Premium
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
Author(s) -
Chang YuFan,
Yang LanSheng,
Su HsiaoTso,
Liao SiYi,
Niu MuChun,
Mahesh K. P. O.,
Chen ChaoHsuan,
Chao YuChiang,
Meng HsinFei,
Huang HehLung,
Chao TengChih,
Tseng MeuRurng,
Luo ChihWei,
Zan HsiaoWen,
Horng ShengFu
Publication year - 2019
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201900248
Subject(s) - oled , triphenylamine , materials science , diode , optoelectronics , phosphorescent organic light emitting diode , annealing (glass) , phosphorescence , layer (electronics) , nanotechnology , optics , composite material , physics , fluorescence
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 (L 0 =500 cd/m 2 ) 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.