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Solar panels operate most effectively under direct lighting conditions, limiting suitable installation locations within the built environment. Luminescent solar concentrators can concentrate diffuse light, offering a promising alternative in locations receiving minimal direct light. This allows the integration of LSCs in densely populated urban areas where sustainable energy is most needed. A basic LSC consists of a sheet of transparent host material embedded with luminophores. The luminophores absorb sunlight and reemit it at longer wavelengths. The emitted light is then trapped in the sheet through total internal reflection. Solar cells mounted at the waveguide edges convert the trapped light into electricity. In this work, commonly applied LSC materials PMMA and Lumogen F Red 305 were used to fabricate waveguides.

While most literature reports the use of cell casting for waveguide production, existing evidence indicates that this method can reduce the absorption properties of the organic dye, thereby decreasing the efficiency of the LSC. Injection molding presents a promising alternative; however, limited research is available on how this manufacturing process affects the optical properties of the used materials. To investigate this, a quantitative study has been conducted using a full factorial experimental design, in which both dye concentration and processing temperature were varied. Additionally, thinner samples were produced using compression molding to examine whether matched absorption levels, achieved by varying thickness and concentration, yield consistent optical behavior. The optical properties of all samples were characterized using UV-VIS spectroscopy.

Overall, the data suggest that higher processing temperatures generally increase the amount of light absorbed by the host material. This effect appears to be independent of the dye concentration, as samples containing the dye exhibit similar increases in absorption to those without it. Additionally, higher temperatures seem to increase the variation between repeated samples. Despite these findings, injection molding appears to be a viable method for fabricating waveguides, as these adverse effects are mitigated when operating within the recommended temperature range for PMMA. These results offer initial insights into how the injection molding process influences the optical properties of LSCs. This could unlock the significant design flexibility of this technique for LSC production and pave the way for new applications in the built environment.