Revealing Crystallization Dynamics and the Compositional Control Mechanism of 2D Perovskite Film Growth by In Situ Synchrotron-Based GIXRD

Abstract

Quasi-two-dimensional (2D) perovskites promise the intrinsically stable solar cell performance. However, the crystal orientation and phase distribution in 2D solution processed perovskite are difficult to be manipulated, which restricts the device efficiency as well as its reproducibility. Here, we simply incorporate potassium ion (K +) into quasi-2D precursor solution, which can dramatically change the nucleation steps during perovskite films spin-coating process probed by in-situ synchrotron-based grazing incident X-ray diffraction (GIXRD). It is notable that a desired vertical oriented 2D phase without intermediate compound can be easily formed after spin-coating, which simultaneously reduces the distribution of low dimensional 2D perovskite phases in association with suppressed trap states. Therefore, the power conversion efficiency of doped 10% K + 2D perovskite solar cells can yield up to 11.3% as well as long-term stable performance with high reproducibility. This work paves a key path to control the quasi-2D nucleation and crystallization processing via chemical additives.