Plasmonic Resonance Enabling 2D Perovskite Single Crystal to Detect Telecommunication Light

Abstract High performance photodetectors (PDs) based on two‐dimensional (2D) perovskite single crystals (SCs) have been demonstrated with improved stability with respect to those based on their three‐dimensional counterparts. However, due to their large energy band gaps, response of 2D perovskite PDs is limited in the ultraviolet and visible range. In this study, a broadband PD based on (PEA)₂PbI₄ (PEA = C₆H₅(CH₂)₂NH³⁺) 2D perovskite SC is demonstrated by incorporating thermally annealed Au nanoparticles (NPs). Introduction of Au NPs brings forward enhancement in photocurrent over a broadband wavelength range with the dark current being maintained. In the light absorption range of (PEA)₂PbI₄, photocurrent enhancement is owing to the enhanced localized electric field induced by Au NPs. Beyond the (PEA)₂PbI₄ absorption range of 650–900 nm, the photocurrent enhancement factors reach 1000% in average, which arises from the hot holes produced by Au NPs. It is also emphasized that the response wavelength of the PD has been extended to the telecommunication band; specifically, the light signals at 1310 nm can be converted to stable on‐off electric signals by the plasmonic PD. This work promotes the development of broadband, sensitive solution‐processed perovskite PDs, providing a promising strategy for realizing photodetection in the telecommunication range.