Non-centrosymmetric phase of [C4N2H14][CdBr4] for solar-blind ultraviolet detection

Abstract

Two-dimensional (2D) organic–inorganic halide perovskites (OIHPs) have attracted extensive attention due to their solution processability, structural diversity and tuneable optoelectronic properties. However, there are very few reports on wide-bandgap OIHPs for ultraviolet (UV) detection. Herein, a novel layered wide-bandgap OIHP, [C₄N₂H₁₄][CdBr₄], was synthesized by a facile hydrothermal method. The non-centrosymmetric structure of [C₄N₂H₁₄][CdBr₄] was solved by single-crystal X-ray diffraction (XRD) and the second harmonic generation (SHG) test. This compound exhibits a wide optical bandgap (E_g) of approximately 3.88 eV and a long carrier lifetime of about 641 μs. Compared to the reported centrosymmetric phase of [C₄N₂H₁₄][CdBr₄], our sample achieved a superior responsivity of 32.19 uA W⁻¹ under 254 nm illumination with a fast response speed of τ_r = 283 μs. This work provides a promising strategy for designing and manufacturing new layered OIHPs as candidate materials for solar-blind UV detection.