jp8b07083_si_001.pdf (1.2 MB)
Enhancing the Electroluminescent Efficiency of Acridine-Based Donor–Acceptor Materials: Quasi-Equivalent Hybridized Local and Charge-Transfer State
journal contribution
posted on 2018-07-30, 00:00 authored by Changjiang Zhou, Dengli Cong, Yu Gao, Haichao Liu, Jinyu Li, Shitong Zhang, Qing Su, Qiaolin Wu, Bing YangExcited-state
properties (characteristics and composition) play
a crucial role in luminescence properties of the new-generation organic
light-emitting materials. As a special excited species, the hybridized
local and charge-transfer (HLCT) state is composed of locally excited
(LE) state and charge-transfer (CT) state, which can harvest simultaneous
high photoluminescence (PL) efficiency and high exciton utilization
in organic light-emitting diodes. In this work, we designed and synthesized
three donor (D)–acceptor (A) compounds with different donor
units and a typical electron-deficient unit acridine as the acceptor
unit to investigate the different hybridization statuses among them.
As is revealed by the molecular design, the three compounds precisely
show the different hybridization statuses: LE-dominated hybridization
(CZP-1AC), quasi-equivalent HLCT (qHLCT, TPA-1AC), and CT-dominated
hybridization (PTZ-1AC). As a result, TPA-1AC exhibits the highest
PL efficiency and multifold device performance, meriting from the
most effective suppression of nonradiative processes that originated
from a qHLCT state due to the strong interstate coupling and the small
energy gap between LE and CT states. This work not only provides a
comprehensive insight into the hybridization formation and a fine
modulation in HLCT state composition but also provides a valuable
strategy to design new-generation, low-cost, high-performance organic
electroluminescence materials based on lowly emissive chromophores
of D or A.