Solute-Engineered Functional Liquids Surpassing Deionized Water for High-Performance Liquid-Solid...

Liquid-solid (L-S) triboelectrification underpins emerging droplet-based triboelectric sensors (L-S TESs), which offer high sensitivity and rapid response; however, harnessing their full potential requires a nuanced understanding of how solute-solvent interactions at the liquid-solid interface govern charge transfer. This study systematically investigates the impact of distinct solute chemistries-encompassing strong hydrogen-bonding polyols (D-sorbitol, D-glucose, and D-sucrose) and ethers (diethyl ether (DEE) and tetrahydrofuran (THF)), on the triboelectrification of aqueous droplets at a PTFE interface. Crucially, we demonstrate that low-concentration DEE (0.1 wt%) increases the saturated transferred charge (Q_{SC - sat}) by approximately 30% relative to DI water under identical device and operating conditions. This enhancement is accompanied by favorable interfacial-tension modification and is proposed to arise from an increased availability of interfacial water for electron transfer. In contrast, high-concentration sucrose, a strong hydrogen-bonder, not only substantially impedes charge transfer but also uniquely induces a time-dependent charge decay. By correlating four key electrical output characteristics (including initial charge rate (R₀) and Q_{SC - sat}) with solution physicochemical properties, we elucidate the distinct roles of solute structure, concentration, and intermolecular forces. These findings clarify how solute chemistry and concentration influence charge accumulation in aqueous L-S TESs and provide a basis for tuning their electrical response through liquid composition.