Coupled optical and electrical modeling of thin-film amorphous silicon solar cells based on nanodent plasmonic substrates

Abstract

Advanced light managements on nanostructured substrates have delivered outstanding optical absorption enhancement for high performance solar cells. In this work, thin-film amorphous silicon (a-Si:H) solar cell with efficient light trapping capability was constructed on the nano-patterned back reflector. In order to investigate the fundamental properties of the nano-patterned solar cell, the spatial distributions of electrical properties in silicon absorption layers are simulated by a coupled optical and electrical modeling method. The current density and electric field distribution under different bias voltages are compared. While the patterned device shows much higher short circuit current density, the open circuit voltage (VOC) is lower than its counterpart. In nanostructured device, the relatively weak electric field is preferred to be localized in the top corners, where a local current reversal will occur and lead to the reduction of VOC. An increasing doping concentration in p-layer promotes the internal electric field as well as the corresponding short circuit current and open circuit voltage. This work provides guidelines for rational design of light harvesting nanostructure for high performance thin film solar cells.