The origin of the improved efficiency and stability of triphenylamine-substituted anthracene derivatives for OLEDs: a theoretical investigation.
Herein, we describe the molecular electronic structure, optical, and charge-transport properties of anthracene derivatives computationally using density functional theory to understand the factors responsible for the improved efficiency and stability of organic light-emitting diodes (OLEDs) with triphenylamine (TPA)-substituted anthracene derivatives. The high performance of OLEDs with TPA-substituted anthracene is revealed to derive from three original features in comparison with aryl-substituted anthracene derivatives: 1) the HOMO and LUMO are localized separately on TPA and anthracene moieties, respectively, which leads to better stability of the OLEDs due to the more stable cation of TPA under a hole majority-carrier environment; 2) the more balanceable hole and electron transport together with the easier hole injection leads to a larger rate of hole-electron recombination, which corresponds to the higher electroluminescence efficiency; and 3) the increasing reorganization energy for both hole and electron transport and the higher HOMO energy level provide a stable potential well for hole trapping, and then trapped holes induce a built-in electric field to prompt the balance of charge-carrier injection.
Yang
Bing
B
State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.
Kim
Soo-Kang
SK
Xu
Hai
H
Park
Young-Il
YI
Zhang
Houyu
H
Gu
Cheng
C
Shen
Fangzhong
F
Wang
Chunlei
C
Liu
Dandan
D
Liu
Xiaodong
X
Hanif
Muddasir
M
Tang
Shi
S
Li
Weijun
W
Li
Feng
F
Shen
Jiacong
J
Park
Jong-Wook
JW
Ma
Yuguang
Y