Progress in Studies of Surface Nanotextures and Coatings with Nanomaterials on Glass for Anti-Dust Functionality

Abstract

Dust pollution presents a wide range of adverse effects to product functionalities and the quality of human life. For instance, when dust particles deposit on solar photovoltaic panels, sunlight absorption is significantly reduced, and solar-to-electrical energy conversion yield may be lowered by 51%- Conventional (manual) dust removal methods are costly, consume significant material resources, and cause irreparable damage to the solar glass surface. Therefore, it is critical to develop glass surfaces that can clean themselves or are easily cleaned by natural forces. Many approaches have been attempted to reduce dust deposition, such as developing superhydrophobic surfaces and preparing anti-static surfaces. This paper reviews the recent progress in studies of anti-dust and cleaning mechanisms or methodologies, which include investigation into micro- and nano-sized dust properties, dust deposition processes and adhesion mechanisms to surfaces, and the state-of-the-art approaches to anti-dust and easy-cleaning functions that tailor surface micro-/nanotextures, lowering surface energy via nanocoatings, and enhancing anti-static properties with nanomaterials. We compare the advantages and disadvantages of various approaches and discuss the research prospects. We envision that future research will be focused on developing transparent surfaces with multiple dust-proof functions to cope with dust-burdening operating environments.

Durability of Antireflective Sio2 Coatings with Closed Pore Structure

“…For AR Aero the closed pores prohibit water penetration, while we speculate that a low pore interconnectivity in AR Etch limits it sufficiently. This suggests that the open pore structure of AR Roll is more susceptible to water adsorption, which agrees with capillary forces dominating this process under high humidity conditions [13,35].…”

“…The hydrophilicity is rationalized for high energy silica surfaces [87] by an abundance of hydroxyl groups [88,89]. Other factors affect the wettability as well [35,90], one of which is surface roughness, which as it increases, should decrease the contact angle of an already hydrophilic surface, in accordance with Wenzel's model, suitable for such surfaces [91,92]. However, we observe larger contact angle for rougher surface, which we attribute to contaminants attained from shipping and storage of the commercial samples.…”

“…Consequently, efficient AR coatings are almost universally applied on solar glass, and the research focus has therefore shifted more towards durability and soiling mitigation [32]. The shift is well motivated considering that reports indicate insufficient durability for the desired 25 year lifetime [33] and annual losses due to soiling reach up to 50% in some cases [34,35]. Additionally, due to their sensitivity to scattering, losses associated with soiling have been shown to be considerably larger for concentrating techniques, like solar collectors, than for PV [36,37].…”

“…Porous silica coatings attain these properties either intrinsically [33,[55][56][57][58][59][60] or through additives or surface functionalization [24,30,48,49,[61][62][63][64][65][66][67]. Regardless, these coatings reduce dirt accumulation and associated transmittance losses [35] as well as the need for active cleaning [36]. Furthermore, if combined with tracking [68], nighttime flip [69] or dust screens [56], the effect of soiling is significantly reduced.…”