Highly Stable and Stretchable Ti ₂ CT _<i>x</i> /rGO Hydrogel and Its Application in Photodetectors with Enhanced Performance

Two-dimensional transition metal carbides (MXene) show great promise for use in flexible optoelectronics, but they are prone to rapid oxidation and nanosheet restacking, which can degrade the device performance and longevity. In this study, we address this issue by creating a dual-network conductive hydrogel made up of Ti2CTx MXene and reduced graphene oxide (rGO). The rGO nanosheets act as conductive spacers, preventing the restacking and oxidation of the Ti2CTx nanosheets while enabling charge transport. The resulting Ti2CTx/rGO composite hydrogel achieves an impressive photocurrent density of 0.375 μA cm–2 under a 0.4 V bias and 120 mW cm–2 of illumination. This is 68.2% higher than that of a pure MXene hydrogel (0.223 μA cm–2). Furthermore, the composite demonstrates outstanding mechanical and environmental stability. It retains 79.2% of its photocurrent under 200% tensile strain compared to 53.8% for the pure MXene system and exhibits only a 40% decrease in photocurrent after 15 days, significantly outperforming the 70% decay observed in the control device. This work provides an effective strategy for developing stable, high-performance MXene-based hydrogels for advanced, wearable, optoelectronic applications.