Ultraviolet detection and imaging of one-dimensional cesium copper iodine single crystals synthesized by gradient crystallization

Abstract

The small size and large trap density have seriously hindered the application of cesium copper iodine single crystals (SCs). Herein, we propose a strategy for synthesizing high-quality and large-sized CsCu2I3 SCs by gradient crystallization. The as-synthesized CsCu2I3 SCs exhibit a large length of 1.7 cm with a low trap density of 4.17 × 109 cm−3. Moreover, such CsCu2I3 SCs show excellent photoelectric response to ultraviolet (UV) irradiation, owing to their high absorption coefficient, large Stokes shift, and one-dimensional electronic structure. The measured responsivity and detectivity of the CsCu2I3 SC-based photodetectors reach the maxima of 24.58 A/W and 1.02 × 1013 Jones, respectively, under 365 nm light irradiation. Due to the outstanding UV detection performance, such photodetectors are also utilized for achieving direct UV imaging with high resolutions.