Performance of TDDFT Vertical Excitation Energies of Core-Substituted Naphthalene Diimides.

Ayush K Narsaria,Koop Lammertsma,F Matthias Bickelhaupt,Julian D Ruijter,Trevor A Hamlin,Célia Fonseca Guerra,Andreas W Ehlers

doi:10.1002/jcc.26188

Abstract

We have evaluated the performance of various density functionals, covering generalized gradient approximation (GGA), global hybrid (GH) and range‐separated hybrid (RSH), using time dependent density functional theory (TDDFT) for computing vertical excitation energies against experimental absorption maximum (λmax) for a set of 10 different core‐substituted naphthalene diimides (cNDI) recorded in dichloromethane. The computed excitation in case of GH PBE0 is most accurate while the trend is most systematic with RSH LCY‐BLYP compared to λmax. We highlight the importance of including solvent effects for optimal agreement with the λmax. Increasing the basis set size from TZ2P to QZ4P has a negligible influence on the computed excitation energies. Notably, RSH CAMY‐B3LYP gave the least error for charge‐transfer excitation. The poorest agreement with λmax is obtained with semi‐local GGA functionals. Use of the optimally‐tuned RSH LCY‐BLYP* is not recommended because of the high computational cost and marginal improvement in results.

Highlights

In recent years, organic dyes have found applications that extend far beyond their traditional use such as in optoelectronic devices ranging from light emitting diodes[1,2,3,4,5] to dye sensitized solar cells.[6,7,8]Ayush K
In this paper we present a systematic time dependent density functional theory (TDDFT) study of coresubstituted naphthalene diimides which are well known for their tunable absorption and emission properties, ranging over the entire visible to near-infrared spectrum.[27,28,29,30,31,32]
We evaluated the performance of OT-range-separated hybrid (RSH) LC-BLYP*, where * represents ab-initio tuned range-separation parameter γ in LC-BLYP based on the IP theorem of DFT,[60,61,62,63] details of which are provided

Summary

Introduction

Organic dyes have found applications that extend far beyond their traditional use such as in optoelectronic devices ranging from light emitting diodes[1,2,3,4,5] to dye sensitized solar cells.[6,7,8]Ayush K. We have computed the lowest dipole-allowed singlet electronic excitation energies for 10 different core-substituted naphthalenediimides (cNDI; shown in Figure 1) in the gas- (Evert-abso) and in the condensed-phase (Evert-abso[DCM]) using linear-response TDDFT and compared these to experimental UV/Vis absorption maximum λmax values recorded in dichloromethane (DCM).[40] The calculations have been performed with a selection of generalized gradient approximation (GGA), global hybrid (GH), range-separated hybrid (RSH) and optimally-tuned range-separated hybrid (OT-RSH) functionals.

Results

Conclusion