A Solar Thermoelectric Nanofluidic Device for Solar Thermal Energy Harvesting

Harvesting the low-grade (<100 degrees C) solar thermal energy with ionic heat-to-electricity conversion shows great promise but low efficiencies due to the challenges encountered in regulating ionic thermophoretic mobilities. Here, we used nanochannels to regulate thermal-driven ion transport properties and described a solar thermoelectric nanofluidic device (STEND). The localized heat generated by the broad-band plasmonic absorption of the gold nanostructure is focused at the orifice of the nanochannel, which builds up a large temperature gradient inside the nanochannel. The following thermal-driven ionic charge separation was enhanced by the ion-selective nanochannel, resulting in large thermal membrane potential (TMP). The Seebeck coefficient and the TMP reached 0.76 mV/K and 23 mV, respectively, in an aqueous KCl solution. The performance of the device was improved further by the enhancement of electrostatic interaction between the ions and the nanochannnels, the increase of the membrane thermal resistance, and the decoupling of the ion concentration polarization (ICP) regions. This study supports the understanding of thermal-driven ion transport at nanoscale and provides a new strategy for harvesting solar thermal energy. [GRAPHICS] .

Automated summary

This study utilized nanochannels to regulate thermal-driven ion transport properties and proposed a solar thermoelectric nanofluidic device (STEND). By enhancing ion-selective nanochannels, the device performance was improved, offering a new strategy for harvesting solar thermal energy.