TY  - JOUR
T1  - Superior efficiency and long-lifetime in non-exciplex organic light-emitting diodes enabled by accelerated Dexter energy transfer
AU  - Song, You Na
AU  - Park, Sangwook
AU  - Lee, Jaehyun
AU  - Park, Jongwook
AU  - Kim, Taekyung
JO  - Chemical Engineering Journal
VL  - 511
SP  - 162011
PY  - 2025
DA  - 2025/05/01/
SN  - 1385-8947
DO  - https://doi.org/10.1016/j.cej.2025.162011
UR  - https://www.sciencedirect.com/science/article/pii/S1385894725028372
KW  - Organic light-emitting diodes
KW  - Lifetime
KW  - Phosphorescence
KW  - Non-exciplex
KW  - Dexterenergy transfer
AB  - Triplets harvested from the exciplex state are transferred to the dopant via Förster resonance energy transfer (FRET), leading to high exciton utilization efficiency. However, “dark triplets” that fail to undergo up-conversion to singlets act as degradation factors due to slow electron exchange mechanism of Dexter energy transfer (DET). Thus, it is widely accepted that boosting FRET and suppressing DET is critical in organic light-emitting diode (OLED) performance. Here, we aim to challenge such a generally acknowledged concept by activating and accelerating DET processes. Non-exciplex-based OLEDs were fabricated using an n-type host, 4-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)phenyl)triphenylsilane. Due to the absence of exciplex formation, the DET channel of the n-type host was fully activated. The DET rate of 9.57 × 106/s in the non-exciplex system, comparable to the FRET rate in the exciplex system, enhances exciton utilization by converting dark triplets into “bright triplets,” reducing the dark triplet population. As a result, the enhanced efficiency and lifetimes were achieved simultaneously. Our non-exciplex phosphor-sensitized-fluorescent (PSF)-OLED achieved an external quantum efficiency of 26.1 % and an LT80 of 216 h, six times longer than that of exciplex-based PSF-OLEDs. This study presents a novel pathway for high-efficiency, long-lifetime blue phosphorescent OLEDs through accelerated DET, previously known for negatively impacting device performance.
ER  -