Hi All,
We will have a visit of postdoc candidate next Monday. The abstract of the talk is pasted
below. Please let me know if you want to meet with her and/or have a lunch (12pm-1:30pm)
on Monday.
Cheers,
Dennis
Accurate treatment of charge-transfer excitations and thermally activated delayed
fluorescence using the particle-particle random phase approximation
Abstract: Thermally-activated delayed fluorescence (TADF) is a mechanism that increases
the efficiency of light emission in organic light-emitting diodes by harnessing both
singlet and triplet excitons. TADF is facilitated by a small energy difference between the
first singlet (S1) and triplet (T1) excited states [*E(ST)], which is minimized by spatial
separation of the donor and acceptor moieties. The resultant charge-transfer (CT) excited
states are difficult to model using semilocal exchange-correlation (xc) functionals
combined with time-dependent density functional theory because of the delocalization error
present in these approximate methods. In this talk I will review approaches to model CT
transitions in TADF emitters and introduce the results from the particle-particle random
phase approximation (pp-RPA). The pp-RPA is able to capture CT states and accurately
reproduce excitation energies which is attributed to the consistent treatment of both
ground and excited states. Qualitative characterization of excited states as CT or locally
excited, in comparison with experiment, and interesting structural features of TADF
molecules will be discussed as well.
Speaker: Rachael Al-Saadon
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