Modulating Crystallization and Defect Passivation by Butyrolactone Molecule for Perovskite Solar Cells

Abstract

The attainment of a well-crystallized photo-absorbing layer with minimal defects is crucial for achieving high photovoltaic performance in polycrystalline solar cells. However, in the case of perovskite solar cells (PSCs), precise control over crystallization and elemental distribution through solution processing remains a challenge. In this study, we propose the use of a multifunctional molecule, α-amino-γ-butyrolactone (ABL), as a modulator to simultaneously enhance crystallization and passivate defects, thereby improving film quality and deactivating nonradiative recombination centers in the perovskite absorber. The Lewis base groups present in ABL facilitate nucleation, leading to enhanced crystallinity, while also retarding crystallization. Additionally, ABL effectively passivates Pb2+ dangling bonds, which are major deep-level defects in perovskite films. This passivation process reduces recombination losses, promotes carrier transfer and extraction, and further improves efficiency. Consequently, the PSCs incorporating the ABL additive exhibit an increase in conversion efficiency from 18.30% to 20.36%, along with improved long-term environmental stability. We believe that this research will contribute to the design of additive molecular structures and the engineering of components in perovskite precursor colloids.

Recent trends on the application of phytochemical-based compounds as additives in the fabrication of perovskite solar cells

“…groups (-NH 2 and CQO) and hydrophobic nature of the ABL additive respectively terminated the Pb 2+ dangling bond and reduced moisture ingress in the film, leading to a reduction in non-radiative recombination power losses and moistureinduced degradation in the resulting PSC device. 74,82 As such, additive engineering has therefore played a central role in the efforts to synergistically improve the PCE, stability, and reproducibility of PSCs. 83 A comprehensive review on additive engineering and its important role in PSCs has been given by Li et al, 59 Zhang & Zhu, 84 and Mahapatra et al, 85 and recently updated by Pereyra et al 74 Recent trends in the use of additives in PSCs have shifted towards the use of natural products owing to their ecofriendliness, biocompatibility, availability, and low cost when compared to their synthetic counterparts.…”