Hot-cold design supercharges solar thermoelectric efficiency by 15x

Researchers at the University of Rochester have developed a novel "hot-cold" design that increases the efficiency of solar thermoelectric generators (STEGs) by 15 times, potentially bridging the gap between STEGs and conventional photovoltaic solar panels. Unlike traditional solar panels that rely on photovoltaic cells, STEGs generate electricity by exploiting the temperature difference between a hot side and a cold side through the Seebeck effect. Historically, STEGs have been limited by low efficiency, converting less than 1% of sunlight into electricity compared to about 20% for residential solar panels. The new approach improves efficiency not by altering semiconductor materials but by enhancing thermal management on both the hot and cold sides of the device. The innovations include using femtosecond laser pulses to etch nanoscale structures into tungsten on the hot side, creating a "black metal" surface that selectively absorbs solar wavelengths while minimizing heat loss. This surface is covered with a plastic layer that traps heat by limiting convection and conduction, effectively raising