Theoretical study on photophysical properties of multifunctional electroluminescent molecules with different pi-conjugated bridges.
The photophysics of a series of molecular organic light-emitting diodes (OLEDs) has been studied by theoretical calculation. These molecular OLEDs have been integrated by an electron- and hole-transporting components as well as an emitting components into the donor-pi-acceptor (D-pi-A) structures: 2-carbazolyl-7-dimesitylboryl-9,9-diethylfluorene (1), trans-4'-N-carbazolyl-4-dimesitylborylstilbene (2), and trans-2-[(4'-N-carbazolyl)styryl]-5-dimesitylborylthiophene (3). To reveal the relationship between the structures and properties of these multifunctional electroluminescent materials, the ground- and excited-state geometries were optimized at the B3LYP/6-31G(d), HF/6-31G(d), and CIS/6-31G(d) levels, respectively. The ionization potentials and electron affinities were computed. The mobilities of hole and electron in these compounds were studied computationally based on the Marcus electron transfer theory. The lowest excitation energies (E(g)) and the maximum absorption and emission wavelengths of these compounds were calculated by time-dependent density functional theory methods. The solvent effect on the emission spectra of these compounds was considered by a polarizable continuum model. As a result of these calculations, it was concluded that the electron injections of these compounds are much easier than Mes(2)B[p-4,4'-biphenyl-NPh(1-naphthyl)], and the diethylfluorene-based compound has higher electron mobility and better equilibrium properties as compared to the stilbene-based and styrylthiophene-based compounds.
Zou
Lu Yi
LY
State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
Ren
Ai Min
AM
Feng
Ji Kang
JK
Liu
Yan Ling
YL
Ran
Xue Qin
XQ
Sun
Chia Chung
CC