Article
Energy & Fuels
Rupendra Kumar Sharma, Mathieu Boccard, Jakub Holovsky
Summary: Heterojunction carrier selective contacts play a crucial role in the efficiency and performance of solar cells. By studying the requirements for these contacts under different illumination levels, a new metric called contact strength has been defined to describe their ability. Key parameters such as doping, contact layer thickness, and electrode work-function have been identified as important factors in determining contact strength.
Article
Energy & Fuels
Rachel Woods-Robinson, Angela N. Fioretti, Jan Haschke, Mathieu Boccard, Kristin A. Persson, Christophe Ballif
Summary: In this study, simulation of the (n)c-Si/(i)a-Si:H/p-layer interface explored the influence of six material parameters on SHJ performance. The findings show significant impact on fill factor (FF) from thickness, doping, and E-VB, with optimal E-VB aligning about 0.1 eV higher than a-Si:H's valence band edge energy. Sensitivity analyses highlight the importance of optimizing both E-VB and doping simultaneously for improved performance.
IEEE JOURNAL OF PHOTOVOLTAICS
(2021)
Article
Chemistry, Multidisciplinary
Yaohui Li, Xiang Wu, Guangzheng Zuo, Yufei Wang, Xianjie Liu, Yanxian Ma, Bolun Li, Xu-Hui Zhu, Hongbin Wu, Jian Qing, Lintao Hou, Wanzhu Cai
Summary: Selective electron transport and extraction are crucial for photovoltaic devices. This study presents an electron transport layer (ETL) configuration composed of a solution-processed n-n organic heterojunction to enhance electron transport and boost power conversion efficiency (PCE) in organic photovoltaics (OPV). The n-n heterojunction consists of a narrow-band n-type conjugated polymer layer (PNDIT-F3N) and a wide-band n-type conjugated molecule layer (Phen-NaDPO). The performance improvement in OPVs with different active layers is attributed to selective carrier transport properties, reduced recombination, and good film-forming quality of the ETL configuration.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Xinbo Yang, Jingxuan Kang, Wenzhu Liu, Xiaohong Zhang, Stefaan De Wolf
Summary: A simple and efficient solution-doping process was proposed for preparing high-quality poly-Si-based passivating contacts, achieving low contact recombination parameter and resistivity through optimized doping and thermal annealing. The method proved to be a promising alternative to gas/ion implantation doping for manufacturing poly-Si passivating contacts in solar cells, leading to the best power conversion efficiency on a planar substrate.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Yuan Xie, Enxiu Wu, Shuangqing Fan, Guangyu Geng, Xiaodong Hu, Linyan Xu, Sen Wu, Jing Liu, Daihua Zhang
Summary: A highly effective N2O plasma process was developed to treat MoTe2/MoS2 heterojunctions, allowing independent adjustment of hole and electron concentrations and creation of opposite doping on the two sides of the junction in a single step. This new approach provides a versatile method for constructing multifunctional electronic devices.
Article
Nanoscience & Nanotechnology
Sung-In Mo, Sungjin Choi, Jeong-Ho An, Bo-Jong Kim, Kwan Hong Min, Sungeun Park, Ji-Eun Hong, Soong Ju Oh, Hee-eun Song, Joon-Ho Oh, Ka-Hyun Kim
Summary: This study investigates the microstructural evolution, dopant in-diffusion, and carrier transport mechanism in the electron and hole contacts of poly-Si/SiOx solar cells. The results demonstrate that the passivation properties and carrier transport mechanisms are strongly influenced by the microstructural evolution and dopant in-diffusion. Electron and hole contacts exhibit common behaviors regarding microstructural evolution and dopant in-diffusion, but hole contacts show relatively inferior electrical properties overall.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Nanoscience & Nanotechnology
Jiali Wang, Sieu Pheng Phang, Christian Samundsett, Zhuofeng Li, Thien N. Truong, Jie Yang, Zhao Wang, Peiting Zheng, Xinyu Zhang, Hieu T. Nguyen, Daniel Macdonald, Josua Stuckelberger
Summary: In this study, high-quality localized phosphorus-doped polycrystalline silicon passivating contacts with nanoscale poly-Si film on an ultrathin SiOx layer were fabricated using an inkjet printing technique. The effects of printer settings, dopant concentration, and annealing temperature on the contact performance were investigated. Good surface passivation was achieved with optimized conditions, and after hydrogenation treatment, the implied open-circuit voltage was further improved.
ACS APPLIED NANO MATERIALS
(2023)
Article
Physics, Applied
Jonathan L. Bryan, Joe V. Carpenter, Zhengshan J. Yu, Ashling (Mehdi) Leilaeioun, Jianwei Shi, William Weigand, Kathryn C. Fisher, Zachary C. Holman
Summary: Contacts implemented on the rear side of silicon heterojunction solar cells, such as a-Si:H(i)/a-Si:H(n)/Al and a-Si:H(i)/a-Si:H(p)/Al, demonstrate promising performance in electrical test structures and full-area solar cells. The stability and performance of the contacts are affected by annealing temperature and thickness of doped a-Si:H layers. Transmission electron microscopy and energy-dispersive x-ray spectroscopy analysis help to explain Al-Si interactions at the interfaces and understand the limiting materials properties affecting contact stability.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Energy & Fuels
Julie Dreon, Jean Cattin, Gabriel Christmann, Davi Febba, Vincent Paratte, Luca Antognini, Wenjie Lin, Sylvain Nicolay, Christophe Ballif, Mathieu Boccard
Summary: The study found that the optimal efficiency is achieved with a MoOx layer thickness of 4 nm, outperforming thicker layers. However, MoOx films thinner than 4 nm lead to a loss of passivation and selectivity.
IEEE JOURNAL OF PHOTOVOLTAICS
(2021)
Article
Energy & Fuels
Lingze Yao, Zhiqin Ying, Wei Wang, Zhenhai Yang, Juanjuan Sun, Xinlong Wang, Xi Yang, Yuheng Zeng, Baojie Yan, Xiaoliang Xu, Jichun Ye
Summary: The use of a ZrAcac layer as an electron-selective contact has been proven to effectively improve the efficiency and stability of silicon solar cells by reducing contact resistivity and interface work function, resulting in dipole formation to enhance charge transfer.
Article
Energy & Fuels
Xiaoning Liu, Qian Huang, Xiufang Yang, Jiakai Zhou, Chengchao Ren, Xianglin Su, Zhiyuan Xu, Ying Zhao, Guofu Hou
Summary: This study investigated the potential of using metal oxides to construct DASH solar cells through simulation analysis. It was found that the use of ZnO and MoOX as carrier-selective layers can significantly improve the performance of the cells, with a maximum simulated conversion efficiency of 27.64%.
Article
Chemistry, Multidisciplinary
Onejae Sul, Hojun Seo, Eunsuk Choi, Sunjin Kim, Jinsil Gong, Jiyoung Bang, Hyoungbeen Ju, Sehoon Oh, Yeonsu Lee, Hyeonjeong Sun, Minjin Kwon, Kyungnam Kang, Jinki Hong, Eui-Hyeok Yang, Yunchul Chung, Seung-Beck Lee
Summary: Development of a reliable doping method for 2D materials is crucial for their adoption in future microelectronic circuits. This study demonstrates hole doping of tungsten disulfide using a silicon substrate as the dopant medium. The fabricated devices show ultra-low power consumption, high stability, and a large output current ratio.
Article
Energy & Fuels
Guangtao Yang, Bas van de Loo, Maciej Stodolny, Gianluca Limodio, Jimmy Melskens, Bart Macco, Paula Bronsveld, Olindo Isabella, Arthur Weeber, Miro Zeman, W. M. M. Kessels
Summary: This study investigates the application of Al_2O_3 prepared by atomic layer deposition as a hydrogenating capping layer for polycrystalline silicon passivating contacts. Results show that Al_2O_3/SiN_x stack greatly enhances passivation quality for various types of poly-Si layers, providing guidelines for significantly improving their passivation performance.
IEEE JOURNAL OF PHOTOVOLTAICS
(2022)
Article
Energy & Fuels
Luca Serenelli, Luca Martini, Francesca Menchini, Massimo Izzi, Giampiero Cesare, Giuseppe Condorelli, Cosimo Gerardi, Delfina Munoz, Mario Tucci
Summary: Crystalline silicon-based heterojunction solar cells have become the preferred choice for manufacturing companies due to their low temperature processes and high efficiencies. However, the maximum efficiency is still limited by factors such as Fill Factor and base contact issues. Addressing hidden barriers at the base contact and recognizing barriers at the emitter side are crucial for improving cell efficiency.
PROGRESS IN PHOTOVOLTAICS
(2021)
Article
Materials Science, Multidisciplinary
Bisma Bilal, Hakim Najeeb-ud-Din
Summary: A hybrid carrier selective contact scheme based on a blend of industrially adaptable tunnel oxide passivated rear and a low-cost material based front is investigated. The proposed cell performs superior or equivalent to the existing designs with additional economic and manufacturing benefits.
Article
Energy & Fuels
Mathieu Boccard, Luca Antognini, Vincent Paratte, Jan Haschke, Minh Truong, Jean Cattin, Julie Dreon, Wenjie Lin, Laurie-Lou Senaud, Bertrand Paviet-Salomon, Sylvain Nicolay, Matthieu Despeisse, Christophe Ballif
Summary: This study discusses several modifications to improve the optoelectronic performance of window-layer stack in both-side-contacted silicon heterojunction solar cells, including replacing the P-type layer, front transparent electrode, capping with silicon-oxide film, and applying postfabrication electrical biasing treatment. Combining all these modifications enables the fabrication of a highly transparent and electrically well-performing window-layer stack, leading to a screen-printed silicon heterojunction solar cell with 24.1% efficiency. Paths towards industrialization and further improvements are also discussed.
IEEE JOURNAL OF PHOTOVOLTAICS
(2021)
Article
Materials Science, Multidisciplinary
Jakub Holovsky, Eva Horynova, Lukas Horak, Katarina Ridzonova, Zdenek Remes, Lucie Landova, Rupendra Kumar Sharma
Summary: Molybdenum oxide is a material with high bandgap, work function, and other interesting properties. Using Pulsed Laser Deposition, researchers were able to deposit high transparency MoO3 layers from stoichiometric MoO3 and metal Mo targets at different temperatures and oxygen pressures. Optical properties were accurately tracked using Photothermal Deflection Spectroscopy and Spectral Ellipsometry, while crystallinity and surface morphology were monitored using X-ray diffraction and Scanning Electron Microscopy. Increasing temperature led to smoother, denser layers, narrowing bandgap, and increased sub-gap absorption, with crystallization occurring above 400 degrees C. Sub-gap absorption around 1000 nm depended on temperature and weakly on oxygen pressure.
Article
Physics, Applied
Jia Ding, Calli M. Campbell, Jacob J. Becker, Cheng-Ying Tsai, Stephen T. Schaefer, Tyler T. McCarthy, Mathieu Boccard, Zachary C. Holman, Yong-Hang Zhang
Summary: Monocrystalline 1.7 eV Mg0.13Cd0.87Te/MgxCd1-xTe double heterostructure (DH) solar cells were grown by molecular beam epitaxy, showing improved performance with varying Mg compositions in the barrier layers. Temperature-dependent V-OC measurements revealed that most carrier recombination occurred outside the DHs. Simulation results indicated contributions to J(SC) loss from the p-type a-Si:H layer and the Mg0.37Cd0.63Te top barrier in the device with the highest efficiency.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Energy & Fuels
Jean Cattin, Delphine Petri, Jonas Geissbuehler, Matthieu Despeisse, Christophe Ballif, Mathieu Boccard
Summary: The effect of light soaking and forward electric bias treatment on silicon heterojunction solar cells and modules, along with the influence of thermal treatment during lamination, is investigated. It is found that the lamination process can partially reset the improved performance after electric bias or light soaking. However, a second treatment after lamination can improve performance again, leading to similar final performance regardless of the prelamination treatment.
IEEE JOURNAL OF PHOTOVOLTAICS
(2022)
Article
Chemistry, Physical
Amalraj Peter Amalathas, Lucie Landova, Katarina Ridzonova, Lukas Horak, Pavla Bauerova, Jakub Holovsky
Summary: The study demonstrates an effective method for improving mesoporous TiO2/perovskite interfacial characteristics by modifying mesoporous TiO2 with potassium treatment, leading to enhanced perovskite crystallization, reduced trap sites in TiO2, and improved charge collection efficiency across the interface, resulting in a high power conversion efficiency of 20.60% for the PSC based on K-treated mesoporous TiO2.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Jakub Holovsky, Jakub Sebera, Vladimir Sychrovsky, Jan Zemen, Stefaan De Wolf, Christophe Ballif
Summary: In this work, periodic DFT simulations were used to assign vibrational spectra on nanorough wet-processed hydrogenated Si(111) surfaces, providing a better understanding of the imperfect and nanorough Si(111) surfaces through vibrational spectroscopy.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Review
Nanoscience & Nanotechnology
Christophe Ballif, Franz-Josef Haug, Mathieu Boccard, Pierre J. Verlinden, Giso Hahn
Summary: This paper reviews the recent evolution of crystalline silicon solar cells, analyzes the current status of research and industrial development, and looks into the future prospects. The improvements in materials and processing have greatly reduced the cost and increased the efficiency of crystalline silicon photovoltaics, making it an important low-cost source of electricity. The paper also discusses the challenges and requirements for other photovoltaic technologies to compete with silicon on the mass market.
NATURE REVIEWS MATERIALS
(2022)
Article
Chemistry, Physical
Esma Ugur, Martin Ledinsky, Thomas G. Allen, Jakub Holovsky, Ales Vlk, Stefaan De Wolf
Summary: The Urbach energy is a metric used to describe the disorder in a semiconductor and can be measured directly using optical techniques. It provides a single value that represents the optoelectronic performance potential of a semiconductor. In solar cells, the Urbach energy has been found to predict the minimal open-circuit-voltage deficit of a material. Considering the Urbach energy in performance calculations gives more realistic limits for power conversion efficiency than classical theories. It is also often correlated with the Stokes shift and carrier mobility of a semiconductor.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Energy & Fuels
Laurie-Lou Senaud, Gabriel Christmann, Luca Antognini, Antoine Descoeudres, Jonas Geissbuhler, Mathieu Boccard, Sylvain Nicolay, Matthieu Despeisse, Christophe Ballif, Bertrand Paviet-Salomon
Summary: This study investigates and characterizes the electrical losses affecting the collection of photogenerated carriers in silicon heterojunction (SHJ) solar cells. It explores the material properties controlling the physical coupling between the n-type hydrogenated silicon and the transparent conductive oxide (TCO) layers, and develops different material layers to study the device performance. The study also optimizes the multilayers to achieve low series resistance and high passivation.
IEEE JOURNAL OF PHOTOVOLTAICS
(2022)
Article
Energy & Fuels
Rupendra Kumar Sharma, Mathieu Boccard, Jakub Holovsky
Summary: Heterojunction carrier selective contacts play a crucial role in the efficiency and performance of solar cells. By studying the requirements for these contacts under different illumination levels, a new metric called contact strength has been defined to describe their ability. Key parameters such as doping, contact layer thickness, and electrode work-function have been identified as important factors in determining contact strength.
Article
Energy & Fuels
Laurie-Lou Senaud, Luca Antognini, Gabriel Christmann, Mathieu Boccard, Matthieu Despeisse, Christophe Ballif, Bertrand Paviet-Salomon
Summary: This article applies the transfer length method (TLM) measurements under variable illumination to study p-type carrier selective passivating contacts (CSPCs) in silicon heterojunction (SHJ) technology. The study finds that illumination has a strong impact on the contact resistivity (rho(c)) of p-type CSPCs, similar to what was previously observed in n-type CSPCs. Furthermore, the study demonstrates the different effects of illumination on rho(c) depending on the doping of the p-type hydrogenated silicon layer. The results provide insights for understanding TLM measurements under illumination and investigating carrier transport and electrical losses in CSPC solar cells.
IEEE JOURNAL OF PHOTOVOLTAICS
(2023)
Article
Energy & Fuels
Mathieu Boccard, Luca Antognini, Jean Cattin, Julie Dreon, Wenjie Lin, Vincent Paratte, Deniz Turkay, Christophe Ballif
Summary: Silicon heterojunction (SHJ) solar cells have achieved power conversion efficiencies above 25% with various device architectures and industrial size wafers. However, to accurately assess efficiency potential and further develop the technology, the identification and detailed analysis of high-performing device configurations are crucial. This study presents lab-scale front-junction cells with certified efficiency of 24.44% and improvements in front-side silicon layers and rear reflector. Power loss analysis reveals that parasitic absorption in the front layer-stack remains a major source of loss. Approaches like localization of highly absorbing front layers and switching to a rear-junction architecture are suggested to circumvent this loss.
IEEE JOURNAL OF PHOTOVOLTAICS
(2023)
Article
Chemistry, Physical
Katarina Ridzonova, Roman Grill, Amalraj Peter Amalathas, Branislav Dzurnak, Neda Neykova, Lukas Horak, Peter Fiala, Xin Yu Chin, Christian M. Wolff, Quentin Jeangros, Jakub Holovsky
Summary: This study investigates the effect of light soaking on mixed-halide perovskite materials and devices using Fourier-Transform photocurrent spectroscopy, photoluminescence, and current density-voltage (J-V) measurements. The results show the formation of phase segregation and deep defects under light soaking, as well as the influence of grain size on the degree of segregation.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Meeting Abstract
Chemistry, Multidisciplinary
Lukas Horak, Amalraj Peter Amalathas, Jakub Holovsky
ACTA CRYSTALLOGRAPHICA A-FOUNDATION AND ADVANCES
(2021)