Red Organic Light-emitting Study

Organic light-emitting diode(OLED)has become become a new important area due to its potential applications in flat panel displays. For full color display, the tricolors, red, green and blue (RGB) light emitting have been investigated intensively. so far, the reported blue and green OLEDs have shown sufficient performance for commercial displays. However, the performance of red OLED still need to be improved. Three kinds of red OLEDs and their characteristics are studied in this thesis.The requirments for the host and guest materials in a doped OLED are discussed according to F?rster energy transfer theory. Red organic EL devices based on Alq3 doped with DCM are fabricated. The divices show bright red emission and good rectification. The good characteristics are attributed to the effective energy trransfer from Alq3 to DCM because of their reasonable energy level structure and further the overlap of the absorbtion of DCM and the PL of Alq3. In order to improve color purity, rare earth materials with narrow emission spectra have attracted great intresting. Different methods have been eployed to fabricated OLEDs of Eu3+ complex in present work. Red OLEDs with narrow emission band at 612nm are obvserved in PVK:Eu3+. The physical process of rare earth light emitting is discussed in experiment and theory.An organic salt trans-4-[P-(N-ethyl-N-(hydroxylethyl)-amino) styryl]-N- methylpyridinium tetraphenylborate (ASPT) has been synthesized. The physical and chemical properties of ASPT are investigated. Monolayer and multilayer OLEDs based on ASPT illustrated considerably enhancement of carrier injection and high electroluminecent efficience. The efficiency of the device ITO/ASPT/Al is about 4 times as large as the corresponding Alq3 device and multilayer device show good characteristic. Polarization mechanism of organic ionic salt is discussed. The imvestigation on organic salt is benefit to widen and select OLED materials...