Predicting phosphorescence quantum yield for Pt(II)-based OLED emitters from correlation function approach
Journal
Journal of Physical Chemistry C
Date
2019.04.05
Abstract
We report a new formulation for Golden Rule based predictions of photoluminescence
quantum yields (PLQY) of phosphorescent emitters containing a heavy element,
and its implementation compatible with first-principle computation frameworks. The
main components of PLQY (i.e., phosphorescent rate and inter-system crossing rate
from the lowest triplet state to the ground singlet state) are obtained through correlation
functions calculated in time domain, and the relativistic effects are also considered
using the relativistic effective core potentials. The spin？orbit coupling is treated in
a perturbative manner to generate spin？orbit corrected, two-component T1 substates
within single-excitation theory, where the electronic transition dipole moments and the
non-Born-Oppenheimer coupling matrix elements to the S0 state are computed. We
applied this new approach to photophysical properties of 34 Pt(II) complexes designed
for the organic light-emitting diode (OLED) applications, and observed a good agreement
between predictions and experiments over diverse scaffolds. Furthermore, to gain
insight into the source of nonradiative characteristics, an analysis based on the decomposition
of contributions of the nuclear vibrations and the electronic structure of
excited states to the non-Born？Oppenheimer coupling for two repesentative complexes
from given set is also presented and discussed.