Fluorophenylalkylamine passivation ofα-FAPbI_(3)for highperformance and air-stable photodetectorsOA

Formamidinium-lead triiodide(FAPbI_(3))shows strong potential for high-performance photodetectors owing to its narrow band gap and superior thermal stability.However,fabrication of purephaseα-FAPbI_(3)via a simple method remains challenging.Herein,a facile strategy based on antisolvent engineering is introduced to obtain pure-phase FAPbI_(3)perovskite films by incorporating 3,5-difluorobenzylamine(DFBZ)into one-step antisolvent chlorobenzene.The findings reveal that the DFBZ molecule can effectively control the crystallization of perovskite and improveαphase stability of FAPbI_(3)perovskite.The perovskite films incorporating DFBZ exhibit a more uniform and denser surface morphology as well as prolonged carrier lifetime.The resulting photodetectors demonstrate a broad spectral response from 300 to 850 nm,with a responsivity of up to 0.49 A·W^(−1 )at 770 nm.The DFBZ molecule can effectively passivate perovskite crystal defects and also improve the stability of perovskite films.The optimized devices retain approximately 90%of their initial performance after storage in air environment of 25℃ and a relative humidity of 30%for 400 h.The strategy provides an effective route to prepare stable pure-phaseα-FAPbI_(3)perovskite films and broadband photodetectors.