Investigation of polyvinyl butyral coatings with carbon quantum dots on the characteristics of silicon solar cells

Silicon solar cells with functional coatings based on polyvinyl butyral with carbon quantum dots. The change in the parameters of solar cells, when these coatings are used on the front surface of solar cells, is studied. A know-how method has been developed, which consists in the formation of a thin film of polyvinyl butyral with carbon quantum dots on the surface of solar cells. The coating is formed when the solution (isopropyl alcohol with polyvinyl butyral and carbon quantum dots) is pumped out of the cuvette in such a way that the contact boundary of the solution with the surface of the solar cell moves from top to bottom, while the process is carried out without and with ultrasound. Using an SFL MDR‑41 monochromator, the luminescence spectra of carbon quantum dots were obtained showing their strong fluorescence in the short-wavelength visible light region (350–450 nm). The coating thickness was measured by ellipsometry on a SE 800 instrument. Also, on the SolarLab 20-UST sunlight simulator, the main parameters of solar cells were measured before and after applying functional coatings. When applying functional coatings, the following pattern is observed: without exposure to ultrasound, an increase in efficiency is observed only at a concentration of carbon quantum dots in a solution equal to 119 ppm, and when exposed to ultrasound, a smooth increase in the efficiency of solar cells up to 2.34 % occurs at a maximum concentration of quantum dots of 463 ppm. In the short-wavelength region of light (365–470 nm), an increase in efficiency is observed for all concentrations of carbon quantum dots, which varies from 4.5 to 38 %. It is shown that functional coatings based on polyvinyl butyral with carbon quantum dots are promising and unparalleled coatings for solar cells, which also perform the additional function of a protective coating against ultraviolet radiation. This coating can also be used for other optoelectronic devices.