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Influence of the energy dependence of the absorption coefficient on the solar energy conversion efficiency
摘要： In most cases, when the ef?ciencies of a single or multi-gap (with intermediate bands) solar cell are evaluated, the energy dependence of the absorption coef?cients is ignored. In this work we will evaluate the range of optical thickness and average absorption coef?cients in which this dependence should be considered. For this study we use different absorption coef?cients generated randomly as a function of the energy. In many practical cases, the ef?ciencies are lower than those expected.
关键词： optical thickness,energy dependence,intermediate-band solar cells,solar energy conversion efficiency,absorption coefficient
更新于2025-09-23 15:21:21
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Optimized Operation of Quantum-Dot Intermediate-Band Solar Cells Deduced from Electronic Transport Modeling
摘要： Study of the physics of quantum electronic transport has not tackled the problems raised by quantum-dot intermediate-band solar cells. Our study shows that this physics imposes design rules for the intersubband transition. We develop an analytical model that correctly treats, from a quantum point of view, the trade-off between the absorption, the recombination, and the electronic transport occurring in this transition. Our results clearly indicate that it is essential to control the transit rate between the excited state of the quantum dot and the embedding semiconductor. For that, we propose assuming the dot in a tunnel shell whose main characteristics can be obtained by a simple analytical formula. Moreover, we show that in a realistic case, the energy transition needs to be larger than only 0.27 eV to obtain a quasi-Fermi-level-splitting. This quite small value designates the quantum-dot solar cell as a serious candidate to be an efficient intermediate-band solar cell. This work gives a framework to design efficient intersubband transitions and opens new opportunities for quantum-dot intermediate-band solar cells.
关键词： quantum-dot,intersubband transition,electronic transport modeling,intermediate-band solar cells,quasi-Fermi-level-splitting
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Ottawa, ON, Canada (2019.7.8-2019.7.12)] 2019 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD) - Wurtzite InGaN/GaN Quantum Dots for Intermediate Band Solar Cells
摘要： Wurtzite InGaN quantum dots in GaN are investigated for intermediate band solar cells. A global limiting power conversion ef?ciency of 44% is predicted through detailed balance calculations with full freedom of allowed subgap transitions. We consider cylindrical quantum dots, predicting band structures using an 8-band k.p model, including deformation potential and piezoelectric ?elds from induced lattice strain. Taking the energy levels from the k.p model as absorption cutoffs in the detailed balance calculation, we determine the best device ef?ciency possible as a function of indium fraction and dot size. For small dots, of size ≈ 50 ?A and indium fraction ≈ 0.7, ef?ciencies up to 42% are in principle attainable under 1-sun illumination.
关键词： Quantum Dots,Intermediate Band Solar Cells,Detailed Balance Calculations,8-band k.p model,Wurtzite InGaN
更新于2025-09-11 14:15:04
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Fabrication of in-situ Ti-doped CuGaS2 thin films for intermediate band solar cell applications by sputtering with CuGaS2:Ti targets
摘要： Intermediate band solar cells (IBSCs) have great potential for improving device efficiencies, which can be fabricated by doping appropriate elements into a matrix semiconductor with a high band-gap (Eg). CuGaS2 (CGS) is an absorber with high absorption coefficient and high Eg, which is suitable to be a matrix. And some transition metals are suitable doping elements. Here, in-situ Ti-doped CGS thin films were deposited by sputtering CuGaS2:Ti targets to prepare IBSCs. The targets were fabricated by hot-pressed sintering of ball-milled Cu2S, Ga2S3, and TiS2 mixed powders. In-situ Ti-doped precursor films were prepared by sputtering with these targets. After sulfurization, grains grew up and CGS phases were gained. The Ti atoms were successfully doped into the CGS lattices. The Eg of about 2.42 eV was consistent with CGS. The current density-voltage curve of the solar cell exhibited exponential characteristics. This approach has enormous promise for the preparation of IBSCs.
关键词： In-situ doping,Intermediate band solar cells,CuGaS2:Ti targets,Sputtering,Solar energy materials
更新于2025-09-11 14:15:04
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Computational screening of bulk materials with intrinsic intermediate band
摘要： Intermediate band compounds are promising high-efficiency materials for solar cells. Besides that, they also show unusual properties that make them interesting from a fundamental point of view. In this work, we create a series of filters capable of searching the AFLOW-ICSD materials database for compounds that show intrinsic intermediate bands. We analyse all available binary and ternary compounds, totaling 45,656 entries. The selected materials show at least one narrow band (maximum width of 1 eV) next to the energy gap. After removal of repeated entries and of wide bandgap insulators, we end up with a total of 660 materials that present intermediate bands. From this group, the majority has completely empty or filled intermediate bands or, during new calculations, changed to another state with a different type of intermediate band or no band of this type. Nevertheless, three compounds fulfill all criteria and continue to present a partially filled intermediate band (Bi2Rh2O7, Ca5FeN6, and OsTb6I10), showing potential for solar cells applications.
关键词： Intermediate band,Solar cells,Materials screening,High-throughput screening,DFT calculations
更新于2025-09-10 09:29:36