Novel Bimodal Silver Nanowire Network as Top Electrodes for Reproducible and High‐Efficiency Semitransparent Organic Photovoltaics

Abstract

Semitransparent organic photovoltaics (ST‐OPVs) provide a potentially facile route for some applications in building integrated photovoltaics. One of the challenges in developing large‐scale, printable ST‐OPVs is to address the need for high‐performance and fully solution‐processed top electrodes, allowing the replacement of the evaporated thin metallic films (Ag, Au, and Al). Silver nanowire (AgNW) is considered a promising candidate for the substitution due to its excellent transparency, conductivity, and solution processability. Herein, a novel bimodal AgNW (AgNW‐BM) electrode is reported, comprising AgNWs of two different aspect ratios. It is shown that the AgNW‐BM film achieves lower sheet resistance and higher visible transmittance than each monodisperse AgNW film, respectively. Furthermore, ST‐OPVs based on PTB7‐Th:IEICO‐4F with AgNW‐BM top electrodes are fabricated, which can obtain a maximum power conversion efficiency (PCE) of 7.49% with an average visible transmittance (AVT) of 33%. The ST‐devices also demonstrate an enhanced reproducibility and excellent color‐rendering index of 90. In addition, the bimodal top electrode is successfully implemented in the PM6:Y6 system with a higher PCE of 9.79% and with an AVT of 23%, demonstrating the universality for various semiconductor systems. Our work provides a simple strategy to realize fully solution‐processed, highly efficient ST‐OPVs.