A first-principles plane wave method with the ultrasoft pseudopotential scheme in the frame of the density functional theory （DFT） is performed to calculate the lattice parameters a and c, the bulk modulus B0 and it...A first-principles plane wave method with the ultrasoft pseudopotential scheme in the frame of the density functional theory （DFT） is performed to calculate the lattice parameters a and c, the bulk modulus B0 and its pressure derivative B0 of the zinc-blende GaAs （ZB-GaAs）, rocksalt GaAs （RS-GaAs）, CsCl-GaAs, NiAs- GaAs and wurtzite GaAs （WZ-GaAs）. Our results are consistent with the available experimental data and other theoretical results. We also calculate the phase transition pressures among these different phases. The results are satisfactory.展开更多
The record efficiency for a thin-film, single-junction solar cell has remained static at 28.8% since 2012. This research presents a unique design that demonstrates potential to exceed record efficiency and approach th...The record efficiency for a thin-film, single-junction solar cell has remained static at 28.8% since 2012. This research presents a unique design that demonstrates potential to exceed record efficiency and approach the theoretical efficiency limit of ~33.5%. The findings of this study are significant, from an efficiency standpoint, and also because the cell design can be realized using existing fabrication methods that do not require complex, post-processing steps. In this study, a benchmark simulation is developed that closely resembles a high-efficiency, front-and-back contact cell. Intrinsic performance limiters are overcome by moving the emitter and front-contact to the back of the cell to eliminate electrical grid shading and improve optical performance. To further improve performance, the P-N junction formed by the emitter layer is removed from the model to allow selective Ohmic contacts to accept (reject) minority (majority) carriers as required. The design modifications improve open-circuit voltage, short-circuit current, and fill-factor which collectively boost efficiency above 30%-primarily due to a 2% gain of incident irradiance and improved optical performance.展开更多
This research builds upon the authors’ previous work that introduced and modeled a novel Gallium-Arsenide, Emitterless, Back-surface Alternating Contact (GaAs-EBAC) thin-film solar cell to achieve >30% power conve...This research builds upon the authors’ previous work that introduced and modeled a novel Gallium-Arsenide, Emitterless, Back-surface Alternating Contact (GaAs-EBAC) thin-film solar cell to achieve >30% power conversion efficiency. Key design parameters are optimized under an Air-Mass (AM) 1.5 spectrum to improve performance and approach the 33.5% theoretical efficiency limit. A second optimization is performed under an AM0 spectrum to examine the cell’s potential for space applications. This research demonstrates the feasibility and potential of a new thin-film solar cell design for terrestrial and space applications. Results suggest that the straight-forward design may be an inexpensive alternative to multi-junction solar cells.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10776022, 10576020, and 60436010.
文摘A first-principles plane wave method with the ultrasoft pseudopotential scheme in the frame of the density functional theory （DFT） is performed to calculate the lattice parameters a and c, the bulk modulus B0 and its pressure derivative B0 of the zinc-blende GaAs （ZB-GaAs）, rocksalt GaAs （RS-GaAs）, CsCl-GaAs, NiAs- GaAs and wurtzite GaAs （WZ-GaAs）. Our results are consistent with the available experimental data and other theoretical results. We also calculate the phase transition pressures among these different phases. The results are satisfactory.
文摘The record efficiency for a thin-film, single-junction solar cell has remained static at 28.8% since 2012. This research presents a unique design that demonstrates potential to exceed record efficiency and approach the theoretical efficiency limit of ~33.5%. The findings of this study are significant, from an efficiency standpoint, and also because the cell design can be realized using existing fabrication methods that do not require complex, post-processing steps. In this study, a benchmark simulation is developed that closely resembles a high-efficiency, front-and-back contact cell. Intrinsic performance limiters are overcome by moving the emitter and front-contact to the back of the cell to eliminate electrical grid shading and improve optical performance. To further improve performance, the P-N junction formed by the emitter layer is removed from the model to allow selective Ohmic contacts to accept (reject) minority (majority) carriers as required. The design modifications improve open-circuit voltage, short-circuit current, and fill-factor which collectively boost efficiency above 30%-primarily due to a 2% gain of incident irradiance and improved optical performance.
文摘This research builds upon the authors’ previous work that introduced and modeled a novel Gallium-Arsenide, Emitterless, Back-surface Alternating Contact (GaAs-EBAC) thin-film solar cell to achieve >30% power conversion efficiency. Key design parameters are optimized under an Air-Mass (AM) 1.5 spectrum to improve performance and approach the 33.5% theoretical efficiency limit. A second optimization is performed under an AM0 spectrum to examine the cell’s potential for space applications. This research demonstrates the feasibility and potential of a new thin-film solar cell design for terrestrial and space applications. Results suggest that the straight-forward design may be an inexpensive alternative to multi-junction solar cells.
