Optical nonlinearity of coumarin-CdTe@PMMA nanohybrid films for smart temperature sensing in luminescent solar concentrator windows

This study presents coumarin-CdTe@PMMA nanohybrid films as dual-function materials luminescent solar concentrator (LSC) windows, enabling simultaneous energy harvesting and autonomous temperature sensing. X-ray diffraction (XRD) characterization confirmed the amorphous nature of all the films and revealed the influence of CdTe quantum dots (QDs) on enhancing light absorption and emission efficiency through quantum confinement effects. Optimized films at 0.8 wt% CdTe QDs concentration demonstrated remarkable emission properties, optical nonlinearity and effective photon trapping efficiency of 76.32%. Differential scanning calorimetry (DSC) revealed significant improvements in thermal stability, with the glass transition temperature increasing from 95 °C to 135 °C as CdTe QDs concentration increased to 1 wt% doping concentration. Reversible temperature-dependent fluorescence quenching validated the suitability for the optimized sample as emission-dependent and power-dependent LSC temperature sensors. The thermometric response parameters demonstrated strong linear dependence with the highest precision evidenced by the average relative temperature sensitivity values of 0.238% for emission-dependent and 0.923% for power-dependent LSC temperature sensors. These results highlight the potential of coumarin-CdTe@PMMA nanohybrids for multifunctional applications, such as smart LSC windows capable of combining renewable energy generation with synchronized temperature monitoring, advancing the development of sustainable and intelligent building technologies. This application aligns with sustainable development goals (SDGs), specifically SDG 7 (Affordable and Clean Energy) and SDG 9 (Industry, Innovation, and Infrastructure).