Colorful flexible perovskite solar cells based on tin oxide nanobowl arrays

Abstract

Colorful perovskite solar cells (PSCs) with aesthetic functionalities are of significant interest to building-integrated photovoltaics and wearable electronics. However, it remains challenging to develop high-efficiency, flexible PSCs with customizable colors. Here, we developed a facile and effective technique for the low-temperature fabrication of tin oxide (SnO2) nanobowl (NB) arrays on different transparent conductive substrates. The ordered SnO2 NB array not only exhibited angle-dependent structural colors as 2D photonic crystals, but also contributed to the improvement of the photovoltaic performance due to their excellent light harvesting and charge extraction capability. As a result, the colorful PSCs using the SnO2 NB array as the electron transport layer on the fluoride-doped tin oxide substrate achieved a power conversion efficiency (PCE) as high as 20.44%. Furthermore, the low-temperature processed SnO2 NB array was adapted to fabricate unique colorful flexible PSCs on the polyethylene naphthalate/indium tin oxide substrate, yielding a remarkable PCE of 18.21% with vivid colors and good mechanical stability toward bending. This work opens a new bioinspired avenue toward highly efficient, colorful photovoltaics including colorful flexible PSCs.