Morphological engineering for high‐performance perovskite field‐effect transistors

Abstract The emergence of perovskite semiconductors for field‐effect transistor (FET) applications has received significant research attention due to their excellent electronic properties. The rapid development of perovskite FETs over the last few years has been driven by advances in understanding the thin‐film morphologies of perovskite layers and their intriguing correlations with charge carrier transport, device performance, and stability. Here we summarize the progress in morphological engineering aimed at improving the electrical parameters of perovskite FETs. We first discuss the mechanisms of crystal nucleation and growth in solution‐processed polycrystalline perovskite thin films, along with their morphological characteristics, including grain boundaries, defects, ionic and charge transport properties. We then elaborate on the impacts of these microstructures on the performance of perovskite FET devices. Representative optimization strategies are also presented, showcasing how fundamental understandings have been translated into state‐of‐the‐art perovskite FETs. Finally, we provide a perspective on the remaining challenges and future directions of optimizing perovskite morphologies, toward an in‐depth understanding of the relationships between film morphology, electrical property and device performance for the next advances in transistor.