Recent progress on transparent and self-cleaning surfaces by superhydrophobic coatings deposition to optimize the cleaning process of solar panels

Superhydrophobic transparent coatings have recently gained significant attention in the solar energy field due to their ease of preparation, low cost, self-cleaning process, and high effectiveness in reducing dust adhesion to the surface. However, very few journals have addressed the application of self-cleaning coatings for the solar energy field due to its complexity. The transparency and the roughness responsible for the self-cleaning feature are two contradictory parameters; Increasing one parameter strongly implies a decrease in the other, Moreover, the durability of the coatings is also considered as an essential parameter for their industrial-scale acceptance, as solar panels are exposed to highly aggressive environments. Therefore, studying superhydrophobic coatings oriented for solar applications can be challenging. Most reviews reported in the literature provided limited information on the choice of materials, deposition techniques, and synthesis protocols of transparent and superhydrophobic coatings. Several reviews have addressed the topic of superhydrophobic coatings, which have various applications such as water/oil separation, anti-ice, anti-biofouling, self-cleaning and more. However, there are not many reviews that specifically focus on the development of superhydrophobic coatings for solar applications. This is mainly due to the transparency constraint required for the solar applications, making this topic particularly challenging. In the past five years, only five reviews have been published on this subject. In this review, we discuss in detail the impact of solar panel dust accumulation and its impact on their efficiency. Then, we discuss the principle of superhydrophobicity and self-cleaning as well as the principle of transparent coatings. In this review, we aim to address this gap in knowledge by discussing in detail the impact of dust accumulation on solar panel efficiency, as well as the principles of superhydrophobicity, self-cleaning, and transparent coatings.