All‐Solution‐Processed Red and Orange‐Red Organic Light‐Emitting Diodes with High‐Efficiencies: The Effect of Mixed‐Host Emissive Layers and Thermal Annealing Treatment

Autor: Meu Rurng Tseng, Heh Lung Huang, Hsin-Fei Meng, Yu Chiang Chao, Yu Fan Chang, Chao Hsuan Chen, Lan Sheng Yang, Teng-Chih Chao, Chih-Wei Luo, K.P.O. Mahesh, Si Yi Liao, Hsiao-Wen Zan, Mu Chun Niu, Hsiao Tso Su, Sheng-fu Horng
Rok vydání: 2019
Předmět:
Zdroj: ChemPlusChem. 84:1375-1383
ISSN: 2192-6506
DOI: 10.1002/cplu.201900248
Popis: The instability of the organic light-emitting diodes (OLEDs) during operation can be attributed to the existence of point defects on the organic layers. In this work, the effect of mixed-host emissive layer and the thermal annealing treatment were investigated to eliminate defects and to boost the device performance. The mixed-host system includes 4,4',4''-tri (9-carbazoyl) triphenylamine (TCTA) and 2,7-bis(diphenylphosphoryl)-9, 9'-spirobi[fluorene] (SPPO13). The mixed-host emissive layer with thermal annealing treatment showed low roughness and few pinholes, and the devices fabricated from this emissive layer exhibited high efficiencies, high stabilities, and long lifetimes. The red and orange-red OLEDs exhibited efficiencies of 13.9 cd/A and 24.35 cd/A, respectively. The longest half-lifetime (L0 =500 cd/m2 ) of the red and orange-red OLEDs were 158 h and 180 h, respectively. Efforts were made to solve problems in large-area coating and to reduce the number of defects on in organic layer. Large-active-area (active area=3 cm×4 cm) red phosphorescent OLEDs (PhOLEDs) devices were realized with very high current efficiency up to 9 cd/A.
Databáze: OpenAIRE
Externí odkaz:
Nepřihlášeným uživatelům se plný text nezobrazuje