Quasi‐2D Ruddlesden–Popper Perovskites with Low Trap‐States for High Performance Flexible Self‐Powered Ultraviolet Photodetectors

Abstract Organic–inorganic perovskite photodetectors have drawn great attention due to their excellent performance and simple fabrication process. However, the detectivity of perovskite ultraviolet photodetectors (UV‐PDs) is comparatively poor because of the high defect density in chlorine‐containing 3D perovskites. Furthermore, 3D perovskites are easily degraded by high‐energy ultraviolet light, limiting their practical applications. Herein, high quality quasi‐2D Ruddlesden–Popper perovskite (Q‐2DRPP) (PMA)₂MA₂Pb₃Cl₁₀ (PMA⁺ = C₆H₅CH₂NH₃⁺, MA⁺ = CH₃NH₃⁺) films are prepared for UV‐PDs. It is found that Q‐2DRPP films have lower defect density and larger resistance than conventional 3D perovskite films, which improves the performance of UV‐PDs. The dark current density and maximum detectivity of the Q‐2DRPP film‐based device are 4.96 × 10⁻¹⁰ A cm⁻² and 2.59 × 10¹² Jones, respectively, which are both higher than those of the reference 3D perovskite‐based devices (2.29 × 10⁻⁸ A cm⁻² and 6.08 × 10¹¹ Jones). Moreover, Q‐2DRPP film‐based flexible UV‐PD has excellent bending stability; its photocurrent can retain 85% of its initial value after 1000 bending cycles. Q‐2DRPP film‐based devices have demonstrated long‐term light and environmental stability. These results imply that Q‐2DRPP films have great potential for high‐performance UV‐PDs.