Optical effects of water droplets on the performance of solar cell covered with a hydrophobic thin layer

Abstract

Due to the challenges of environmental protection and the exhaution of traditional energy carriers, electricity produced by solar cells is increasingly coming to the fore. The efficiency of solar cells is significantly influenced by many factors, including the purity of the solar cell. The application of self-cleaning coatings is a novel solution for cleaning. In addition, in case of using water to remove dirt and to cool the solar cell, a drop of water falling on nanotechnology thin layers also affects the radiation reaching the surface of the solar cell. The present study focuses on the latter effect. When a water drop appears, on the one hand, the illumination of the solar cell surface becomes uneven, and on the other hand, the water drop redirects some of the otherwise reflected rays back to the surface of the solar cell, so it has an anti reflective effect, we are investigating these two phenomena. The quantitative findings and conclusions were formulated on the basis of the data generated using the C++ model created in the RayTracer framework program. In addition to the equations describing light refraction and light reflection, the model uses also the Fresnel equations for determine the intensity of the light beam for drops of different shapes, different locations, and different coverage ratios. It also examines the dependence on the spectral components of sunlight and the differences resulting from different angles of incidence. The results obtained with the help of the model are also supported by measurement data on the performance conditions of a solar cell covered with water droplets. In addition, by examining the intensity relationships of solar radiation reaching the surface of water covered solar cells, the results can also be used to examine the optical and energetic effects of water droplets on plant leaves or human skin.