High efficiency of white organic light-emitting diodes achieved by reforming the structure to balance the amount of carriers in single emission layer

• Main Authors: Szu-Chi Huang, 黃思齊
• Other Authors: Su-Hua Yang
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/80345200108575348622

碩士 === 國立高雄應用科技大學 === 電子工程系 === 99 === We have successfully fabricated a high luminance, high efficiency and low driving-voltage white organic light-emitting diode with the structure of single emission layer by solution method. This theme contains several subjects, including: 1. the choice of the most suitable organic material for transport layer; 2. the optimal thickness preparation of the transport layer; 3. the realization of white light emission by precisely adjusting the concentrations of guest materials (blue dopant BCzVB, red dopant DCJTB) doped into host material; 4. the improvement in electroluminescent properties using the incomplete energy transfer between host and guest materials; 5. the enhancement in device performances by employing LiF as the electron injection layer; 6. the achievement on better color purity of the device using CBP as the hole blocking layer. Furthermore, for single-emission-layer white OLEDs which contain hosts and dopants, a common problem faced is the need for very precise control over the concentrations of the dopants. Thus, to overcome the aforementioned problem, the devices were fabricated utilizing vapor deposition with solvent premixed deposition source. Accordingly, a pure white OLED can be easily realized with single-emission-layer; moreover, the fabrication process will be shortened and simplified for device fabrication. Consequently, the run-to-run variability caused by subtle variations in process conditions will be reduced.