An interdiffusion-controlled nucleation strategy for efficient sequential deposition of perovskite photovoltaics

Abstract

The sequential deposition route is widely investigated in fabricating perovskite thin films for state-of-the-art perovskite photovoltaics. However, concerns such as lower morphological control, phase purity, and remnant unreacted salts such as methylammonium iodide (MAI) and PbI₂ are raised, which can significantly deteriorate the optoelectronic properties and hence the operational durability of the devices. In this work, we developed a new interdiffusion-controlled nucleation (ICN) strategy by introducing sulfamic acid agents to improve the sequential deposition of perovskite crystals, achieving low defect density and high-quality perovskite films. Precisely, the ICN strategy can be used to tune the dense PbI₂ films into a porous morphology, which promoted the adequate conversion of perovskite and reduced the residual PbI₂. Owing to the enhanced crystallization of the perovskite films and passivated surface defects, we obtained a summit PCE exceeding 23% for perovskite solar cells and achieved responsivity values of up to 0.49 A W⁻¹ with linear dynamic ranges of up to 136.75 dB for perovskite photodetectors. The ICN strategy provides a simple and effective way to improve the performance of perovskite-based photovoltaic devices.