CsPbBr₃ quantum dots assisted crystallization of solution-processed perovskite films with preferential orientation for high performance perovskite solar cells

The performance of hybrid perovskite solar cells (PSCs) is significantly influenced by the crystallization and morphology of perovskite films. Herein, a novel method of CsPbBr₃ quantum dots (QDs) assisted nucleation is applied to prepare high quality solution-processed methylammonium lead iodide (MAPbI₃) films by employing CsPbBr₃ QDs as an additive into diethyl ether anti-solvent. The appropriate amount of CsPbBr₃ QDs can act as effective heterogeneous nucleation centers, leading to the formation of smooth and pinhole-free perovskite films with increased grain size. Furthermore, the growth direction of MAPbI₃ grains is regulated by CsPbBr₃ QDs, exhibiting preferential orientation of (110) plane. Therefore, the MAPbI₃ films with CsPbBr₃ QDs modification show reduced defects and increased carrier lifetime. As a result, the champion PSC with a maximum power conversion efficiency (PCE) up to 20.17% is achieved and 85% of its initial PCE is maintained after aging 1000 h at room temperature under a relative humidity of 50%. This work demonstrates a feasible way to prepare high quality perovskite films for optoelectronic applications.