Temperature Dependence of Photoluminescence Spectra in Polystyrene

Abstract Our previous study of low-temperature photoluminescence (PL) in several common polymers revealed that PL intensity is, to different degree, temperature dependent in all of them. Even though polystyrene (PS) showed only moderate temperature dependence, it was the only studied polymer in which the wavelength, and therefore the energy, of the PL peak changed with temperature. In this work, we explored that effect in more detail and found that it is not present in all samples. Therefore, the effect is not intrinsic to PS, and we hypothesize that it is due to impurities. Moreover, our analysis revealed that the shift of the peak is due to a second PL peak, which displays a very strong temperature dependence. These PL results are also supplemented with UV-vis measurements on the same samples.