Society of Photo-Optical Instrumentation Engineers (SPIE)
Proceedings of SPIE 9358, Physics, Simulation, and Photonic Engineering of Photovoltaic Devices IV
Photon absorption is a primary cause of limited solar cell performance. A proposed solution is investigated in this paper through modeling and simulation of a hybrid multi-junction silicon (HMJ-Si) solar cell. HMJ-Si cells, which are stacked silicon solar cells with an insulating air gap between them, were designed with front and rear metal grating geometries that exploit interference patterns for enhanced light management. Interference patterns were investigated in MATLAB® by using the Rayleigh-Sommerfeld formula to model 31 distinct wavelengths from 800-1100nm. Also incorporated in the model were plane wave tilts from -0.005 to 0.005 radians to account for the maximum angle of light subtended by the sun. The exploration of various grating geometries showed that contact widths of 400μm spaced 900μm apart provided an optimal destructive interference pattern while maintaining a 69.2% throughput. This contact grating was selected for finite-difference time-domain (FDTD) analysis using Lumerical® FDTD Solutions. The resulting far-field projection verified that the destructive interference pattern reaches the bottom cell with negligible fringing effects. Further analysis of the data led to a nominal bottom cell front contact width of 200μm spaced 1100μm apart.