Chloroplast-Inspired Carrier Circulation for Improved Photoelectrochemical Photodetectors Based on Ti₂CT Nanosheets

Here, a photoelectrochemical (PEC) photodetector with good flexibility and high photoresponsivity was successfully fabricated in a vertical structure, where the MXene (Ti₂CT) nanosheet and carbon black electrode were separated by adenosine triphosphate/nicotinamide adenine dinucleotide phosphate (ATP/NADPH)-incorporated solid-state electrolyte. The photocurrent and photoresponsivity can reach 1.84 μA/cm² and 8.89 μA/W, respectively, under a light intensity of 90 mW/cm² at a bias potential of 0.6 V, which are approximately 2.3 times those of Ti₂CT nanosheets. The addition of ATP and NADPH to the electrolyte also leads to a large decrease of the rise time from 0.76 to 0.26 s. Furthermore, the photodetector can continue to function and maintain stability under 45° bending and after 500 cycles of bending, indicating a robust device structure and great flexibility. The performance enhancement of the PEC photodetector can be attributed to the synergistic effect of electrolyte additives on Ti₂CT nanosheets, where ATP and NADPH greatly enhance the circulation and utilization of photogenerated carriers. This work suggests that the incorporation of chloroplast-inspired carrier circulation with two-dimensional nanosheets could achieve efficient light-current conversion, providing a new strategy to improve the performance of PEC-type photodetectors.