Temperature Sensor Based on Colloidal Quantum Dots–PMMA Nanocomposite Waveguides

In this paper, integrated temperature sensors based on active nanocomposite planar waveguides are presented. The nanocomposites consist of cadmium selenide (CdSe) and cadmium telluride (CdTe) quantum dots (QDs) embedded in a polymethylmethacrylate (PMMA) matrix. When the samples are heated in a temperature range from 25 $^{\circ}{\rm C}$ to 50 $^{\circ}{\rm C}$ , the waveguided photoluminescence of QDs suffers from a strong intensity decrease, which is approximately quadratic dependent on temperature. Moreover, the wavelength peak of the waveguided emission spectrum of CdTe-PMMA shows a blue shift of 0.25 ${\rm nm}/^{\circ}{\rm C}$ , whereas it remains constant in the case of CdSe-PMMA. A temperature resolution of 0.1 $^{\circ}{\rm C}$ is obtained. QD waveguides have great potential for the development of photonic sensors because of their integration, multiplexing, and roll-to-roll fabrication capabilities.