Dye chemistry with time-dependent density functional theory

Abstract

In this perspective, we present an overview of the determination of excited-state properties of "real-life" dyes, and notably of their optical absorption and emission spectra, performed during the last decade with time-dependent density functional theory (TD-DFT). We discuss the results obtained with both vertical and adiabatic (vibronic) approximations, choosing relevant examples for several series of dyes. These examples include reproducing absorption wavelengths of numerous families of coloured molecules, understanding the specific band shape of amino-anthraquinones, optimising the properties of dyes used in solar cells, mimicking the fluorescence wavelengths of fluorescent brighteners and BODIPY dyes, studying optically active biomolecules and photo-induced proton transfer, as well as improving the properties of photochromes.

Photophysics of BODIPY Dyes as Readily-Designable Photosensitisers in Light-Driven Proton Reduction

“…This overestimation of the excitation energies is reasoned by the lack of TDDFT to address the multi-configurational character and by the inability to describe double excitations (DE). Typically, for BODIPY dyes, TDDFT overestimates the excitation energy of the bright absorption band [30][31][32][33] (measured in THF) in the visible region centred at 497 nm (2.49 eV), assigned to the excitation into the S 1 state at 419 nm (2.96 eV), by approximately 0.5 eV, similar hypsochromic shifts were observed for the UV bands (see states S 2 -S 4 in Table S2). This overestimation of the excitation energies is reasoned by the lack of TDDFT to address the multi-configurational character and by the inability to describe double excitations (DE).…”

“…Assessing excited state properties by virtue of computationally affordable time-dependent density functional theory (TDDFT) simulations is a well-known challenge for BODIPY dyes [30][31][32][33]. Therefore, following the computational protocol presented in [33], the fully-relaxed (singlet) ground state equilibrium structure of 2 was obtained using the hybrid-functional PBE0 [45][46][47] and the cc-pVTZ triple-ξ basis set [48,49] as implemented in the Gaussian 09 program [50], while effects of interaction with the THF solvent (ε = 7.4257, n = 1.4070) were taken into account by the integral equation formalism of the polarizable continuum model (IEFPCM) [51].…”

Choosing an atomic basis set for TD-DFT, SOPPA, ADC(2), CIS(D), CC2 and EOM-CCSD calculations of low-lying excited states of organic dyes

“…The latter approach undoubtedly remains the most popular approach for ES, as it allows a rapid estimation of transition energies and ES properties for a limited computational effort, even for relatively large molecules (ca. 100-400 atoms) [16]. Despite considerable successes, especially in designing new dyes, TD-DFT suffers from a series of limitations, e.g., its inadequacy for ES presenting a significant double-excitation character and its strong functional dependence-the obtained ES energies and properties are strongly dependent on the selected exchange-correlation functional [17].…”

Can chemometrics be used to guide the selection of suitable DFT functionals?

“…A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 6,7,8,9,10,12,14,16,18,20 Supervised analysis. Since jCompoundMapper (software for calculating fingerprints) outputs feature maps in a sparse format that is amenable for data mining, the aforementioned fingerprinting schemes were tested for their discriminant ability using support vector classification as implemented in the LIBSVM software [68].…”

“…Although a broad palette of XC functionals based on the local density approximation (LDA), generalized gradient approximation (GGA) and hybrid-DFT variants have been introduced [16], they are generally found to be accurate for only a limited set of molecular systems or those that they are calibrated for [17]. While minor effects due to the choice of the atomic basis set have been observed, in most cases, parameters computed using larger basis sets are found to be closer to experimentally determined values and higher-level theoretical methods.…”