Understanding the effects of electronic polarization and delocalization on charge-transport levels in oligoacene systems

Christopher Sutton, Naga Rajesh Tummala, Travis Kemper, Saadullah G. Aziz, John Sears, Veaceslav Coropceanu, Jean-Luc Brédas
2017 Journal of Chemical Physics  
Effect of the diradical character on static polarizabilities and two-photon absorption cross sections: A closer look with spin-flip equation-of-motion coupled-cluster singles and doubles method Hard-hard coupling assisted anomalous magnetoresistance effect in amine-ended single-molecule magnetic Laplace-transformed multi-reference second-order perturbation theories in the atomic and active molecular orbital basis Electronic polarization and charge delocalization are important aspects that
more » ... the charge-transport levels in organic materials. Here, using a quantum mechanical/embedded-charge (QM/EC) approach based on a combination of the long-range corrected ωB97X-D exchange-correlation functional (QM) and charge model 5 (CM5) point-charge model (EC), we evaluate the vertical detachment energies and polarization energies of various sizes of crystalline and amorphous anionic oligoacene clusters. Our results indicate that QM/EC calculations yield vertical detachment energies and polarization energies that compare well with the experimental values obtained from ultraviolet photoemission spectroscopy measurements. In order to understand the effect of charge delocalization on the transport levels, we considered crystalline naphthalene systems with QM regions including one or five-molecules. The results for these systems show that the delocalization and polarization effects are additive; therefore, allowing for electron delocalization by increasing the size of the QM region leads to the additional stabilization of the transport levels. Published by AIP Publishing.
doi:10.1063/1.4984783 pmid:29166056 fatcat:6zsemdgaxbbm3nddicnxtzfysi