Spectrum Selective Interfaces and Materials toward Nonphotothermal Saltwater Evaporation: Demonstration with a White Ceramic Wick

Most solar desalination efforts are photothermal: they
evaporate
water with “black” materials that absorb as much sunlight
as possible. Such “brine-boiling” methods are limited
by the high thermal mass of water, i.e., its capacity to store and
release heat. Here, we study the light-enhanced evaporation by a hard,
white, aluminum nitride wick, and propose a route to selectively target
salt-water bonds instead of bulk heating via deep-UV interactions.
Through experiments and analyses that isolate the effects of light
absorption and heating in aluminum nitride, we provide experimental
evidence of a light-driven, spectrum-selective path to nonphotothermal
saltwater evaporation. Leverage of these light-matter interactions
in white ceramic wicks may achieve low-cost, low-energy desalination,
reduce the heat island effects of traditional solar technologies,
and contribute to future cooling technologies where drought is also
a concern.