jz0c00451_si_001.pdf (2.43 MB)
Achievement of High-Level Reverse Intersystem Crossing in Rubrene-Doped Organic Light-Emitting Diodes
journal contribution
posted on 2020-03-25, 16:33 authored by Xiantong Tang, Ruiheng Pan, Xi Zhao, Hongqiang Zhu, Zuhong XiongUsing
the fingerprint magneto-electroluminescence trace, we observe
a fascinating high-level reverse intersystem crossing (HL-RISC) in
rubrene-doped organic light-emitting diodes (OLEDs). This HL-RISC
is achieved from high-lying triplet states (T2,rub) transferred
from host triplet states by the Dexter energy transfer to the lowest
singlet states (S1,rub) in rubrene. Although HL-RISC decreases
with bias current, it increases with lowering temperature. This is
contrary to the temperature-dependent RISC from conventional thermally
activated delayed fluorescence, because HL-RISC is an exothermic process
instead. Moreover, owing to the competition of exciton energy transfer
with direct charge trap, HL-RISC changes nonmonotonically with the
dopant concentration and increases luminous efficiency to a maximum
at 10% of rubrene, which is about ten times greater than that from
the pure-rubrene device. Additionally, the HL-RISC process is not
observed in bare rubrene-doped films because of the absence of T2,rub. Our findings pave the way for designing highly efficient
orange fluorescent OLEDs.
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host triplet statesdopant concentrationhigh-lying triplet statesOLEDrubrene-doped filmsDexter energy transfersinglet statesRubrene-Doped Organic Light-Emitting Diodestemperature-dependent RISCHL-RISC changes nonmonotonicallyHL-RISC decreaseslight-emitting diodesexciton energy transferfingerprint magneto-electroluminescence tracepure-rubrene deviceHL-RISC processcharge trap
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