Scalable, Low-Cost Fabrication of Selective Solar Absorber by Ultrasonic Spray Coating

Ye Seul Kwon1

Yang Li1,Email

Baoling Huang1,Email

Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China

Abstract

Current fabrication methods of selective solar absorbers (SSAs) involve high cost and extensive processing steps. To push further commercialization of SSAs, utilization of economically scalable methods is preferable. Here we demonstrate the fabrication of large-area high-performance all-ceramic plasmonic SSA using ultrasonic spray coating (USC) under ambient conditions, which comprises a solar absorbing layer of titanium nitride nanoparticles and a silicon dioxide anti-reflection layer. The coatings are optimized by monitoring their optical spectra and surface morphology, and the key parameters in fabricating high-performance SSAs by USC are identified and explored, including the substrate surface energy, solution concentration, and deposition flow rate. The fabricated large-area SSA shows a high solar absorptance of 90% and ultralow infrared emittance of 2%, resulting in solar-thermal conversion efficiency of 89%. This performance is comparable to those of best commercial SSAs (87%–91%). The solution-based fabrication significantly reduces the laboratory-scale cost of our SSAs down to about 30% the price of commercial products. The low cost and high performance as well as excellent thermal stability of the solution-processed SSAs render them attractive for large-scale solar thermal applications.

Scalable, Low-Cost Fabrication of Selective Solar Absorber by Ultrasonic Spray Coating