Study of the Scattering Effect by SiO₂ Nanoparticles, in a Luminescent Solar Concentrator Sensitized with Carbon Dots

Luminescent solar concentrators (LSCs) have become an attractive way to produce green energy via their integration into buildings as photovoltaic windows. Recently, carbon quantum dots (C-QDs) have become the most studied luminescent material for the manufacture of luminescent solar concentrators due to their advantages, such as low toxicity, sustainability, and low cost. Despite the advantages of carbon quantum dots, they remain a low-efficiency material, and it is difficult to fabricate LSCs with a good performance. To address this problem, some of the research has used SiO₂ nanoparticles (Nps) to produce a light-scattering effect that helps to improve the system performance. However, these studies are limited and have not been discussed in detail. In this regard, this research work was designed to evaluate the contribution of the scattering effect in different systems of carbon quantum dots used in a possible luminescent solar concentrator. To carry out this study, C-QDs and SiO₂ Nps were synthesized by hydrothermal methods and the Stober method, respectively. We used different concentrations of both materials to fabricate film LSCs (10 × 10 cm²). The results show that the light scattered by the SiO₂ Nps has a double contribution, in terms of light redirected towards the edges of the window and as a secondary source of excitation for the C-QDs; thus, an improvement in the performance of the LSC is achieved. The best improvement in photoluminescence is achieved when the films are composed of 20% wt carbon quantum dots and 10% wt SiO₂ Nps, reaching a gain of 16% of the intensity of the light incident on the edges of the window with respect to the LSCs where only C-QDs were used.