High‐performance flexible perovskite photodetectors based on single‐crystal‐like two‐dimensional Ruddlesden–Popper thin films

Abstract Two‐dimensional Ruddlesden−Popper (2DRP) perovskites have attracted intense research interest for optoelectronic applications, due to their tunable optoelectronic properties and better environmental stability than their three‐dimensional counterparts. Furthermore, high‐performance photodetectors based on single‐crystal and polycrystalline thin‐films 2DRP perovskites have shown great potential for practical application. However, the complex growth process of single‐crystal membranes and uncontrollable phase distribution of polycrystalline films hinder the further development of 2DRP perovskites photodetectors. Herein, we report a series of high‐performance photodetectors based on single‐crystal‐like phase‐pure 2DRP perovskite films by designing a novel spacer source. Experimental and theoretical evidence demonstrates that phase‐pure films substantially suppress defect states and ion migration. These highly sensitive photodetectors show I_light/I_dark ratio exceeding 3 × 10⁴, responsivities exceeding 16 A/W, and detectivities exceeding 3 × 10¹³ Jones, which are higher at least by 1 order than those of traditional mixed‐phase thin‐films 2DRP devices (close to the reported single‐crystal devices). More importantly, this strategy can significantly enhance the operational stability of optoelectronic devices and pave the way to large‐area flexible productions.