Theoretical Study of the Local and Charge-Transfer Excitations in Model Complexes of Pentacene-C60 Using Tuned Range-Separated Hybrid Functionals

Cai-Rong Zhang; John S Sears; Bing Yang; Saadullah G Aziz; Veaceslav Coropceanu; Jean-Luc Brédas

doi:10.1021/ct500259m

Theoretical Study of the Local and Charge-Transfer Excitations in Model Complexes of Pentacene-C60 Using Tuned Range-Separated Hybrid Functionals

J Chem Theory Comput. 2014 Jun 10;10(6):2379-88. doi: 10.1021/ct500259m.

Authors

Cai-Rong Zhang^{1

2}, John S Sears¹, Bing Yang^{1

3}, Saadullah G Aziz⁴, Veaceslav Coropceanu¹, Jean-Luc Brédas^{1

4}

Affiliations

¹ School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology , Atlanta, Georgia 30332-0400, United States.
² Department of Applied Physics, Lanzhou University of Technology , Lanzhou, Gansu 730050, P. R. China.
³ State Key Laboratory of Supramolecular Structure and Materials, Jilin University , Changchun, 130012 Jilin, P. R. China.
⁴ Department of Chemistry, King Abdulaziz University , Jeddah 21589, Mekkah, Saudi Arabia.

PMID: 26580758
DOI: 10.1021/ct500259m

Abstract

The characteristics of the electronic excited states and the charge-transfer processes at organic-organic interfaces play an important role in organic electronic devices. However, charge-transfer excitations have proven challenging to describe with conventional density functional theory (DFT) methodologies due to the local nature of the exchange-correlation potentials often employed. Here, we examine the excited states of model pentacene-C60 complexes using time-dependent DFT with, on one hand, one of the most popular standard hybrid functionals (B3LYP) and, on the other hand, several long-range corrected hybrid functionals for which we consider both default and nonempirically tuned range-separation parameters. The DFT results based on the tuned functionals are found to agree well with the available experimental data. The results also underline that the interface geometry of the complex has a strong effect on the energies and ordering of the singlet and triplet charge-transfer states.