Modulating hot carrier dynamics is crucial in tin halide perovskite photovoltaics, particularly under indoor illumination with limited photon flux. Herein, a fullerene derivative bearing four piperazine groups (denoted as TPPC) is synthesized to engineer the perovskite/C60 interface. The TPPC molecule exhibits a dipole moment of 1.97 Debye, leading to enhanced adsorption energy on perovskite surface and robust interfacial interaction. The newly formed surface dipole optimizes the interfacial energy level alignment via a cascade gradient, enabling modulation of interfacial hot carrier dynamics. Consequently, TPPC-treated photovoltaic devices achieve a champion power conversion efficiency (PCE) of 22.49% and a maximum output power density (Pout) of 64.1 μW cm-2 under white light-emitting diode illumination (3000 K, 1000 lux, 285 μW cm-2). Large-area (1.21 cm2) devices attain a PCE of 17.94% (certified: 15.93%) and a maximum Pout of 51.2 μW cm-2 under the same illumination conditions.
Xiao et al. (Wed,) studied this question.