Bazı fosfor/organik boya kombinasyonlarının polimerik matrikslerde optik özelliklerinin ve stabilitelerinin araştırılması

Phosphors are commercially important chemicals because they are used as raw materials in mobile phones, personal computers, LCD screens, light emitting diode (LED) and white light emitting diode (WLED) technologies. In this thesis, commercially available phosphors of Lu3Al5O12:Ce3+ (LuAG:Ce3+), (Y,Gd)3Al5O12:Ce3+ (YAG:Ce3+) and CaAlSiN3:Eu2+ (CASN:Eu2+) were investigated to enhance their spectral properties rather than the known approaches. The green, yellow and red phosphors were chosen to represent a large spectral range available in the screen technologies as well as LED applications. All phosphors were prepared in thin film form in a polymethyl methacrylate (PMMA) matrix. The light harvesting materials of nano-scale ZnO and CuO, have been used to improve the spectral properties of the LuAG:Ce3+ and YAG:Ce3+. In this process, fluorescence, phosphorescence, and excited state lifetimes were monitored and promising experimental results were obtained. Mechanisms indicating possible energy transfers between the species have been revealed. In the second part of the thesis, the energy transfer between phosphors and Tris (1,10-phenanthroline) ruthenium (II) hexafluorophosphate dye (Ru(phen)3PF6) has been investigated. The binary blends of the LuAG:Ce3+, YAG:Ce3+ and CASN:Eu2+ with the Ru(phen)3PF6 exhibited promising results in the presence of the ionic liquid (IL). Long-term photo stabilities of the composites supported with the IL were investigated during 8 months. No significant effect of the IL on photo-stability levels was detected.