Highly efficient CsPbIBr2 perovskite solar cells with efficiency over 9.8% fabricated using a preheating-assisted spin-coating method

Considering both the features of bandgap and stability, CsPbIBr2 presents a promising potential among the inorganic perovskite photovoltaic materials. Nevertheless, the poor quality films derived from the precursor solution acutely hinders the performance improvement of cells. Herein, high-quality CsPbIBr2 perovskite films are effectively fabricated through a facile one-step spin-coating method assisted by a preheating process. During spin coating, the reserved substrate heat accelerates solvent molecule volatilization, resulting in the complete coverage and enhanced crystallinity of the CsPbIBr2 films. Upon optimizing the substrate-preheating temperature precisely, perovskite solar cells (PSCs) with a configuration of ITO/SnO2/CsPbIBr2/spiro-OMeTAD/Ag exhibit a superior power conversion efficiency (PCE) of 9.86% with a stabilized output of 8.78% and an open-circuit voltage (V-oc) of 1.267 V, all of which represent the excellent properties of the pure CsPbIBr2-based cells. Moreover, this work provides a promising route for the fabrication of inorganic perovskites.