Article
Materials Science, Multidisciplinary
Daniel Abou-Ras, Aleksandra Nikolaeva, Maximilian Krause, Lars Korte, Helena Stange, Roland Mainz, Ekin Simsek Sanli, Peter A. van Aken, Takeyoshi Sugaya, Jiro Nishinaga
Summary: Evidence shows that dislocations in CIGS thin films do not affect the optoelectronic properties, unlike grain boundaries. The unique behavior may be attributed to the extensive elemental redistribution around dislocation cores, leading to a shift of defect states towards the band edges.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2021)
Article
Crystallography
Kanwen Hou, Guohao Liu, Jia Yang, Wei Wang, Lixin Xia, Jun Zhang, Baoqiang Xu, Bin Yang
Summary: This article investigates the preparation of Cu(In, Ga)Se-2 (CIGS) thin films using vacuum electrodeposition, and elucidates the mechanism involved. The incorporation of gallium into the films can be controlled by inhibiting pH changes at the cathode region in a vacuum environment. The formation of Ga2O3 was suppressed at 3 kPa through the introduction of a low-conductivity secondary phase, as confirmed by Raman and X-ray photoelectron spectroscopy. The preparation process employed higher current density, lower diffusion impedance, and charge transfer impedance, resulting in larger particle sizes in the films.
Article
Physics, Applied
Aaron S. Gehrke, David E. Sommer, Scott T. Dunham
Summary: In order to improve the performance of Cu(In,Ga)Se-2 thin-film photovoltaic devices, this study investigates the diffusion pathways of In and Ga. Density functional theory is used to identify the most probable defect complexes and mechanisms, as well as calculate their binding energies and migration barriers. Analytic models and simulations are employed to predict the diffusivity of In and Ga under various conditions.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Mohit Raghuwanshi, Manjusha Chugh, Giovanna Sozzi, Ana Kanevce, Thomas D. Kuehne, Hossein Mirhosseini, Roland Wuerz, Oana Cojocaru-Miredin
Summary: This study investigates both Cu-poor and Cu-rich CIGS solar cells and shows the superior properties of the internal interfaces of Cu-poor cells, such as p-n junction and grain boundaries, which make them the highest-efficiency devices. By employing a correlative microscopy approach, key factors governing the device performance are discovered.
ADVANCED MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Hanna Bishara, Lena Langenohl, Xuyang Zhou, Baptiste Gault, James P. Best, Gerhard Dehm
Summary: The study focuses on the effect of Fe-alloying on the resistivities of grains and grain boundaries in Cu thin films. Cu films with varying grain sizes and Fe compositions were prepared. The properties, morphology, and compositions of bulk and grain boundaries were analyzed using different methods. Both local electrical measurements and global resistivity characterization were performed to obtain specific resistivities and calculate the grain boundary reflection coefficient. It was found that alloying significantly increased the resistivity of grain boundaries while causing only minor influence on the grain interior.
SCRIPTA MATERIALIA
(2023)
Article
Energy & Fuels
Mohit Raghuwanshi, Jens Keutgen, Antonio Massimiliano Mio, Hossein Mirhosseini, Thomas D. Kuehne, Oana Cojocaru-Miredin
Summary: The grain boundaries (GBs) in CIGS solar cells are important for their efficiency, especially in cells with polycrystalline absorbers. Previous studies have shown that the traits of GBs in CIGS are directly related to their composition. However, this relationship cannot be determined for twin boundaries (TBs). In this study, high-resolution scanning transmission electron microscopy is used to investigate TBs and their differences, and it is found that electrically neutral TBs are cation-anion terminated, while electrically beneficial TBs are cation-cation terminated. The presence of Cu vacancies near cation-cation TBs leads to a passivated TB and better electron transport.
Article
Materials Science, Multidisciplinary
Benjamin Belfore, Deewakar Poudel, Shankar Karki, Sina Soltanmohammad, Elizabeth Palmiotti, Thomas Lepetit, Angus Rockett, Sylvain Marsillac
Summary: In this study, it was demonstrated that InCl3 can effectively be used for recrystallization of CIGS at temperatures as low as 450 degrees C, but it also induces a modification of the surface composition.
Article
Energy & Fuels
Ryotaro Fukuda, Takahito Nishimura, Akira Yamada
Summary: The behavior of carriers for an electron-beam-induced current (EBIC) evaluation in polycrystalline Cu(In, Ga)Se-2 (CIGS) thin-film solar cells was experimentally and theoretically analyzed. The analysis revealed four features in the EBIC signal profiles of the CIGS layers: peaks at grain boundaries (GBs), narrowed peaks near the surface, shifted peaks near the surface, and double peaks at the GBs and surface. These findings will contribute to a comprehensive understanding of the carrier transport mechanism in polycrystalline CIGS, which is crucial for achieving high-efficiency CIGS solar cells.
PROGRESS IN PHOTOVOLTAICS
(2023)
Review
Chemistry, Multidisciplinary
Oana Cojocaru-Miredin, Mohit Raghuwanshi, Roland Wuerz, Sascha Sadewasser
Summary: Cu(In,Ga)Se-2 thin-film solar cells have garnered research interest for their cost efficiency and high cell performance, but the presence of grain boundaries can lead to increased recombination activity, affecting cell efficiency.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Physics, Applied
E. M. Spaans, J. de Wild, T. J. Savenije, B. Vermang
Summary: Room temperature photoluminescence (PL) measurements were modeled using the unified potential fluctuation (UPF) model to quantify potential fluctuations in Cu (In, Ga) Se2 (CIGS) absorber layers, showing a clear improvement compared to previous models. Additionally, an interference function was used to correct possible interference distortions in some PL measurements.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Physical
Deewakar Poudel, Benjamin Belfore, Tasnuva Ashrafee, Shankar Karki, Grace Rajan, Angus Rockett, Sylvain Marsillac
Summary: Post-deposition treatments with indium bromide vapor at 400 and 500 degrees Celsius lead to larger grains and higher conductivity in Cu(In,Ga)Se-2 thin films compared to simple annealing under selenium. These properties are attributed to a modification of elemental profiles, particularly for gallium and sodium.
Article
Crystallography
Chul Kang, Gyuseok Lee, Woo-Jung Lee, Dae-Hyung Cho, Inhee Maeng, Yong-Duck Chung, Chul-Sik Kee
Summary: Ar-ion implantation increases the THz emission and carrier dynamics of CIGS films.
Article
Energy & Fuels
Elizabeth Palmiotti, Sylvain Marsillac, Angus Rockett
Summary: This study compares and evaluates the metal halide treatments of CdTe films and CIGS, finding that CdTe films have lower manufacturing costs, while CIGS requires higher temperatures and lower rates to achieve high efficiency. Silver halides are beneficial for the transport of all species, while compounds containing gallium and indium may pose some issues. Copper compounds have low vapor pressure but exhibit high mobility in CIGS.
PROGRESS IN PHOTOVOLTAICS
(2023)
Article
Energy & Fuels
Jan Keller, Patrick Pearson, Nina Shariati Nilsson, Olof Stolt, Lars Stolt, Marika Edoff
Summary: The study focused on the impact of absorber stoichiometry in ACIGS solar cells with bandgaps greater than 1.40 eV, showing that moving away from AgGaSe2 composition can reduce ordered vacancy compounds, leading to improved device performance. An inverse correlation between V-OC and J(SC) was observed, with capacitance profiling revealing enhanced carrier collection in fully depleted samples. Additionally, the measurement of a solar cell with V-OC = 0.916 V at E-g = 1.46 eV represents the highest reported value for this bandgap to date.
Article
Energy & Fuels
Pedro Anacleto, Carl Hagglund, Wei-Chao Chen, Milan Kovacic, Janez Krc, Marika Edoff, Sascha Sadewasser
Summary: Research reveals that the use of nanostructured hafnium oxide rear passivation layers can improve the performance of ultra-thin Cu(In,Ga)Se-2 solar cells. Experimental results show that solar cells with a 500 nm thick CIGS absorber layer and a 40 nm thick HfO2 passivation layer exhibit enhanced performance in terms of V-oc and J(sc), resulting in an average efficiency increase of 1.2%. Simulation work confirms that the optical properties of ultra-thin CIGS solar cells are minimally affected by the HfO2 passivation layer.
PROGRESS IN PHOTOVOLTAICS
(2022)
Article
Chemistry, Physical
Kamala Khanal Subedi, Adam B. Phillips, Niraj Shrestha, Fadhil K. Alfadhili, Anna Osella, Indra Subedi, Rasha A. Awni, Ebin Bastola, Zhaoning Song, Deng-Bing Li, Robert W. Collins, Yanfa Yan, Nikolas J. Podraza, Michael J. Heben, Randy J. Ellingson
Summary: Bifacial solar cells have the potential to increase energy yield and reduce costs, but thin film bifacial solar cells lag behind crystalline silicon cells. Introducing CuxAlOy as a back buffer layer can improve efficiency.
Review
Nanoscience & Nanotechnology
Julie Euvrard, Yanfa Yan, David B. Mitzi
Summary: Halide perovskites have excellent semiconductor properties and are crucial for various devices, yet achieving reliable electrical doping remains challenging. This Review discusses semiconductor doping fundamentals, different doping strategies, characterization techniques, and emphasizes the challenges that need to be overcome for controlling the electronic properties of this important material class.
NATURE REVIEWS MATERIALS
(2021)
Article
Multidisciplinary Sciences
Ji Hao, Young-Hoon Kim, Severin N. Habisreutinger, Steven P. Harvey, Elisa M. Miller, Sean M. Foradori, Michael S. Arnold, Zhaoning Song, Yanfa Yan, Joseph M. Luther, Jeffrey L. Blackburn
Summary: The study demonstrates a new method for optical memory and brain-inspired neuromorphic information processing, utilizing versatile heterojunctions between metal-halide perovskite nanocrystals and semiconducting single-walled carbon nanotubes to achieve long-lived, writable, and erasable persistent photoconductivity. This approach enables optical switching and basic neuromorphic functions at low energy consumption levels.
Article
Energy & Fuels
Deng-Bing Li, Canglang Yao, S. N. Vijayaraghavan, Rasha A. Awni, Kamala K. Subedi, Randy J. Ellingson, Lin Li, Yanfa Yan, Feng Yan
Summary: CdTe solar cells doped with group V elements using an ex situ approach show improved open-circuit voltages and device stability, overcoming limitations associated with copper doping. Li et al. have proposed a method based on group V chloride solutions and low-temperature annealing for effective doping.
Article
Chemistry, Physical
Ramez Hosseinian Ahangharnejhad, Zhaoning Song, Tamanna Mariam, Jayla J. Gardner, Geethika K. Liyanage, Zahrah S. Almutawah, Bhuiyan M. M. Anwar, Maxwell Junda, Nikolas J. Podraza, Adam B. Phillips, Yanfa Yan, Michael J. Heben
Summary: Using a sputtered SiO2 barrier coating can effectively protect metal halide perovskite solar cells from degradation in high-humidity environments, extending their lifetimes. LBIC data indicate that this approach performs well in preventing degradation initiation at the edges of scribed lines, which is beneficial for the fabrication of monolithically integrated modules.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Allen Zhao, Zhaoning Song, Rasha Awni, Yanfa Yan
Summary: Research on inorganic-organic metal halide perovskites has shown potential for various applications, but is limited by conductivity contributions and soft lattice structures. The presence and impact of ferroelectricity in MAPbI(3) is still debated. Utilizing a Sawyer-Tower measurement circuit, this study found no ferroelectric hysteresis in the perovskite capacitor, with a critical change in P-E loops at around 160K attributed to a crystal phase transition. These findings offer insights into the material and device properties of halide perovskites.
Article
Nanoscience & Nanotechnology
Biwas Subedi, Chongwen Li, Cong Chen, Dachang Liu, Maxwell M. Junda, Zhaoning Song, Yanfa Yan, Nikolas J. Podraza
Summary: The Urbach energy is a commonly used indicator of the electronic quality of thin-film materials in solar cells, and is influenced by the anion-cation composition. The correlation between the Urbach energy and the open-circuit voltage deficit of the perovskite thin film shows a direct relationship. However, some perovskite films show a lower Urbach energy but a higher open-circuit voltage deficit due to issues related to material quality and film processing techniques.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Suman Rijal, Deng-Bing Li, Rasha A. Awni, Chuanxiao Xiao, Sandip S. Bista, Manoj K. Jamarkattel, Michael J. Heben, Chun-Sheng Jiang, Mowafak Al-Jassim, Zhaoning Song, Yanfa Yan
Summary: A method to optimize the performance of Sb2Se3 thin-film solar cells by introducing a seed layer and post-treatment is introduced, resulting in the successful fabrication of Sb2Se3 planar heterojunction solar cells with high conversion efficiency.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Zhaoning Song, Chongwen Li, Lei Chen, Yanfa Yan
Summary: Bifacial perovskite solar cells offer the potential for higher power output and enhanced durability compared to traditional devices, thanks to the unique optoelectronic properties of perovskite material and the use of transparent conducting oxide electrodes to prevent electrode corrosion. Despite the limitations and challenges, bifacial perovskite solar cells are increasingly seen as a viable commercialization pathway for mainstream solar power generation and building-integrated PV systems. Advantages include high power output, improved device durability, and lower economic and environmental costs.
ADVANCED MATERIALS
(2022)
Article
Multidisciplinary Sciences
Fei Zhang, So Yeon Park, Canglang Yao, Haipeng Lu, Sean P. Dunfield, Chuanxiao Xiao, Sona Ulicna, Xiaoming Zhao, Linze Du Hill, Xihan Chen, Xiaoming Wang, Laura E. Mundt, Kevin H. Stone, Laura T. Schelhas, Glenn Teeter, Sean Parkin, Erin L. Ratcliff, Yueh-Lin Loo, Joseph J. Berry, Matthew C. Beard, Yanfa Yan, Bryon W. Larson, Kai Zhu
Summary: The performance of 3D perovskite solar cells can be improved by treating the surface with 2D layered perovskites that have efficient charge transport. Adjusting the arrangement of organic molecules enhances hole transport and power conversion efficiency. The use of a stable 2D surface layer also improves the performance and stability of 3D perovskite solar cells.
Article
Chemistry, Physical
Daming Zheng, Tao Zhu, Yanfa Yan, Thierry Pauporte
Summary: Utilizing multiple cations of the 1A alkali metal column to prepare perovskite films can improve photovoltaic properties, with NH4Cl additives enhancing solubility and promoting perovskite phase formation. The addition of NH4Cl also leads to more homogeneous distribution of alkali metals, improving overall crystallization quality and achieving high power conversion efficiency.
ADVANCED ENERGY MATERIALS
(2022)
Article
Energy & Fuels
Manoj K. Jamarkattel, Adam B. Phillips, Kamala Khanal Subedi, Ebin Bastola, Jacob M. Gibbs, Jared D. Friedl, Suman Rijal, Dipendra Pokhrel, Rasha A. Awni, Deng-Bing Li, John Farrell, Robert F. Klie, Xavier Mathew, Yanfa Yan, Randy J. Ellingson, Michael J. Heben
Summary: The study demonstrates enhanced performance in CdTe devices by incorporating solution-processed CuxAlOy to form a back-buffer layer, resulting in increased efficiency and improved current characteristics. Reduction in carrier recombination can lead to improved performance in photovoltaic devices.
IEEE JOURNAL OF PHOTOVOLTAICS
(2022)
Article
Energy & Fuels
Ebin Bastola, Adam B. Phillips, Griffin Barros-King, Manoj K. Jamarkattel, Deng-Bing Li, Abdul Quader, Dipendra Pokhrel, Jared Friedl, Jacob M. Gibbs, Xavier Mathew, Yanfa Yan, Randy J. Ellingson, Michael J. Heben
Summary: CdSe thickness and Cu doping are crucial for achieving high efficiency in CdTe solar cells. CdSe thickness plays a significant role in device performance, with a critical thickness determined at 120 nm. Increasing the Cu doping process temperature can lead to an increase in CdSe thickness and overall device efficiency improvement.
IEEE JOURNAL OF PHOTOVOLTAICS
(2022)
Article
Energy & Fuels
Zhenyi Ni, Haoyang Jiao, Chengbin Fei, Hangyu Gu, Shuang Xu, Zhenhua Yu, Guang Yang, Yehao Deng, Qi Jiang, Ye Liu, Yanfa Yan, Jinsong Huang
Summary: The study reveals the location, mechanisms, and defects involved in the performance degradation of p-i-n perovskite solar cells under illumination or reverse bias. The efficiency decreases over time, yet the introduction of a hole-blocking layer between the layers can improve the reverse-bias stability. Charged iodide interstitial defects within the device layers are observed and found to contribute to efficiency degradation under both light and reverse bias conditions.
Article
Nanoscience & Nanotechnology
Biwas Subedi, Chongwen Li, Cong Chen, Dachang Liu, Maxwell M. Junda, Zhaoning Song, Yanfa Yan, Nikolas J. Podraza
Summary: The Urbach energy, indicating the electronic quality of thin-film materials used in solar cells, is influenced significantly by the anion-cation composition in hybrid inorganic-organic metal halide perovskites. Different compositions lead to variations in the Urbach energy, demonstrating a direct relationship with the open-circuit voltage deficit in solar cells utilizing these materials.
ACS APPLIED MATERIALS & INTERFACES
(2022)
