Enhancement in power conversion efficiency and stability of perovskite solar cell by reducing trap states using trichloroacetic acid additive in anti-solvent

Abstract

Perovskite solar cells (PSCs) have shown significant commercial promise due to their fast development over the last decade and recent demonstration of a power conversion efficiency (PCE) almost equivalent to that of silicon-based solar cells. Shallow carrier trapping states within the bulk or surface of a perovskite layer are highlighted by researchers as a reason for the PSC efficiency losses. Suppressing the trap-induced shallow defects is a powerful strategy to improve the potential of perovskite materials for solar cell application. The current study planned on tailoring chlorobenzene (CB) anti-solvent with a trichloroacetic acid (TCAA) additive to prepare a favourable MAPbI3 layer with lower defects to record higher power conversion efficiency (PCE) in MAPbI3-based solar cells. Characterization results indicate the introduction of a few amounts of TCAA into CB affects the perovskite crystallization through reactions of the carboxyl group with the under-coordinated lead ions during the fabrication process. The TCAA-based PSCs show lower radiative and non-radiative charge recombination, leading to facilitated charge transport within the PSCs. It produces a champion PCE of 19.37% for the TCAA-based PSCs with a boosted stability behavior, which is greater than the control PSCs, which have a maximum PCE of 16.90%.