Enhancing inverted perovskite solar cells via dipole-moment-tuned self-assembled monolayers with efficiency of 25.75%

Abstract

An interface engineering strategy is demonstrated for perovskite solar cells (PSCs) through strategic incorporation of calcium phosphorylcholine chloride (CaPhCl) into self-assembled monolayers (SAMs), achieving remarkable performance enhancement via dual-function interfacial modulation. The large molecular dipole moment of CaPhCl (9.26 D) enables precise energy level alignment at the hole transport interface, while its unique chemical interaction with excess PbI₂ promotes stable α-phase perovskite formation. This synergistic effect simultaneously addresses two critical challenges in PSC development: interface energetics and stability. The optimized devices achieve a power conversion efficiency of 25.75 % with a high open-circuit voltage of 1.19 V, representing one of the highest efficiencies reported for NiO_x-based inverted PSCs. Notably, these devices demonstrate exceptional operational stability, retaining 91 % of their initial efficiency after 1000 h of continuous illumination. Beyond immediate performance gains, this work introduces a new paradigm for interface engineering in perovskite optoelectronics where multifunctional molecular modifiers can simultaneously enhance efficiency and stability, offering a promising pathway toward commercial deployment of high-performance PSCs.