High Performance Stretchable PVA-MoS2 Hydrogel Photodetectors with Electron–Cation Dual Charge Transport

Conventional ethylene glycol–borax cross-linked PVA-MoS 2 hydrogel photodetectors only rely on isolated MoS 2 electronic conduction pathways, which trigger severe nonradiative recombination of photogenerated electron–hole pairs and poor mechanical stretch resistance simultaneously. The lack of mobile ionic channels and unstable MoS 2 conductive networks severely limit both photoelectric conversion efficiency and long-term working stability under dynamic deformation. To break through these dual bottlenecks, herein we develop an ion-coordination strategy to construct a synergistic electron–cation dual transport system, where Li + forms reversible coordination bonds with oxygen-containing groups on the hydrogel matrix to simultaneously build two interconnected charge transport pathways. The cation migration channels offer free-moving Li + to neutralize photogenerated holes and weaken Coulomb confinement for suppressed carrier recombination, while the coordination anchors MoS 2 nanosheets firmly on polymer skeletons to maintain intact electronic percolation networks under stretching. We identify 4 mg mL –1 as the critical threshold concentration to form continuous long-range cation transport channels within the hydrogel network. Benefiting from the dual-channel synergistic effect, the optimized ion-modified hydrogel delivers a 364% elevated photocurrent density of 4.523 μA cm –2 at 0.6 V bias with 120 mW cm –2 illumination compared with unmodified pristine PVA-MoS 2 . Moreover, the dual-channel hydrogel maintains fully reversible and steady photoresponse under 200% tensile strain over 5000 s continuous illumination cycles. This facile coordination-mediated dual-channel engineering provides a universal strategy to synchronously optimize photoresponse and deformation tolerance, shedding new light on high-performance, long-lifetime stretchable wearable photodetectors.