Recent developments in multifunctional coatings for solar panel applications: A review

Conventional resources of energy production by burning fossil fuels are detrimental to the earth's atmosphere leading to serious problems such as global warming and acid rain. As a result, renewable and green energy technologies have gained lot of attention in the recent years. In particular, the improvement of solar panel efficiency has grabbed a significant domain of researchers’ interest since sun is the year-round available source of energy that can be efficiently utilized for energy generation. However, a significant part of the incident solar energy is being lost due to the reflection at the air/glass interface as well as the accumulation of dusts on the modules. Hence, the surface morphology and characteristics of solar panel surfaces have recently been enhanced using multifunctional thin films or coatings in order to improve their self-cleaning, anti-reflection, anti-fogging and energy transmittance properties of the coated solar panels. A wide range of materials and methods have been employed in fabrication of solar panel coatings including superhydrophobic, superhydrophilic and photoactive coating surfaces. In this review, the current state of fabrication of solar panel coatings and their properties, including surface morphology, wettability, electrical conductivity and light transparency characteristics, are discussed. The review starts with discussing the fundamental concept of self-cleaning (i.e., superhydrophobicity/superhydrophilicity) and antireflective (i.e., transparency) properties followed by presenting a review of the recent methods and technologies used in manufacturing of superhydrophobic, superhydrophilic, photoactive and transparent thin films used in solar panel coatings. More importantly, the recent development on the fabrication and application of self-cleaning and dust-repellent antireflective coatings in solar modules have been discussed. Lastly, recent reports on advanced coatings with hybrid functionalities such as self-healing and antimicrobial activity are presented.