Solar energy harvesting devices likephotovoltaic panels are facing a major issue with the settlement of dust ontheir surfaces which in turn degrade their personal performances. Dust particlescontain alkaline and alkaline earth metals and some of them yield a chemically active liquid solution. These liquidsolutions after interacting with solid surfaces of Solar Panels form hydroxylsand with Micro or Nano size of cavities on surfaces. These happenings lower theoptical properties of solar panel surface and lower the solar radiationconcentration at irradiated surfaces. The driedliquid solution in between dust particles and solid surfaces increaseadhesion of dust particles and as a result,the cost of removing dust particles is also reaching new margins.One of the best remedy to eradicate theseproblems is implementing self-cleaning techniques just like we observe in thecases of Lotus leaves, Rice leaves, Red Rose petals and Fish Scales. Surface Hydrophobicity can be bestimplemented here to resolve the problem. Low surface energy and surface texturewill generate hydrophobic characteristics at the surface.
Various methods have been proposed to generate hydrophobiccharacteristics at the surface. Some ofthem are Phase separation and electrochemical deposition, Sol-Gel processing, Electrospinning, Laser Texturing, SolutionImmersion and Plasma treatment (Dar, et al., 2015).
Among them, Surfacetexturing has many problems in its real-timeapplications. Silicon Oil Impregnation is more viable to improve the opticaltransmittance of the hydrophobized surfaces. But, with its implementation, OilImpregnation cloaks the dust particles and reduces Optical transmittance. So,endeavors towards improving Outdoor tests are still in progress.Applications of Hydrophobicityin Energy Harvesting Devices: -Hydrophobic surfaces find a vast number of applications in Solar EnergyHarvesting Devices when the surface is exposed to open environment. Inorder to enhance the device performance, dust particles on surfaces should beremoved effectively. Devices like Photovoltaic panels, Heliostat, Troughs,Selected surfaces for thermal applications and solar receivers can beconsidered for these category applications.
Challenges of Hydrophobizationof Transparent Substrates: -Solvent-Induced crystallization is one of theeconomically viable practices for hydrophobizingthe polycarbonate surface. Time factor and temperature of crystallization aretwo major aspects of balancing surface texture (Buin, et al., 2015). Here, thecrystallized surface’s contact angle with water droplets is the key factortowards analyzing the self-cleaning action of solar devices. Strong adhesion ofliquid droplets on the crystallized surfacewill create many bottlenecks to deal with.Opportunities forFuture: -Surface Hydrophobicity is the most sought-after technique regarding theimprovement of functionality of solar energy harvesting devices.
In order toachieve the desired result, self-cleaning of active devices is mandatory. Onceit is achieved, it will be a major breakthrough in enhancing the performancesof solar harvesting devices.Closing Remarks: -Self-cleaning of solar energy harvestingdevice surfaces becomes a challenging task in desert areas where the majorpower needs usually met through solar needs. The chances of enhancing thehydrophobicity of surfaces with high optical transmittance will decide the cost-effectiveself-cleaning mechanisms for solar energy harvesting devices.