Ion–Dipole Interaction Enabling Highly Efficient CsPbI₃ Perovskite Indoor Photovoltaics

Abstract

Metal halide perovskites are ideal candidates for indoor photovoltaics (IPVs) because of their easy-to-adjust bandgaps, which can be designed to cover the spectrum of any artificial light source. However, the serious non-radiative carrier recombination under low light illumination restrains the application of perovskite-based IPVs (PIPVs). Herein, polar molecules of amino naphthalene sulfonates are employed to functionalize the TiO₂ substrate, anchoring the CsPbI₃ perovskite crystal grains with a strong ion-dipole interaction between the molecule-level polar interlayer and the ionic perovskite film. The resulting high-quality CsPbI₃ films with the merit of defect-immunity and large shunt resistance under low light conditions enable the corresponding PIPVs with an indoor power conversion efficiency of up to 41.2% (P_in : 334.11 µW cm^-2 , P_out : 137.66 µW cm^-2 ) under illumination from a commonly used indoor light-emitting diode light source (2956 K, 1062 lux). Furthermore, the device also achieves efficiencies of 29.45% (P_out : 9.80 µW cm^-2 ) and 32.54% (P_out : 54.34 µW cm^-2 ) at 106 (P_in : 33.84 µW cm^-2 ) and 522 lux (P_in : 168.21 µW cm^-2 ), respectively.