Semi-transparent polymer solar cells with optical adjusting layers

Abstract

Efficiency and transparency are the most essential issues for semi-transparent polymer solar cells (ST-PSCs), and must be compatible to facilitate and advance commercial applications such as photovoltaic integration in windows, roofs and other aesthetic buildings. Herein, an optical adjusting layer (OAL) is intentionally introduced to poly(3-hexylthiophene) (P3HT): indene-C₆₀ bisadduct (ICBA)-based ST-PSCs to effectively enhance light absorption by adjusting the incident light phase. The shoulder field of the incident photon-to-electron conversion efficiency (IPCE) spectra was greatly broadened, especially at long wavelengths, resulting in a 22.6% improvement in power conversion efficiency (PCE) while maintaining a 26.1% average visible transmittance (AVT). Furthermore, transfer matrix modeling (TMM) was used to analyze the function of the OAL by calculating the optical field distribution and absorption in the device. The reflection phase shift induced optical field redistribution results in dramatically enhanced absorption in the active layer, which agrees well with experimental results. We believe these findings offer a promising path to develop high-performance ST-PSCs with practical applications.