Abstract
Daylighting structures,including solar cells and building windows,utilize sunlight whilst suffering from undesired solar heat and outdoor dust contamination.A radiative cooling system that is transparent to sunlight and has a superhydrophobicsurface would cool and clean the daylighting structures in a sus-tainable manner.However,the majority of the current daytime radiative cooling systems were designed to fully reflect the incident sunlight to maximize the cooling power.In this work,we optimized both the sunlight transmission and infrared thermal irradiation by modeling the size-dependent scattering and ab-sorption of light by SiO2 spheres embedded in a polymer matrix,we found that the use of nanospheres(20 nm) enabled both high sunlight transmittance (＞ 90％) and infrared emissivity (～0.85).This theo-retical prediction was confirmed by experimental measurements of a solution-processed nanocomposite film.When coated on a solar cell,the as-prepared film not only preserved the power conversion effi-ciency of the cell (14.71％,uncoated cell has an efficiency of 14.79％) but also radiatively cooled the cell by up to 5 ℃ under direct sunlight.This reduction of the operating temperature of the solar cell further enhanced its electrical power output,evidenced by an increase in the equilibrium temperature of the LED load by about 14 ℃.The nanoscale textured surface formed by the nanospheres further led to su-perhydrophobicity and thus excellent self-cleaning performance (efficient removal of dust by wind and/or water droplets).
基金项目
National Natural Science Foundation of China(52071114)
National Natural Science Foundation of China(52001100)
Aviation Science Foundation of China(20163877014)
NETL
NSTL
维普
万方数据