Simulation of Thin-Film Cells With a Multiscale Quantum-Mechanical/Electromagnetic Method

This article studies the surface plasmon-enhanced effect of metal nanoparticles (NPs) in thin-film cells by using a semi-classical multiscale quantum-mechanical/electromagnetic (QM/EM) method. The QM/EM method establishes a relationship between classical electromagnetic environment and full quantum-mechanical photovoltaics with quantized vector magnetic potential on the boundary. In our theoretical framework, the EM region is solved by Maxwell equation with method of moments (MoM), and the QM region is solved by density-functional tight-binding (DFTB) theory with the nonequilibrium Green's function. The proposed method has predicted that metal NPs could generate surface plasmon enhancement and substantially improve the photovoltaic performance of thin-film cells. By comparison, we investigated the influences of different NP materials, distributions and drop-casting ratios on the current-voltage characteristics. The simulated results provide a comprehensive understanding of photoelectric interaction, which can be utilized to improve the power conversion efficiency (PCE) of thin-film cells by fast optimization design.