Novel Two-Dimensional Graphdiyne-Derived Additive for Stable Inverted Perovskite Solar Cells

Abstract

The defects in perovskite films hinder the improvement of efficiency and long-term device stability of perovskite solar cells (PSCs). Antisolvent additive engineering has been widely applied to effectively reduce perovskite defects and improve the perovskite crystal quality. However, most of the traditional antisolvent-assisted organic additives endure the disadvantages of high volatility, instability, inflammability, high diffusion coefficient, and even toxicity, which hinder the device’s stability for PSCs and raise serious environmental concerns. Herein, in this work, a novel two-dimensional tripolyindene hydrogen-substituted graphdiyne, denoted as DES-O-PHsGY, was synthesized through an easily accessible and biocompatible deep eutectic solvent. XPS measurement demonstrated that DES-O-PHsGY can passivate the lead defects in the perovskite layer. XRD and SEM results verified that DES-O-PHsGY can improve perovskite crystallization. After DES-O-PHsGY was applied as an antisolvent additive for MAPbI3-based PSCs, the maximum open-circuit voltage of devices was increased from 1.079 V to 1.106 V, accompanied by a maximum power conversion efficiency of 20.51% surpassing that without the additive (19.51%). More importantly, the perovskite film with DES-O-PHsGY modification showed satisfactory thermal stability under an 80 °C continuous heating process. This work provides a novel method to prepare effective additives for perovskite defect passivation.