Tunable White-Light Emission from Conjugated Polymer-Di-Ureasil Materials

Conjugated polymer (CP)-di-ureasil composite materials displaying a tunable emission color from blue to yellow through white have been prepared using a simple sol-gel processing method. The tunability of the emission color arises from a combination of energy transfer between the di-ureasil and the CP dopant and the excitation wavelength dependence of the di-ureasil emission. Incorporation of the CP does not adversely affect the bulk or local structure of the di-ureasil, enabling retention of the structural and mechanical properties of the host. Furthermore, CP-di-ureasils display superior thermal and photostability compared to the parent CPs. Thermogravimetric analysis shows that the onset of thermal decomposition can be increased by up to 130 degrees C for CP-di-ureasils, while photostability studies reveal a significant decrease in the extent of photodegradation. Steady-state photoluminescence spectroscopy and picosecond time-resolved emission studies indicate that the observed tunable emission arises as a consequence of incomplete energy transfer between the di-ureasil and the CP dopant, resulting in emission from both species on direct excitation of the di-ureasil matrix. The facile synthetic approach and tunable emission demonstrate that CP-di-ureasils are a highly promising route to white-light-emitters that simultaneously improve the stability and reduce the complexity of CP-based multilayer device architectures.