In-Situ High-Performance Photodetectors Based on CdSe Nanobelts Decorated with CuI Nanocrystals

Photodetectors with high responsivity are crucial elements in various modern industrial applications. CdSe nanobelts, due to their direct bandgap, have emerged as a high-performance material with wide-ranging applications in photodetector technology. For CdSe nanobelt-based photodetectors, which already exhibit broad applicability, enhancing their performance is a key area of ongoing research and development. In this study, we report the successful synthesis of CdSe nanobelt photodetectors decorated with CuI nanocrystals through a combination of physical vapor deposition and a poly(vinyl alcohol) film transfer process. This approach significantly improves the performance of the photodetectors. In the 405–765 nm range with fixed light intensity, the responsivity and external quantum efficiency of the CuI@CdSe photodetectors peaked at 242.88 A/W and 579.18%, 11.6 times higher than those of the in-situ CdSe photodetectors. At 520 nm with 0.94 mW/cm² intensity, these metrics reached 289.53 A/W and 860.727%, about 38.645 times higher than those of the in-situ CdSe photodetectors. To further demonstrate the enhanced performance, we prepared an image signal transmission system to validate the optical imaging capabilities of the photodetectors. The CuI@CdSe photodetectors successfully converted a preset image into the final output image with a resolution of 110 × 93 pixels, showcasing their potential for practical imaging applications. This work significantly boosts the responsivity and external quantum efficiency of CdSe photodetectors through the incorporation of CuI nanocrystals. It also paves the way toward creating advanced high-performance photodetectors of the future.