Nanofluidic\nThermoelectric Transducer with Ultrahigh\nand Tunable Sensitivity

Thermosensitive transient receptor potential (thermoTRP)\nion channels\ncan transduce external thermal stimuli to neural electrical signals,\nallowing organisms to detect and respond to changes in environmental\ntemperature. Reproducing such ionic machinery holds promise for advancing\nthe design of highly efficient low-grade thermal energy harvesters\nand ultrasensitive thermal sensors. However, there still exist challenges\nfor artificial nanofluidic architectures to achieve comparable thermoelectric\nperformance. Here, we report nanofluidic thermoelectric transducers\nwith ultrahigh and tunable sensitivities controlled by electrostatic\ngating in graphene nanochannels. The equivalent Seebeck coefficient\ncan be significantly boosted and reaches 1 order of magnitude higher\nthan the current state of the art, even beyond thermoTRP ion channels.\nThe improvement is attributed to substantial slippage on the highly\ncharged graphene surface, leading to enhanced electrokinetic ion transport\ninside the graphene channel, which is confirmed by a scaling theory\nfor thermoelectric coupling as well as molecular dynamic simulations.\nThe dependence of the nanofluidic thermoelectric on the concentration,\nchannel size, and cation types is also investigated to further clarify\nthe underlying mechanism.