2D Perovskite Sr₂ Nb₃ O₁₀ for High-Performance UV Photodetectors

2D perovskites, due to their unique properties and reduced dimension, are promising candidates for future optoelectronic devices. However, the development of stable and nontoxic 2D wide-bandgap perovskites remains a challenge. 2D all-inorganic perovskite Sr₂ Nb₃ O₁₀ (SNO) nanosheets with thicknesses down to 1.8 nm are synthesized by liquid exfoliation, and for the first time, UV photodetectors (PDs) based on individual few-layer SNO sheets are investigated. The SNO sheet-based PDs exhibit excellent UV detecting performance (narrowband responsivity = 1214 A W^-1 , external quantum efficiency = 5.6 × 10⁵ %, detectivity = 1.4 × 10¹⁴ Jones @270 nm, 1 V bias), and fast response speed (t_rise ≈ 0.4 ms, t_decay ≈ 40 ms), outperforming most reported individual 2D sheet-based UV PDs. Furthermore, the carrier transport properties of SNO and the performance of SNO-based phototransistors are successfully controlled by gate voltage. More intriguingly, the photodetecting performance and carrier transport properties of SNO sheets are dependent on their thickness. In addition, flexible and transparent PDs with high mechanical stability are easily fabricated based on SNO nanosheet film. This work sheds light on the development of high-performance optoelectronics based on low-dimensional wide-bandgap perovskites in the future.