Executive Summary : | "PV system production capacity has increased dramatically over the years around the world. The accumulation of dust and grime on the top surface of PV systems, however, results in a significant reduction of energy yield. The solar energy incident on the top cover is reflected, scattered, and sometime absorbed by dust and dirt particles, resulting in inadequate solar radiation reaching the surface of solar cells, limiting their performance. The optical transmission loss of solar glass covers on PV panels can be as high as 70% in arid and low-rainfall areas, resulting in a net loss of PV power output of approximately 26–40%. As a consequence, efforts are being undertaken to increase the energy yield of solar PV systems with extended lifespans and low-cost designs.
To address soiling losses in PV systems, on the front sheet (glass cover) is often coated with self-cleaning coatings to increase efficiency and maintain the energy yield. In the arid/semi-arid region, where water shortage is a major issue, waterless automated cleaning procedures like robotic cleaning and other innovative dry cleaning are proving to be effective cleaning methods. Mazumder et al. presented a transparent self-cleaning dust shield based on the Electrodynamic Screen (EDS) technology, which uses an electrostatic repulsion mechanism to operate as a dust curtain under the effect of high voltage (greater than threshold value) generated by solar panels. However, it is to be noted that fabrication of EDS for solar glass covers requires sophisticated equipment for the deposition of electrode patterns based on TCOs, thereby restricting their use for low-cost applications. The ability to deposit coatings by low-cost approaches such as inkjet printing, spray pyrolysis, etc., has aroused much interest in solution processible materials for various applications. The present approach focuses on the development of large-area, cost-effective ZnO based TCOs by solution combustion synthesis. Solution combustion synthesis has lately been explored as a strategy to overcome problem of creating large-area TCO thin films by cost-effective approaches. It is critical to provide an appropriate protective layer on the EDS front sheets to ensure transparency for incoming light, electrical insulation, and moisture barrier. As a result, in recent years, a greater focus has been given on front-sheet materials with specific functional features, such as anti-reflective, anti-soiling, and abrasion-resistant protective coatings. The characteristics of such functional materials, along with their predicted lifespan, interactions with other module components, and compatibility with diverse climates, are all of great interest. Therefore, development of suitable large-area, high-rate deposition techniques is required for large-scale use, particularly in PVs as well as various advanced glazing (windows)." |