Article
Nanoscience & Nanotechnology
Naoki Higashitarumizu, Shiekh Zia Uddin, Daniel Weinberg, Nima Sefidmooye Azar, I. K. M. Reaz Rahman, Vivian Wang, Kenneth B. B. Crozier, Eran Rabani, Ali Javey
Summary: The photophysics of black phosphorus, an optoelectronic material, was investigated. It was found that the photoluminescence quantum yield initially decreases with decreasing thickness due to enhanced surface carrier recombination, but sharply increases afterwards. Furthermore, black phosphorus exhibits a much lower surface carrier recombination velocity compared to other semiconductors.
NATURE NANOTECHNOLOGY
(2023)
Article
Energy & Fuels
Ugochi Chime, Leon Wolf, Viktoriia Buga, Daniel Weigand, Alaaeldin Gad, Julian Koehler, Andreas Lambertz, Weiyuan Duan, Kaining Ding, Tsvetelina Merdzhanova, Uwe Rau, Oleksandr Astakhov
Summary: Theoretical predictions estimate that thinner silicon wafers may improve efficiency, with open-circuit voltage increasing and fill factor decreasing as wafer thickness decreases. Experimental results show a broad range of high efficiency under 1 sun for wafer thicknesses ranging from 75 to 170 mu m, with the maximum efficiency of 22.3% obtained at 75 mu m. Thinner wafers also show slightly better efficiency at lower light intensity under sun and LED illumination.
Article
Energy & Fuels
Archana Sinha, Jiadong Qian, Stephanie L. Moffitt, Katherine Hurst, Kent Terwilliger, David C. Miller, Laura T. Schelhas, Peter Hacke
Summary: Degradation from ultraviolet radiation has become prevalent in the front of solar cells due to the use of UV-transmitting encapsulants. This study examines UV-induced degradation in various commercial crystalline silicon cell technologies and finds that modern cell architectures are more vulnerable to UV damage, leading to a significant decrease in power. Bifacial cells with rear-side exposure show a greater power decrease, indicating that the rear side is more susceptible to UV damage.
PROGRESS IN PHOTOVOLTAICS
(2023)
Article
Engineering, Electrical & Electronic
Halubai Sekhar, Tetsuo Fukuda, Tomohiro Kubota, Mohammad Maksudur Rahman, Hidetaka Takato, Michio Kondo, Seiji Samukawa
Summary: This study introduces a new damage-free neutral beam etching technique for transferring resist patterns to silicon wafers. By introducing SF6 gas, the etching rate and profiles were improved, resulting in a significant reduction in surface reflection to 3.7%.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Energy & Fuels
Mohamed Omer, Xizu Wang, Xiaohong Tang
Summary: This study introduces an approach for identifying the dominant recombination pathways in perovskite solar cells (PSCs) by using illumination-side-dependent impedance spectroscopy. The technique is validated and applied experimentally, providing a detailed understanding of performance bottlenecks and losses in PSC devices. This approach can help improve the optimization strategy of PSCs to enhance their performance.
PROGRESS IN PHOTOVOLTAICS
(2022)
Article
Multidisciplinary Sciences
Kie Young Woo, Hyun Gyu Song, Kwanjae Lee, Young Chul Sim, Yong-Hoon Cho
Summary: We propose a key factor associated with the surface recombination velocity and radiative efficiency of an LED, which can estimate its chip size-dependent efficiency. We verify the validity of this factor through experimental comparison of different LED wafers. We examine the efficiencies of micro-LEDs from blue and two green LED wafers through temperature-dependent photoluminescence experiments and extract surface recombination velocities from chip size-dependent time-resolved photoluminescence results. We also provide possible explanations for the different properties of the two green wafers. With the suggested factor, we can predict the chip size-dependent efficiency of an LED wafer more accurately.
SCIENTIFIC REPORTS
(2022)
Article
Energy & Fuels
David Kiermasch, Mathias Fischer, Lidon Gil-Escrig, Andreas Baumann, Henk J. Bolink, Vladimir Dyakonov, Kristofer Tvingstedt
Summary: The photovoltaic perovskite research community has developed a variety of tools and techniques to improve power conversion efficiency. One effective method is using postannealing to increase the open-circuit voltage, which leads to a substantial improvement in efficiency.
Article
Chemistry, Multidisciplinary
Ken Yaegashi, Katsuaki Sugawara, Takemi Kato, Takashi Takahashi, Takafumi Sato
Summary: In this study, the selective fabrication of two different types of ultrathin Bi films, bismuthene and alpha-Bi, on hydrogen-terminated SiC(0001) was achieved by combining the molecular-beam-epitaxy method and low-temperature and low-pressure hydrogen chemical etching of SiC. The bismuthene showed a massive Dirac cone, indicating it as a 2D topological insulator, while alpha-Bi demonstrated an insulating behavior with a large band gap. The mechanism underlying the selective fabrication was discussed in terms of hydrogen desorption from the substrate.
Article
Energy & Fuels
Naeimeh Mozaffari, The Duong, M. M. Shehata, Anh Dinh Bui, Huyen T. Pham, Yanting Yin, Y. Osorio Mayon, Jianghui Zheng, Md Arafat Mahmud, Grace Dansoa Tabi, Gunther G. Andersson, Lachlan E. Black, Jun Peng, Heping Shen, Thomas P. White, Klaus Weber, Kylie R. Catchpole
Summary: Dimensional engineering technique is an efficient method to improve the performance of perovskite solar cells. This study presents a passivation approach for the perovskite/hole transport layer interface using a mixture of guanidinium and n-octylammonium cations. The dual-cation passivation layer provides higher voltage and efficiency, as well as better stability, with a more hydrophobic and smoother surface.
Review
Chemistry, Multidisciplinary
Zhihao Zhang, Lu Qiao, Ke Meng, Run Long, Gang Chen, Peng Gao
Summary: Lead halide perovskite solar cells have achieved significant progress in efficiency and stability. This review discusses various passivation strategies to address the challenges of defects, charge recombination, and stability in perovskite materials. The article also highlights the need for advanced characterization techniques to understand the mechanisms behind the passivation strategies, and proposes future research directions.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Energy & Fuels
Andreas Wolf, Julian Egle, Sebastian Mack, Hannes Hoffler, David Herrmann, Sabrina Lohmuller, Joerg Horzel, Andreas Fell
Summary: This study focuses on the effective surface recombination velocity of alkaline textured, Phosphorus-diffused, and thermal SiO2/SiNx passivated surfaces with an emphasis on the impact of the thermal oxidation temperature. By applying a recent calibration procedure for carrier lifetime measurements, precise determination of the dark saturation current density was achieved. Experimental results from various diffusion/oxidation process combinations provide a dataset for revising the parameterization of the effective surface recombination velocity and investigating the impact of oxidation temperature on passivation quality, including the modeling of fixed surface charges.
SOLAR ENERGY MATERIALS AND SOLAR CELLS
(2021)
Article
Chemistry, Multidisciplinary
Jian Lin, Hongsub Jee, Jangwon Yoo, Junsin Yi, Chaehwan Jeong, Jaehyeong Lee
Summary: The effects of H2S passivation on the effective minority carrier lifetime of crystalline silicon wafers were studied. The highest gain in minority carrier lifetime, up to 2030%, was observed at an annealing temperature of 600 degrees C. X-ray photoelectron spectroscopy analysis indicated that sulfur passivation eliminated dangling bonds on the silicon wafer surface, resulting in the increase in minority carrier lifetime.
APPLIED SCIENCES-BASEL
(2021)
Article
Physics, Applied
I. R. Hooper, E. Khorani, X. Romain, L. E. Barr, T. Niewelt, S. Saxena, A. Wratten, N. E. Grant, J. D. Murphy, E. Hendry
Summary: In this paper, a new type of silicon-based metamaterial with a tunable electron-hole lifetime is designed, achieved by periodically patterning a dielectric surface passivation layer. The application of these metamaterials as photomodulators is investigated, with switching times depending on photoexcitation intensity, wafer thickness, and carrier lifetime.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Chemistry, Physical
Christian M. Wolff, Sean A. Bourelle, Le Quang Phuong, Jona Kurpiers, Sascha Feldmann, Pietro Caprioglio, Jose Antonio Marquez, Jakob Wolansky, Thomas Unold, Martin Stolterfoht, Safa Shoaee, Felix Deschler, Dieter Neher
Summary: This study investigated carrier dynamics in mixed halide perovskite solar cells with an efficiency >20%, revealing a superposition of first-, second-, and third-order recombination processes. The results show that under solar illumination, recombination in the studied solar cells proceeds predominantly through nonradiative first-order recombination with a lifetime of 250 ns. The transient experiments further help explain the steady-state solar cell properties over a wide range of illumination intensities.
ADVANCED ENERGY MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
David A. Valverde-Chavez, Esteban Rojas-Gatjens, Jacob Williamson, Sarthak Jariwala, Yangwei Shi, Declan P. McCarthy, Stephen Barlow, Seth R. Marder, David S. Ginger, Carlos Silva-Acuna
Summary: Through ECPL spectroscopy, the role of surface passivation in carrier trapping and nonlinear recombination dynamics in hybrid metal-halide perovskites was investigated. Passivation was found to have a direct impact on both shallow and deep traps, with passivation of deep traps increasing carrier lifetimes and passivation of shallow traps reducing the excitation density required for saturation. The study demonstrates the ability of ECPL to provide detailed information on the passivation of shallow traps beyond conventional time-resolved photoluminescence techniques.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
