Enhanced Perovskite Film Quality and Hole Transport through V₂CT_<i>x</i> MXene Modulation for Self-Powered CsPbCl₃ UV Photodetectors

Enhancement of the perovskite film quality and charge transfer capability is crucial for enhancing device performance. The all-inorganic CsPbCl₃ perovskite, which shows great potential as an absorber layer in ultraviolet photodetectors (UV PDs), has been hindered by poor material stability and high interface states, limiting its widespread application. In this work, the quality of the CsPbCl₃ films and the perovskite/Au electrode interface were synergistically modulated using V₂CT_<i>x</i> MXene. After additive (CsPbCl₃@V₂CT_<i>x</i>) and interface (CsPbCl₃/V₂CT_<i>x</i>) engineering, the optimal properties of CsPbCl₃ films and the van der Waals (vdW) bonding of V₂CT_<i>x</i> strengthen the charge extraction and hole transport while reducing nonradiative charge recombination caused by internal defects and interface states. Ultimately, the UV PD featuring the FTO/SnO₂/CsPbCl₃@V₂CT_<i>x</i>/V₂CT_<i>x</i>/Au structure manifests outstanding performance under the self-powered mode, attaining an extremely high responsivity of up to 1.01 × 10³ mA/W and a considerable specific detectivity of 5.46 × 10¹¹ cm Hz^1/2/W (365 nm, 0.16 mW/cm²) coupled with a swift rise/decay time of 1.54/1.50 μs. Even after 30 days under an air atmosphere, the responsivity of the device remains at 8.46 × 10² mA/W, indicating extraordinary stability. This approach offers a novel way to enhance the performance of UV PD based on the CsPbCl₃ perovskite through the dual strategy of V₂CT_<i>x</i> MXene modulation.