Abstract
Bipolar host molecules capable of transporting both charges can meet the requirement of balancing the charge density for simplification of high performance PHOLEDs. In this thesis, we have developed and designed a series of the red and green PhOLEDs by introducing different hole and electron buffer layers to the host material CzPPQ and CzPPCzQ. In addition, For doped WOLEDs, a precise control over the doping ratio for each dopant emitter throughout the entire active area is required. However, the larger the number of EMLs or dopants involved, the more difficult and costly the manufacturing process. Accordingly, the use of only a single-dopant or a non-doped EML (ND-EML) have been proposed. CzP-FPt exhibited highly efficient orange light emission and wide spectral coverage in the visible region, which motivated us to fabricate ND-WOLEDs from its phosphor thin film. We introduced an NPB barrier layer to device to prevent electron and exciton quenching at the ITO anode, and carefully adjusted the organic layer thicknesses to let exciton recombination taken place in the blue fluorescence PPP layer. The white EL of final device exhibited an excellent visible spectrum coverage with a full-width at half-maximum of 194 nm and a CRI of 80.