The Effect of Non-Uniform Irradiation on Laser Photovoltaics: Experiments and Simulations

Abstract

Laser wireless power transmission (LWPT) has various applications for mobile devices and specific equipment under extreme conditions. The light spot received by laser photovoltaics is usually non-uniform, resulting in system efficiency reduction. The output characteristics of 1 × 1 cm2 GaAs laser photovoltaics were measured under various illuminated areas. The experimental results showed that the efficiency decreased from 40.8% at the full irradiated area to 26.7% at 1/10 irradiated area. Furthermore, the drop in short-circuit current was the main factor for decreasing the efficiency. A three-dimensional (3D) finite element model was used to investigate this factor. The simulation results indicated that non-uniform irradiation could increase the total non-radiative recombination rate. The recombination rate of the absorption region increased from 6.0 × 1020 cm−3/s to 2.5 × 1021 cm−3/s, reducing the short-circuit current.