Enhance and balance AVT and PCE of the semi-transparent perovskite solar cells for BIPV via grating-based photonic crystals

Semi-transparent perovskite solar cells attract significant attention in building-integrated photovoltaics, especially for solar window application. However, thinning the perovskite photoactive layer, setting up nanostructures in the perovskite layer, and improving the functional layer transparent can neither effectively balance the power conversion efficiency (PCE) and average visible transmittance (AVT), nor can it effectively resolve the issue of colorful transmitted light. Here, based on the light polarization-selective absorption characteristics of photonic crystals, a semi-transparent perovskite solar cell with the grating-based photonic crystals is presented. It can apply the original layer structure of high efficiency perovskite solar cells without any transparent replacement, including the retention of opaque electrodes. Through the developed multiphysics and multi-objective mathematical model, the semi-transparent FAPbI3 solar cells can be optimized with PCE of 10% and AVT of 60.3%. When PCE increases to 12%, 15%, and 17%, the corresponding AVTs are 52.6%, 41.1%, and 33.4%, respectively. The performance far exceeds the benchmark of PCE (10%) and AVT (25%) for solar window application. Also, the transmitted light remains white regardless of the values of AVT and PCE. Furthermore, the semi-transparent perovskite solar cells with the grating-based photonic crystals can exhibit stable high-performance when the dimension tolerance varies from 1% to 20%, which reduces the requirement of processing technology. In the end, a design and optimization guideline for the semi-transparent perovskite solar cells is proposed through the analyses on the effect of a broad incident angle. These findings provide effective design strategies for the semi-transparent perovskite solar cells in the context of building-integrated photovoltaics.