Surface passivation using organic dipole rotation enables 40.9 % indoor efficiency in perovskite solar cells

Abstract

Background: The strategy of passivating interfacial defects in perovskite solar cells (PSCs) has recently attracted significant attention for its demonstrated potential to enhance device performance. Selecting perovskite materials with optimal bandgaps and low defect densities is crucial for maximizing photon absorption, reducing recombination losses, and achieving superior power conversion efficiencies (PCE) under indoor lighting conditions. Method: In this study, we presented a p-i-n PSC introduced 2-phenylethylamine hydroiodide (PEAI) as a multifunctional passivator. Atomic-force microscopy (AFM) images, X-ray diffraction (XRD) patterns, photoluminescence (PL) spectra, time-resolved PL curves, and Raman scattering spectra collectively reveal that both pre-treatment and post-treatment with PEAI play a critical role in the formation of merged perovskite grains and controlling the rotation of organic dipoles in the upper portion of the perovskite layers. Significant findings: The merged grains, with defect passivation facilitated by PEAI, significant enhanced the performance of the inverted Cs0.18FA0.82PbI3 PSC, boosting its efficiency from 16.51 % to 20.98 % under one-sun illumination. The optimized strategy demonstrated remarkable results in wide-bandgap perovskites, achieving an impressive performance of 40.9 % under indoor 3000 K LED lighting, with a fill factor of 81.3 +/- 0.1 %. These findings highlight a promising avenue for advancing the photovoltaic performance of formamidinium-based PSCs under both standard sunlight and indoor lighting conditions.