Theoretical Rationalization of the Singlet–Triplet Gap in OLEDs Materials: Impact of Charge-Transfer Character
Contribuinte(s) |
Universidad de Alicante. Departamento de Química Física Química Cuántica |
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Data(s) |
21/09/2016
21/09/2016
2015
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Resumo |
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. This work was partially supported by the Samsung Advanced Institute of Technology (SAIT)’s Global Research Outreach (GRO) Program. In addition, the research in Bordeaux has been funded by the French State grant ANR-10-LABX-0042-AMADEus managed by the French National Research Agency under the initiative of excellence IdEx Bordeaux program (reference ANR-10-IDEX-0003-02), and the work in Mons was supported by the “Programme d’Excellence de la Région Wallonne” (OPTI2MAT project) and FNRS-FRFC. |
Identificador |
Journal of Chemical Theory and Computation. 2015, 11(1): 168-177. doi:10.1021/ct500957s 1549-9618 (Print) 1549-9626 (Online) http://hdl.handle.net/10045/58092 10.1021/ct500957s |
Idioma(s) |
eng |
Publicador |
American Chemical Society |
Relação |
http://dx.doi.org/10.1021/ct500957s |
Direitos |
© 2014 American Chemical Society info:eu-repo/semantics/openAccess |
Palavras-Chave | #OLEDs materials #Singlet–triplet gap #Charge-transfer character #Química Física |
Tipo |
info:eu-repo/semantics/article |