Enhancing Localized Evaporation through Separated Light Absorbing Centers and Scattering Centers

Abstract

This report investigates the enhancement of localized evaporation via separated light absorbing particles (plasmonic absorbers) and scattering particles (polystyrene nanoparticles). Evaporation has been considered as one of the most important phase-change processes in modern industries. To improve the efficiency of evaporation, one of the most feasible methods is to localize heat at the top water layer rather than heating the bulk water. In this work, the mixture of purely light absorptive plasmonic nanostructures such as gold nanoparticles and purely scattering particles (polystyrene nanoparticles) are employed to confine the incident light at the top of the solution and convert light to heat. Different concentrations of both the light absorbing centers and the light scattering centers were evaluated and the evaporation performance can be largely enhanced with the balance between absorbing centers and scattering centers. The findings in this study not only provide a new way to improve evaporation efficiency in plasmonic particle-based solution, but also shed lights on the design of new solar-driven localized evaporation systems.

Diameter effect of gold nanoparticles on photothermal conversion for solar steam generation

“…6,7,32 They also mixed Au NPs (light absorptive particles) and polystyrene NPs (scattering particles) to limit the incident light at the surface of the uids and generate heat. 33 A new alveolate structure with large area, small taper angle and varying nanogaps was also prepared to decrease plasmon propagation length. 34 Moreover, numerous nanostructures were designed and optimized to improve their photothermal efficiency, such as noble metals coated single-walled carbon nanotubes, 35 nanoparticles located on a solid substrate in solution, 16 plasmonic titanium nitride nanodisks, 36 GO/Au NPs composites, 37 etc.…”

Steam generation under one sun enabled by a floating structure with thermal concentration

“…[8][9][10][11][12] Plasmonic nanoparticles with absorption and scattering cross-sections exceeding their geometrical cross-sections have been recently developed and applied for direct solar steam generation [13][14][15][16][17][18][19][20][21][22][23][24] , but they typically require optical concentration of 10-1000x for steam generation. However, optical concentrators are expensive ($200/m 2 ) 25 , often accounting for a major portion of the capital cost of solar thermal systems.…”

Plasmonic nanostructures for advanced interfacial solarvapor generation

“…(b) 单纯吸收的金纳米颗粒, 和单纯散射的PSNP纳米颗粒. 该角色的分工, 能够比单一的 金纳米颗粒实现更强的吸收效果, 以及更高度的热学局域 [38] . (c) 2D衬底无尘纸的使用(左)能够比单纯的纳米金薄片(右)实现 更高的表面温度(ΔT~26°C)和较低的热传导耗散 [30] .…”

“…(b) Purely absorbing gold nanoparticles, and purely scattering PSNP nanoparticles. Division of responsibility enables enhanced absorptivity and localization effects [38]. (c) Airlaid paper, a 2D substrate, gives rise to higher surface temperature (ΔT~26°C) and lower heat conduction loss [30].…”