Management of Delayed Fluorophor-Sensitized Exciton Harvesting for Stable and Efficient All-Fluorescent White Organic Light-Emitting Diodes.
ACS Appl Mater Interfaces
; 12(14): 16736-16742, 2020 Apr 08.
Article
de En
| MEDLINE
| ID: mdl-32193927
ABSTRACT
White organic light-emitting diodes (WOLEDs) using thermally activated delayed fluorescence (TADF)-based single emissive layer (SEL) have attracted enormous attention because of their simple device structure and full exciton utilization potential for high efficiency. However, WOLEDs made of an all-TADF SEL usually exhibit serious efficiency roll-off and poor color stability due to serious exciton-annihilation and unbalanced radiative decays of different TADF emitters. Herein, a new strategy is proposed to manipulate the TADF-sensitized fluorescence process by combining dual-host systems of high triplet energy with a conventional fluorescent emitter of complementary color. The multiple energy-funneling paths are modulated and short-range Dexter energy transfer is largely suppressed due to the steric effect of peripheral tert-butyl group in the blue TADF sensitizer. The resulting all-fluorescent WOLEDs achieve an unprecedentedly high external quantum efficiency of 21.8% with balanced white emission of Commission Internationale de l'Eclairage coordinate of (0.292, 0.343), accompanied with good color stability, reduced efficiency roll-off, and prolonged operational lifetime. These findings demonstrate the validity of this strategy for precisely allocating the exciton harvesting in SEL WOLEDs.
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Langue:
En
Journal:
ACS Appl Mater Interfaces
Sujet du journal:
BIOTECNOLOGIA
/
ENGENHARIA BIOMEDICA
Année:
2020
Type de document:
Article
Pays d'affiliation:
Chine