Dou D, Wu P, Liao Z, Hao J, Zhang J, Wang Z. A thermally activated delayed fluorescence exciplex to achieve highly efficient and stable blue and green phosphorescent organic light-emitting diodes.
RSC Adv 2019;
9:23810-23817. [PMID:
35530600 PMCID:
PMC9069484 DOI:
10.1039/c9ra02875g]
[Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 06/22/2019] [Indexed: 12/26/2022] Open
Abstract
The development of a thermally activated delayed fluorescence (TADF) exciplex with high energy is of great significance in achieving highly efficient blue, green, and red organic light-emitting diodes (OLEDs) for use in full-color displays and white lighting. Highly efficient and stable blue and green phosphorescent OLEDs were demonstrated by employing a TADF exciplex (energy: 2.9 eV) based on 4-substituted aza-9,9′-spirobifluorenes (aza-SBFs). Blue PhOLEDs demonstrated a maximum current efficiency (CE) of 47.9 cd A−1 and an external quantum efficiency (EQE) of 22.5% at 1300 cd m−2 (2.5 times the values of aza-SBF-based systems), with the best blue PhOLED demonstrating a CE, power efficiency (PE) and EQE of 60.3 cd A−1, 52.7 lm W−1, and 26.2%, respectively. Green PhOLEDs exhibited a CE of 78.1 cd A−1 and EQE of 22.5% at 9360 cd m−2, with the best green PhOLED exhibiting a maximum CE, PE, and EQE of 87.4 cd A−1, 101.6 lm W−1, and 24.5%, respectively. The device operational lifetime was improved over 17-fold compared to reference devices because of the high thermal stability of the materials and full utilization of the TADF exciplex energy, indicating their potential for application in commercial OLEDs.
A high energy TADF exciplex (415 nm) based on aza-spirobifluorene derivatives was demonstrated to achieve efficient and stable PhOLEDs.![]()
Collapse