A Multifunctional MWCNTs‐Reinforced Chitosan–Gelatin Conducting Hydrogel for Triboelectric Nanogenerator and Artificial Opto‐Electronic Synapse Applications

Hydrogel systems uniting electrical conductivity, sensory responsiveness, and mechanical integrity are emerging as foundational building blocks for next‐generation bioinspired electronics. Triboelectric nanogenerators (TENGs) represent a particularly attractive avenue for recovering ambient mechanical energy, while optoelectronic neuromorphic synapses offer energy‐efficient, in‐sensor optical processing reminiscent of biological visual pathways. In this work, a chitosan–gelatin (CSG) conducting hydrogel is prepared via solution casting and reinforced with carboxyl‐functionalized MWCNTs and NaCl. The functionalized nanotube network establishes strong interfacial interactions within the biopolymer matrix, yielding a material with controlled swelling behavior, adequate mechanical resilience with favorable viscoelastic characteristics. The concurrent ionic–electronic transport pathways and elevated charge mobility underpin a well‐defined structure–property relationship, translating directly into efficient mechanical‐to‐electrical energy conversion. The fabricated TENG achieves an open‐circuit voltage of ∼398 V, short‐circuit current of ∼96 µA, and power density of ∼132.91 µW/cm 2 , maintaining stable output over 10,000 mechanical cycles. The same hydrogel, configured as a two‐terminal optoelectronic device, reproduces key synaptic behaviors including short‐to‐long‐term memory transition (STM‐LTM) and paired‐pulse facilitation (PPF) of ∼120% under optical stimulation. Collectively, this bio‐derived hydrogel platform bridges triboelectric energy harvesting and neuromorphic optoelectronic sensing within a unified material system, charting a viable course toward self‐powered, brain‐inspired sensory electronics.