Harnessing ultralow friction in monolayer MoSe2 for high-efficiency direct-current generation

Strong Au-MoSe 2 electrostatic coupling suppresses dynamic wrinkling, achieving ultralow friction with a coefficient of 0.009. • The MoSe 2 /Au sliding Schottky junction enables near zero wear over 5000 cycles and a DC density of 1.13 × 10 6 A/cm 2 . • Ultralow friction minimizes energy dissipation, maximizing nonequilibrium carrier excitation and energy conversion efficiency. High-output tribovoltaic nanogenerators (TVNGs) suffer from severe interfacial wear and energy dissipation under high contact pressures, critically limiting their conversion efficiency and lifespan. Here, we overcome this challenge, by designing a TVNG based on a Pt/monolayer MoSe 2 /Au Schottky junction, which achieves simultaneously ultra-low friction, high wear resistance, and remarkable current density. Micro/nanoscale experiments and density functional theory (DFT) calculations reveal that strong electrostatic coupling, which is induced by cross-interfacial charge transfer between the Au substrate and MoSe 2 , effectively suppresses out-of-plane wrinkling, yielding an exceptionally low friction coefficient of 0.009. Under reciprocating sliding with a diamond probe (∼1.39 GPa contact stress), the device maintains near “zero-wear” structural integrity and delivers a remarkable direct-current density of 1.13 × 10 6 A/cm 2 without perceptible degradation over 5000 cycles. Mechanistically, the robust MoSe 2 -Au interaction provides high interfacial adhesion energy, preventing mechanical energy from dissipating into localized deformation. Crucially, this ultra-low friction effectively suppresses phononic friction dissipation, which drives the efficient excitation of non-equilibrium carriers and substantially enhances the overall energy conversion efficiency. Concurrently, the stable, atomically flat Schottky contact ensures efficient carrier separation, providing a robust theoretical foundation for designing durable, high-power self-powered micro/nano-devices. Download: Download high-res image (183KB) Download: Download full-size image