Toward ultra-low reflectance semi-transparent organic photovoltaic cells with biomimetic nanostructured transparent electrode

Semi-transparent organic photovoltaic cells (STOPVs) hold the great potential as a solar conversion source installed on the glass curtain walls. The cell performance of STOPVs is to some extent balanced among the absorption, transmission and reflection of the incident solar radiation. For the practical application with a defined transparency, the efficiency of STOPVs can be optimized by maximizing the light absorption as well as minimizing the reflection that contribute to the light pollution. Herein, a low-reflectance STOPV is presented with relatively high efficiency, high transmittance, and suitable color rendering property. A 15.9% increase in photocurrent and a 28% decrease in reflection are realized with the implementation of biomimetic moth-eye nanostructures into the dielectric-metal-dielectric transparent electrodes. For an optimized PTB7:PC₇₁BM-based STOPV on flexible plastic substrate, the average transmittance in the visible region is kept at 46.1% and the average reflectance is reduced to 10.3%, leading a power conversion efficiency of 3.4%. The pathway described here is promising for opening up opportunities of reliable STOPVs towards the future commercial applications.