Stretchable and self-healing photoelectrochemical photodetectors based on Ti2CTx nanosheets hydrogels

•Synthetic optoelectronic hydrogels using MXene and PVA for further construction of hydrogel photodetectors.•Under the PEC measurement system, the hydrogel photodetector achieves a responsivity of 2.96 μA W−1.•The hydrogel photodetector maintains stable performance after 1500 cycles of stretching.•The hydrogel photodetector remains stable performance after 50 cycles of self-repair. Hydrogels are excellent stretchable engineering materials composed of polymers, which are widely studied as flexible conductors in smart, flexible devices. However, hydrogels have only been studied for their electrical conductivity, which hinders their further application in optoelectronic devices. Herein, a hydrogel photoelectrochemical (PEC) photodetector by using polyvinyl alcohol (PVA) hydrogel as an electrolyte carrier and further embedding Ti2CTx nanosheets in the hydrogel is presented. Under a bias potential of 0.6 V and a light intensity of 60 mV cm−2, the photodetector exhibited a photocurrent density of 0.178 μA cm−2 and a responsivity of 2.96 μA W−1. Furthermore, due to the structure of the special nanosheets network of hydrogel photodetectors, the photodetector maintained stable properties even after 1500 cycles of stretching at 100% strain and 50 cycles of cutting-off the self-healing cycle, this indicates that the prepared hydrogel photodetector is a high-quality stretchable, self-healing device. This study provides a novel approach for hydrogel functionalization and widens the design horizons and potential applications of photodetectors. [Display omitted]