-carrier recombination and provide selective transport for each carrier type at the PSC’s contacts.
Francisco Peña-Camargo, Jarla Thiesbrummel, Hannes Hempel, Artem Musiienko, Vincent M. Le Corre, Jonas Diekmann, Jonathan Warby, Thomas Unold, Felix Lang, Dieter Neher, Martin Stolterfoht;
Applied Physics Reviews 1 June 2022; 9 (2): 021409. 86
https://doi.org/10.1063/5.00852
This scientific article presents a multifaceted approach to determine the electronic doping density in metal-halide perovskite systems. The researchers used various optical and electrical characterization techniques to quantify the doping density. The results showed that the doping density in perovskite thin films is below the critical threshold that would affect device performance. The doping-induced charges were found to be too low to redistribute the built-in voltage in the perovskite active layer. However, the presence of mobile ions in sufficient quantities was observed, which could create space-charge regions in the active layer. The experimental results were supported by drift-diffusion simulations. The findings suggest that perovskite thin films behave as intrinsic semiconductors and that doping does not significantly influence the performance of devices based on these materials.
How was Setfos used
Setfos was used to check that findings for doping also holds for mobile ions.
Zhenchao Li, Ziming Chen, Yongchao Yang, Qifan Xue, Hin-Lap Yip and Yong Cao
Nature Communications 10:1027 (2019)
https://doi.org/10.1038/s41467-019-09011-5
Abstract:
In recent years, substantial progress has been made in developing perovskite light-emitting diodes with near-infrared, red and green emissions and over 20% external quantum efficiency. However, the development of perovskite light-emitting diodes with blue emission remains a great challenge, which retards further development of full-color displays and white-light illumination based on perovskite emissive materials. Here, firstly, through composition and dimensional engineering, we prepare quasi-two-dimensional perovskite thin films with improved blue emission, taking advantages of reduced trap density and enhanced photoluminescence quantum yield. Secondly, we find a vertically non-uniform distribution of perovskite crystals in the PEDOT:PSS/perovskite hybrid film. Through modulating the position of the recombination zone, we activate the majority of quasi-two-dimensional perovskite crystals, and thus demonstrate the most efficient blue perovskite light-emitting diode to date with emission peak at 480 nm, record luminance of 3780 cd m−2 and record external quantum efficiency of 5.7%.
Jelena Vujančević, Pavao Andričević, Anđelika Bjelajac, Veljko Đokić, Maja Popović, Zlatko Rakočević, Endre Horváth, Márton Kollár, Bálint Náfrádi, Andreas Schiller, Kondrad Domanski, László Forró, Vera Pavlović, Đorđe Janaćković
Ceramics International 45,10013 (2019)
https://doi.org/10.1016/j.ceramint.2019.02.045
Abstract:
Highly ordered, anodically grown TiO2 nanotubes on titanium supports were annealed in ammonia atmosphere in order to incorporate nitrogen doping (. 2 at.%) in the titanium oxide lattice. FESEM micrographs revealed nanotubes with an average outer diameter of 101.5 ± 1.5 nm and an average wall thickness of about 13 nm. Anatase crystals were formed inside the tubes after annealing in ammonia atmosphere for 30 min. With further annealing, rutile peaks appeared due to the thermal oxidation of the foil and rise as the duration of heat treatment was increased. The concentration and chemical nature of nitrogen in the nanotube arrays can be correlated to the optical response of dry-pressed heterojunctions of doped TiO2/CH3NH3PbI3 single crystals. The N-TiO2/perovskite heterojunction with the highest amount of interstitial nitrogen exhibited an improved photocurrent, indicating the importance of the semiconductor doping-based heterojunction optimization strategies to deliver competitive levels of halide perovskite-based optoelectronic devices to be envisioned for urban infrastructures.
Meiyue Liu, Ziming Chen, Zhen Chen, Hin-lap Yip and Yong Cao
Mater. Chem. Front., 2019
https://doi.org/10.1039/C8QM00620B
Abstract:
The tandem architecture for perovskite solar cells has proven successful in promoting the development of such cells. A low-bandgap perovskite solar cell, which typically acts as a back cell, is one of the critical components for tandem perovskite solar cells. However, nowadays, highly efficient low-bandgap perovskite solar cells are mostly based on the inverted structure, which restricts the development of conventional perovskite tandem cells. Therefore, efficient low-bandgap perovskite solar cells based on the conventional structure need to be developed to further extend the availability of device architectures and interfacial materials for tandem cells. Here, by modifying the electron transport materials, we successfully demonstrated an efficient low-bandgap perovskite solar cell based on conventional structure. A ZnO/SnO2/C60-SAM tri-layer was used to engineer the energy level alignment of electron transport layers to reduce the energy loss occurring at the interface and simultaneously suppress the interfacial recombination and improve the charge extraction, resulting in a reduced open-circuit voltage loss for the device. Finally, our low-bandgap perovskite solar cells achieved a power conversion efficiency of 13.8%, which is the record result for conventional device structures to date.
S. Altazin, L. Stepanova, J. Werner, B. Niesen, C. Ballif, and B. Ruhstaller
Optics Express 26, A579 (2018)
https://doi.org/10.1364/OE.26.00A579
Abstract:We present an optical model implemented in the commercial software SETFOS 4.6 for simulating perovskite/silicon monolithic tandem solar cells that exploit light scattering structures. In a first step we validate the model with experimental data of tandem solar cells that either use front- or rear-side textures and extract the internal quantum efficiency of the methyl-ammonium lead iodide (MALI) perovskite sub-cell. In a next step, the software is used to investigate the potential of different device architectures featuring a monolithic integration between the perovskite and silicon sub-cells and exploiting rear- as well as front-side textures for improved light harvesting. We find that, considering the available contact materials, the p-i-n solar cell architecture is the most promising with respect to achievable photocurrent for both flat and textured wafers. Finally, cesium-formamidinium-based perovskite materials with several bandgaps were synthetized, optically characterized and their potential in a tandem device was quantified by simulations. For the simulated layer stack and among the tested materials with bandgaps of 1.7 and 1.6 eV, the one with 1.6 eV bandgap was found to be the most promising, with a potential of reaching a power conversion efficiency of 31%. In order to achieve higher efficiencies using higher band-gap materials, parasitic absorptance in the blue spectral range should be further reduced.
Kai-Ming Chiang, Bo-Wei Hsu, Yi-An Chang, Lin Yang, Wei-Lun Tsai, and Hao-Wu Lin
ACS Applied Materials & Interfaces 9, 40516 (2017)
https://doi.org/10.1021/acsami.7b12805
Abstract:In this work, a sequential vacuum deposition process of bright, highly crystalline, and smooth methylammonium lead bromide and phenethylammonium lead bromide perovskite thin films are investigated and the first vacuum-deposited organometallic halide perovskite light-emitting devices (PeLEDs) are demonstrated. Exceptionally low refractive indices and extinction coefficients in the emission wavelength range are obtained for these films, which contributed to a high light out-coupling efficiency of the PeLEDs. By utilizing these perovskite thin films as emission layers, the vacuum-deposited PeLEDs exhibit a very narrow saturated green electroluminescence at 531 nm, with a spectral full width at half-maximum bandwidth of 18.6 nm, a promising brightness of up to 6200 cd/m2, a current efficiency of 1.3 cd/A, and an external quantum efficiency of 0.36%.
Takeshi Gotanda, Shigehiko Mori, Haruhi Oooka, Hyangmi Jung, Hideyuki Nakao, Kenji Todori, and Yutaka Nakai
Journal of Materials Research 32,2700 (2017)
Abstract:
Perovskite solar cells are promising for realizing high power conversion efficiency (PCE) with low manufacturing costs, but efficient coating methods are needed for commercialization. Here, a gas blowing method was used to fabricate perovskite solar cells and was found to create a smooth perovskite layer and to prevent voids in large-area cells, when organic materials were used as scaffolds for forming the perovskite. A PCE of 13% in a 1 cm2 active area is achieved by tuning the band-gap energy of MAPbX3 via substitution of Br for I ions in X sites. Incorporation of a poly(3,4-ethylenedioxythiophene) hole transport layer with a higher work function increased the open circuit voltage of the solar cells. All layers of the cells were fabricated at low temperatures (,140 °C), which makes it possible to incorporate a polymer substrate for producing flexible solar cells and high-throughput fabrication.
Martin Thomas Neukom, Simon Züfle, Evelyne Knapp, Mohammed Makha, Roland Hany, Beat Ruhstaller
Solar Energy Materials and Solar Cells 169 (2017) 159–166
https://doi.org/10.1016/j.solmat.2017.05.021
Abstract:There is increasing evidence that the presence of mobile ions in perovskite solar cells can cause a current-voltage curve hysteresis. However, it is still the subject of ongoing debates on how exactly mobile ions influence the device operation. We use drift-diffusion simulations incorporating mobile ions to describe IV curves of preconditioned methylammonium lead iodide perovskite solar cells and compare them with experimental results. Our simulation results show that the hysteresis depends on the extent of surface recombination and on the diffusion length of charge carriers. We provide a detailed explanation for the reduced hysteresis of perovskite solar cells with high power conversion efficiencies. We find that in high-efficiency solar cells ion migration is still present, but does not cause a hysteresis effect. In these devices, charge extraction is mainly driven by the diffusion of free electrons and holes.
Martin Neukom,
Msc Thesis, Jan 2016.arXiv:1611.06425 [cond-mat.mtrl-sci]download PDF
Abstract:Transient opto-electrical measurements of methylammonium lead iodide (MALI) perovskite solar cells (PSCs) are performed and analyzed in order to elucidate the operating mechanisms. The current response to a light pulse or voltage pulse shows an extraordinarily broad dynamic range covering 9 orders of magnitude in time – from microseconds to minutes – until steady-state is reached. Evidence of a slowly changing charge density at the perovskite layer boundaries is found, which is most probably caused by mobile ions.
Currentvoltage curves (IV curves) are measured with very fast scan-rate after keeping the cell for several seconds at a constant voltage as proposed by Tress et al. Numerical drift-diffusion simulations reproduce the measured IV curves using different distributions of ions in the model. Analysing the band diagram of the simulation result sheds light on the operating mechanism.
To further investigate the effects at short time scales (below milliseconds) photo-generated charge extraction by linearly increasing voltage (photo-CELIV) experiments are performed. We postulate that mobility imbalance in combination with deep hole trapping leads to dynamic doping causing effects from microseconds to milliseconds. Comprehensive transient drift-diffusion simulations of the photo-CELIV experiments strengthen this hypothesis.
This advanced characterization approach combining dynamic response measurements and numerical simulations represents a key step on the way to a comprehensive understanding of device working mechanisms in emerging perovskite solar cells.
Sudhir Kumar, Jakub Jagielski, Tommaso Marcato, Simon F. Solari, and Chih-Jen Shih
J. Phys. Chem. Lett. 2019, 10, 24, 7560-7567
https://doi.org/10.1021/acs.jpclett.9b02950
There has been a tremendous amount of interest in developing high-efficiency light-emitting diodes (LEDs) based on colloidal nanocrystals (NCs) of hybrid lead halide perovskites. Here, we systematically investigate the ligand effects on EL characteristics by tuning the hydrophobicity of primary alkylamine ligands used in NC synthesis. By increasing the ligand hydrophobicity, we find (i) a reduced NC size that induces a higher degree of quantum confinement, (ii) a shortened exciton lifetime that increases the photoluminescence quantum yield, (iii) a lowering of refractive index that increases the light outcoupling efficiency, and (iv) an increased thin-film resistivity. Accordingly, ligand engineering allows us to demonstrate high-performance green LEDs exhibiting a maximum external quantum efficiency up to 16.2%. The device operational lifetime, defined by the time lasted when the device luminance reduces to 85% of its initial value, LT85, reaches 243 min at an initial luminance of 516 cd m–2.
Martin T. Neukom
Dissertation, University of Augsburg, 2019
Solar energy is one of the key enabling technologies for the transition to a zero-carbon society – a necessity to mitigate global climate change. Emerging photovoltaic technologies based on novel semiconductor materials offer new disruptive applications since they can be made light-weight, flexible and in arbitrary shape and colour. A novel step response technique illustrates that the retraction of ionic charges from layer interfaces enables charge transport.
Akmaral Seitkhan, Marios Neophytou, Mindaugas Kirkus, Edy Abou-Hamad, Mohamed Nejib Hedhili, Emre Yengel, Yuliar Firdaus, Hendrik Faber, Yuanbao Lin, Leonidas Tsetseris, Iain McCulloch, and Thomas D. Anthopoulos
Advanced Functional Materials 1905810 (2019)
https://doi.org/10.1002/adfm.201905810
A simple approach that enables a consistent enhancement of the electron extracting properties of the widely used small-molecule Phen-NaDPO and its application in organic solar cells (OSCs) is reported. It is shown that addition of minute amounts of the inorganic molecule Sn(SCN)2 into Phen-NaDPO improves both the electron transport and its film-forming properties. Use of Phen-NaDPO:Sn(SCN)2 blend as the electron transport layer (ETL) in binary PM6:IT-4F OSCs leads to a remarkable increase in the cells’ power conversion efficiency (PCE) from 12.6% (Phen-NaDPO) to 13.5% (Phen-NaDPO:Sn(SCN)2). Combining the hybrid ETL with the best-in-class organic ternary PM6:Y6:PC70BM systems results to a similarly remarkable PCE increase from 14.2% (Phen-NaDPO) to 15.6% (Phen-NaDPO:Sn(SCN)2). The consistent PCE enhancement is attributed to reduced trap-assisted carrier recombination at the bulk-heterojunction/ETL interface due to the presence of new energy states formed upon chemical interaction of Phen-NaDPO with Sn(SCN)2. The versatility of this hybrid ETL is further demonstrated with its application in perovskite solar cells for which an increase in the PCE from 16.6% to 18.2% is also demonstrated.
Marios Neophytou, Michele De Bastiani, Nicola Gasparini, Erkan Aydin, Esma Ugur, Akmaral Seitkhan, Floriana Moruzzi, Yasmin Choaie, Alexandra J. Ramadan, Joel R. Troughton, Rawad Hallani, Achilleas Savva, Leonidas Tsetseris, Sahika Inal, Derya Baran, Frédéric Laquai, Thomas D. Anthopoulos, Henry J. Snaith, Stefaan De Wolf, and Iain McCulloch
ACS Appl. Energy Mater. (2019)
https://doi.org/10.1021/acsaem.9b01567
Charge transport layers strongly influence the performance of perovskite solar cells (PSCs). To date, compact layers and mesoporous scaffolds of titanium dioxide have emerged as good electron transport layers (ETL), enabling record power conversion efficiencies (PCE). However, these ETLs require sintering above 400 ¡ãC, which excludes them from low-temperature applications such as flexible devices and silicon-heterojunction tandems. Furthermore, instability of TiO2 under prolonged exposure to sunlight appears to be a critical issue. Here, we present the promising characteristics of low-temperature processed strontium titanate (STO) as an ETL to realize PSCs with 19% PCE. STO is a wide bandgap transparent inorganic perovskite. Compared with other low-temperature processed interlayers, STO reduces the parasitic absorption in the ultraviolet and visible range, improves the electron transport, and greatly increases the stability of the devices, retaining ¡«80% of their initial efficiency after 1000 h of constant white light illumination.
Moulay Ahmed Slimani
Masterthesis, Universite de Quebec, 2019
Based on current energy and environmental context, research in the photovoltaic field is growing very fast. Silicon photovoltaic (PV) cells dominate the world market. One of the reasons limiting the efficiency of silicon-based solar cells are the losses due to thermalization. multi-junction cells represent a solution to reduce these losses, but they are expensive too. The printing technique, therefore represents a viable alternative for it is a low temperature and a low-cost technique. Moreover, it can be realized on flexible devices and with unlimited raw material. The objectives of this thesis are thus to firstly realize perovskite solar cells using the Slot Die printing technique and then to optimize it to optimize a 4-terminal (4T) tandem silicon/perovskite cell. A simulation study by SETFOS (Semiconducting Emission Thin Film Optics Simulation) was made to understand and optimize the effect of thickness, mobility of charge carriers and bands energy on the efficiency of the perovskite solar cell. Then, a characterization of the absorption coefficient of other layers inside the cells were made using Lambda 750 UV / Vis / NIR and X-ray diffraction technique (XRD) were used to optimize the temperature and the annealing time of the perovskite film. The last part of this work was reserved to the study of the effects of the layers of the perovskite cell on the absorption of the mono-crystalline silicon cell. This experimental study allowed us to optimize the layers of the perovskite solar cell and to evaluate the feasibility of having a perovskite/silicon tandem solar cell.
Martin T. Neukom, Andreas Schiller, Simon Züfle, Evelyne Knapp, Jorge Ávila, Daniel Pérez-del-Rey, Chris Dreessen, Kassio P.S. Zanoni, Michele Sessolo, Henk J. Bolink, Beat Ruhstaller
ACS Applied Materials and Interfaces 11, 23320 (2019)
https://pubs.acs.org/doi/10.1021/acsami.9b04991
A variety of experiments on vacuum-deposited methylammonium lead iodide perovskite solar cells are presented, including JV curves with different scan rates, light intensity-dependent open-circuit voltage, impedance spectra, intensity-modulated photocurrent spectra, transient photocurrents, and transient voltage step responses. All these experimental data sets are successfully reproduced by a charge drift-diffusion simulation model incorporating mobile ions and charge traps using a single set of parameters. While previous modeling studies focused on a single experimental technique, we combine steady-state, transient, and frequency-domain simulations and measurements. Our study is an important step toward the quantitative simulation of perovskite solar cells, leading to a deeper understanding of the physical effects of these materials. The analysis of the transient current upon voltage turn-on in the dark reveals that the charge injection properties of the interfaces are triggered by the accumulation of mobile ionic defects. We show that the current rise of voltage step experiments allows for conclusions about the recombination at the interface. Whether one or two mobile ionic species are used in the model has only a minor influence on the observed effects. A delayed current rise observed upon reversing the bias from +3 to -3 V in the dark cannot be reproduced yet by our drift-diffusion model. We speculate that a reversible chemical reaction of mobile ions with the contact material may be the cause of this effect, thus requiring a future model extension. A parameter variation is performed in order to understand the performance-limiting factors of the device under investigation.
Toshinori Matsushima, Fatima Bencheikh, Takeshi Komino, Matthew R. Leyden, Atula S. D. Sandanayaka, Chuanjiang Qin and Chihaya Adachi
Nature 572, 502 (2019)
https://doi.org/10.1038/s41586-019-1435-5
We show that extraordinarily thick OLEDs can be fabricated by using the organic-inorganic perovskite methylammonium lead chloride, CH3NH3PbCl3 (MAPbCl3), instead of organics as the transport layers. Because MAPbCl3 films have high carrier mobilities and are transparent to visible light, we were able to increase the total thickness of MAPbCl3 transport layers to 2,000 nanometres—more than ten times the thickness of standard OLEDs—without requiring high voltage or reducing either internal electroluminescence quantum efficiency or operational durability. These findings will contribute towards a higher production yield of high-quality OLEDs, which may be used for other organic devices, such as lasers, solar cells, memory devices, and sensors.
T. Gahlmann, K. O. Brinkmann, T. Becker, C. Tückmantel, C. Kreusel, F. van gen Hassend, S. Weber, and T. Riedl
Adv. Energy Mater. 2020, 1903897
https://onlinelibrary.wiley.com/doi/full/10.1002/aenm.201903897
The authors show that impermeable electron transport layers (ETLs) enable the deposition of semitransparent AgNW electrodes from green aqueous dispersions on top of the perovskite cell without damage. Ultimately, semitransparent PSCs are demonstrated that provide an efficiency of 17.4%, which is the highest efficiency of semitransparent p-i-n perovskite solar cells with an AgNW top electrode.
U. Aeberhard, R. Häusermann, A. Schiller, B. Blülle and B. Ruhstaller
2020 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD), Turin, Italy, 2020, pp. 37-38
https://ieeexplore.ieee.org/document/9217773/
Description:
We present a comprehensive opto-electronic simulation framework for the computational analysis and optimization of perovskite-silicon tandem solar cells, consisting of a combination of a multiscale optical model for the simultaneous consideration of interference in thin coatings and scattering at textured interfaces with a mixed electronic-ionic drift-diffusion transport model that captures the peculiarities of the geometries and materials used in the tandem architecture.
X. Yang, Y. Lin, J. Liu, W. Liu, Q. Bi, X. Song, Jingxuan Kang,
F. Xu, L. Xu, M. N. Hedhili, D. Baran, X. Zhang, T. D. Anthopoulos, S. De Wolf
Adv. Mater. 2020, 2002608
https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.202002608
The authors developed an efficient electron‐selective contact for for crystalline silicon (c‐Si) and organic photovoltaic devices. Titanium oxynitride (TiOxNy), is deposited by Atomic‐layer‐deposition and demonstrated to be highly conductive with a proper work function (4.3 eV) and a wide bandgap (3.4 eV). A state‐of‐the‐art PCE of 22.3% is achieved for a c‐Si solar cell featuring a full‐area dopant‐free electron‐selective contact. Simultaneously, conductive TiOxNy is proven to be an efficient electron‐transport layer for organic photovoltaic (OPV) devices. A remarkably high PCE of 17.02% is achieved for an OPV device.
Qin, C., Matsushima, T., Potscavage, W.J. et al.
Nat. Photonics 14, 70–75 (2020).
https://doi.org/10.1038/s41566-019-0545-9
Description:
Perovskite light-emitting diodes are promising for next-generation lighting and displays because of their high colour purity and performance1. Although the management of singlet and triplet excitons is fundamental to the design of efficient organic light-emitting diodes, the nature of how excitons affect performance is still not clear in perovskite2,3,4 and quasi-two-dimensional (2D) perovskite-based devices5,6,7,8,9. Here, we show that triplet excitons are key to efficient emission in green quasi-2D perovskite devices and that quenching of triplets by the organic cation is a major loss path.
J. Lu, W. Feng, G. Mei, J. Sun, C. Yan, D. Zhang,
K. Lin, D. Wu, K. Wang, and Z. Wei
Adv. Sci. 2020, 2000689
https://onlinelibrary.wiley.com/doi/full/10.1002/advs.202000689
Description:
An ultrathin PEDOT:PSS hole transporter layer is prepared by a water stripping method. The PEDOT:PSS can enhance ηc and LEE simultaneously in Pero-LEDs thanks to the improved carrier mobility, more matched energy level alignment, and reduced photon loss. The EQEs of Pero-LEDs based on 3D, quasi-3D, and quasi-2D perovskites obtain enhancements of 42%, 87%, and 111%, and the corresponding maximum EQE reaches 17.6%, 15.0%, and 6.8%, respectively.
A.Seitkhan, M. Neophytou, R. K. Hallani, J.Troughton, N. Gasparini, H. Faber, E. Abou-Hamad, M.N. Hedhili, G. T. Harrison, D.Baran, L. Tsetseris, T. D. Anthopoulos and I. McCulloch
Adv. Funct. Mater. 2020, 2004273
https://onlinelibrary.wiley.com/doi/10.1002/adfm.202004273
Description:
A simple approach for improving the electron extraction of the PC60BM electron transport layer (ETL) is presented by sequentially depositing Al:ZnO (AZO) and triphenyl-phosphine oxide (TPPO) on top of it, in a p–i–n device configuration. The efficiency of the resulting CH3NH3PbI3-based solar cell is shown to improve from 14.6%, measured for the control PC60BM-only cell, to 17.9% for double-ETL (PC60BM/AZO) and 19.2% for triple-ETL (PC60BM/AZO/TPPO)-based devices, respectively.
J. Liu, W. Liu, E. Aydin, G. T. Harrison, F. H. Isikgor, X. Yang, A. S. Subbiah, S. De Wolf
ACS Appl. Mater. Interfaces 2020, 12, 21, 23874
https://pubs.acs.org/doi/10.1021/acsami.0c03660
Description:
The authors investigated spiro-OMeTAD, which is the most widely used HTL for n–i–p devices, and revealed improved power conversion efficiency (PCE) and stability in perovskite solar cells (PSCs). They also demonstrated the applicability of TPFB doping to other triphenylamine-based HTLs.
Xiao, X., Wang, K., Ye, T. et al.
Commun Mater 1, 81 (2020).
https://doi.org/10.1038/s43246-020-00084-0
A new strategy has been introduced to enhance hole injection in perovskite light-emitting diodes (LEDs) by introducing an electric dipole layer. The use of MoO3 as the electric dipole layer between PEDOT:PSS (hole injection layer) and PVK (hole transport layer) generates electric dipoles, which efficiently enhance hole injection and increase the recombination rate.
Theoretical analysis and capacitance-voltage analyses demonstrate efficient hole injection by introducing the electric dipole layer. The proposed electric dipole layer structure has led to a high current efficiency of 72.7 cd A−1, showing that electric dipole layers can significantly enhance the performance of perovskite LEDs.
Simulations
The electrical simulations were performed with Setfos, which solves the drift-diffusion equations for electron and holes, and considers exciton formation, mdiffusion, and decay in the framework of radiating dipoles inside amcavity including the Purcell effect.
Mohammad Alvar, Paul W. M. Blom & Gert-Jan A. H. Wetzelaer
ACS Appl. Mater. Interfaces 2020, 12, 21, 23874
https://www.nature.com/articles/s41467-020-17868-0
Description:
Researchers at the Max Planck Institute for Polymer Research developed a rigorous framework to extract the charge mobility from the SCLC-JV characteristics of pero-PVs. This work demonstrates also how to combine experiments and simulations to gain reliable insights into the transport mechanisms in a perovskite. PAIOS helped them performing scan-dependent electrical characterizations on their devices at different temperatures.
Our tutorial “Characterization Techniques for Perovskite and Organic Solar Cells” can help also understanding all the optoelectrical characterizations that can be performed on a solar cell.
