Temperature Dependences of the Hysteresis Optical Properties of CdS-LDPE Polymer Nanocomposites

Abstract

The article presents the results of an experimental study of the thermo-optical properties of a polymer composite nanomaterial based on 10 wt % CdS-LDPE. It is shown that the temperature dependences of the refractive index have a hysteresis in the heating-cooling cycle. The thermo-optical coefficients of the material during its heating and cooling, which had a negative value from –0.00026 to –0.0076 1/K were estimated. In the temperature range of 55–75°C, a strong nonlinearity of the temperature dependences of the refractive index of the width and energy gap of the material was observed. With increasing temperature up to 65°C, a decrease in the width of the forbidden zone was observed, and at temperatures above 65°C an increase in the width of the energy gap was observed. The maximum change in the band gap was about 0.2 eV. A strong change in the band gap in the temperature range 55–75°C is associated with a phase transition in the material. The detected thermo-optical properties of the polymer composite nanomaterial can be useful in the development of nanophotonic information-processing devices.