Effect of carboxylic acid and cyanoacrylic acid as anchoring groups on Coumarin 6 dye for dye-sensitized solar cells: DFT and TD-DFT study

Abstract

Starting with Coumarin-6 dye, two novel D-π-A organic dyes C6X and C6N have been designed by attaching carboxylic acid and cyanoacrylic acid groups as anchoring groups to Coumarn-6 dye, respectively, to understand their potential use in dye-sensitized solar cells (DSSCs). The electronic structure and photophysical and photovoltaic properties of the novel designed dyes were studied using density functional theory DFT and time-dependent density functional theory TD-DFT with the Becke3-Parameter-Lee–Yang–Parr (B3LYP) functional and the 6-31G (d, p) basis set. Optimized structure and electronic properties (highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital (ELUMO), and energy difference (Eg) between HOMO and LUMO) were calculated showing that C6N has the smallest band gap with the larger absorption region. Density of states (DOS), molecular electrostatic potential (MEP), natural bond orbital (NBO) analysis, non-linear optical (NLO) properties, UV–vis spectra, as well as some crucial parameters affecting the photovoltaic performance of DSSCs, such as light-harvesting efficiency (LHE), electron injection driving force (ΔGinject), dye regeneration driving force(ΔGreg), and the excited state life time(τe), were calculated to study the effect of the anchoring group on the DSSC performance. Additionally, the adsorption of C6X and C6N dyes on the TiO2 anatase (101) surface and the mechanism of electron injection were also investigated using a dye–(TiO2)9 cluster model using TD-B3LYP calculation. The calculated adsorption energies of the dyes suggest a strong adsorption of dyes to a TiO2 surface. The results show that C6N may be theoretically a good candidate as sensitizer of DSSC application.

Enhancement of dielectric relaxation and AC conductivity of Te(1−x)(GeSe0.5)Scx (0 ≤ x ≤ 0.15) chalcogenide glasses by a rare-earth dopant

“…A shift in the Fermi level and an increase in charge carrier concentration might result from the presence of an additive. 61,62 Such findings are in agreement with the previously reported results. 47,52,63…”

High-Efficiency and Low-Energy-Loss Organic Solar Cells Enabled by Tuning the End Group Modification of the Terthiophene-Based Acceptor Molecules to Enhance Photovoltaic Properties

“…One key factor influencing the charge transfer efficiency is the excited state lifetime (τ). A chromophore with extended τ values might exhibit more convenient charge transfer abilities . The τ values of RM and all modeled chromophores AM1–AM6 were calculated by eq , and the values are represented in Table . bold-italicτ = bold1.499 / bold-italicf E ex 2 …”

“…A chromophore with extended τ values might exhibit more convenient charge transfer abilities. 53 The τ values of RM and all modeled chromophores AM1−AM6 were calculated by eq 7, and the values are represented in Table 5. Here, E elaborates on the energy of the transition at different excited states, and f depicts the oscillator strength of the excited state.…”

Optical and electronic properties enhancement via chalcogenides: promising materials for DSSC applications

“…It is a requirement that charge injection time should be shorter than the excited state decay to the ground state for e cient charge injection before radiative or photochemical reactions occur [39][40][41][42]. The τ (ns) of a sensitizer can be calculated by using the following relation [43][44][45][46][47][48]:…”