CuO\nNanobelt Array-Based\nOmnidirectional UV–Visible–NIR\nPhotoelectrochemical Photodetectors

Photoelectrochemical\nphotodetectors (PEC PDs) are promising\nin\nunderwater optoelectronic devices because of their low cost, good\nsensitivity, and self-powered characteristics. However, achieving\nhigh-performance omnidirectional visible PEC PDs using seawater as\nthe electrolyte is still challenging, hindering their practical application.\nThis work successfully synthesized CuO nanobelt arrays (NAs) on a\nlinear copper wire via a low-temperature solution method with an annealing\nprocess. The self-powered CuO NA PEC PDs exhibit good UV–vis–NIR\nphotoresponse ranging from 365 to 850 nm with a high responsivity\nof −83.18 mA/W (455 nm irradiation), a fast response time of\n28/140 ms, and good stability in simulated seawater. The high responsivity\nsurpasses all of the reported PEC PDs when seawater or simulated seawater\nis used as the electrolyte. In addition, the CuO NA PEC PDs show good\n360° omnidirectional photodetection and underwater wireless optical\ncommunication capabilities. This work provides new insights into achieving\nomnidirectional visible PEC PDs and demonstrates the potential application\nof CuO NAs in underwater optoelectronic devices.