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Article Dans Une Revue Journal of Chemical Theory and Computation Année : 2015

Theoretical Rationalization of the Singlet-Triplet Gap in OLEDs Materials: Impact of Charge-Transfer Character

Résumé

New materials for OLED applications with low singlet-triplet energy splitting have been recently synthesized in order to allow for the conversion of triplet into singlet excitons (emitting light) via a Thermally Activated Delayed Fluorescence (TADF) process, which involves excited-states with a non-negligible amount of Charge-Transfer (CT). The accurate modeling of these states with Time-Dependent Density Functional Theory (TD-DFT), the most used method so far because of the favorable trade-off between accuracy and computational cost, is however particularly challenging. We carefully address this issue here by considering materials with small (high) singlet-triplet gap acting as emitter (host) in OLEDs and by comparing the accuracy of TD-DFT and the corresponding Tamm-Dancoff Approximation (TDA), which is found to greatly reduce error bars with respect to experiments thanks to better estimates for the lowest singlet-triplet transition. Finally, we quantitatively correlate the singlet-triplet splitting values with the extent of CT, using for it a simple metric extracted from calculations with double-hybrid functionals, that might be applied in further molecular engineering studies.

Dates et versions

hal-01411679 , version 1 (07-12-2016)

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Citer

Monica Moral, Luca Muccioli, Wonjoon Son, Yoann Olivier, Juan-Carlos Sancho-Garcia. Theoretical Rationalization of the Singlet-Triplet Gap in OLEDs Materials: Impact of Charge-Transfer Character. Journal of Chemical Theory and Computation, 2015, 11 (1), pp.168-177. ⟨10.1021/ct500957s⟩. ⟨hal-01411679⟩
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