Fabrication of [001]‐Oriented FAPbI3‐Based Photodetector With Excellent Air Stability Via Green Anti‐Solvent Additive Engineering

Abstract

AbstractFormamidinium lead triiodide (FAPbI3) exhibits excellent thermal and chemical stability, making it a suitable alternative for methylammonium lead triiodide (MAPbI3) in high‐performance photodetectors. However, FAPbI3 faces the challenge of transforming from the metastable photoactive black phase α‐FAPbI3 to the photoinactive yellow phase δ‐FAPbI3 at room temperature. This phase transition is accelerated in humid atmospheric conditions. To realize high‐performance FAPbI3‐based photodetectors, it is crucial to form stable and highly crystalline phase‐pure α‐FAPbI3 films. Herein, is fabricate highly stable and crystalline FAPbI3 films and photodetectors through anti‐solvent additive engineering (AAE) using a green anti‐solvent (isopropanol, IPA) and an organic spacer (phenethylammonium iodide, PEAI). It is found that PEAI‐AAE treatment induced [001]‐preferred orientation growth in FAPbI3 films, and passivated defects within the crystal. The photodetectors based on PEAI‐AAE‐treated FAPbI3 film exhibits a fast response time of 485 µs/525 µs (rise time/fall time), high responsivity of 24.89 A W−1, and excellent specific detectivity of 1.56 × 1013 Jones. Moreover, the PEAI‐AAE‐treated FAPbI3 photodetector retained over 80% of its initial performance even after exposure to ambient air for over 720 h, demonstrating excellent long‐term stability. This study provides a green processing method that paves the way for future commercialization of perovskite‐based optoelectronic devices.