High-performance wide-bandgap perovskite solar cells with an enhanced photon-to-electron response of near-infrared wavelengths

Abstract

Wide-bandgap perovskite solar cells (PSCs) have been intensively investigated owing to their strong light absorption of short wavelengths and high open-circuit voltage. In this study, we improved the performance of wide-bandgap (1.74 eV) PSCs by incorporating a non-fullerene acceptor of Y6 into a Cs_0.12MA_0.05FA_0.83Pb(I_0.6Br_0.4)₃ perovskite film, which could enhance the photon-to-electron response at near-infrared wavelengths. Due to the Lewis-base groups, inserting Y6 could effectively passivate the vacancy-induced defects in the perovskite film, which further facilitated the charge transport of the PSCs. As a result, the power-conversion-efficiency (PCE) of the wide-bandgap PSCs was significantly improved from 17.6% to 19.8% (on average), which was mainly induced by the conspicuously enlarged short-circuit current density. With the introduction of Y6, the long-term stability of the PSCs (without encapsulation) was simultaneously enhanced with the PCE degradation significantly decreased from 33.5% to 16.7% after a duration of 15 days. The best PSC with Y6 exhibited a highest PCE of 20.2%, with a stable power output and negligible hysteresis. The results of this research demonstrate the superior effect of Y6 on boosting the performance of wide-bandgap PSCs.