Electronic Structure and Optical Properties of Designed Photo-Efficient Indoline-Based Dye-Sensitizers with D–A−π–A Framework

Abstract

Seven D−A−π−A-based indoline (IND) dyes that were designed via quantitative-structure−property relationship modeling have been comprehensively investigated using computational approaches to evaluate their prospect of application in future dye-sensitized solar cells (DSSCs). An array of optoelectronic properties of the isolated dye and dyes adsorbed on a TiO 2 cluster that simulates the semiconductor were explored by density functional theory (DFT) and time-dependent DFT methods. Light absorption spectra, vertical dipole moment, shift of the conduction band of semiconductor, excited state lifetime, driving force of electron injection, photostability of the excited state, and exciton binding energy were computed. Our study showed that the presence of an internal acceptor such as pyrido[3,4-b]pyrazine (pyrazine) would influence greater the open circuit voltage (V OC ), compared to the benzothiadiazole moiety. Considering the balance between the V OC and J SC (short circuit current) along with the all calculated characteristics, the IND3, IND5, and IND10 are the most suited among the designed dyes to be used as potential candidates for the photo-efficient DSSCs. The present study provides the results of rational molecular design followed by exploration of photophysical properties to be used as a valuable reference for the synthesis of photo-efficient dyes for DSSCs.

The Synthesis and Theoretical Investigation of Functionalized N,N′‐Arylthioalkylisoindigo Derivatives

“…To facilitate an efficient electron injection at the interface and impede the undesired recombination of charges, the HOMO energies of should be more negative than the redox potential (−4.8 eV) while the LUMO level must be higher than the conduction band edge (−4.05 eV) of the intended semiconductor [20] . The results given in Figure 3 and Table 1 demonstrated that the HOMO energies of the studied dyes are in the range between −5.78 eV and −6.01 eV which are helpful to the spontaneity of regeneration of the synthesized‐dye.…”

Recent developments in metal‐free organic sensitizers derived from carbazole, triphenylamine, and phenothiazine for dye‐sensitized solar cells

“…30 Thus, metal-free organic sensitizers have drawn greater attention over metal-based organic sensitizers due to their low toxicity, high structural flexibility, environment friendly nature, high MECs, and facile synthesis. 31,32 It is to be noted that previously, several chromophores such as indoline, 33,34 coumarin, 35,36 phenothiazine, 37,38 carbazole, 39,40 triarylamine, 41,42 tetrathiafulvalene, 43,44 etc were used in the assembly of organic sensitizers. Better structure-property relationship elucidation will encourage the better use of these dyes in DSSCs.…”

Recent advances in theoretical investigation of titanium dioxide nanomaterials. A review

“…The systematical theoretical study of seven D−A−π−A-based indoline (IND) dyes (Fig. 33a) was comprehensively investigated via quantitative-structure−property relationships to evaluate their prospect of application in DSSCs [195]. Adapted with permission from [195].…”

“…33d). Considering the balance between the V OC and J SC (short circuit current), the IND3, IND5, and IND10 dyes were suggested as the most suited to be utilized as potential candidates for DSSC [195].…”

“…Colored boxes are indicating constituents of the framework. Blue (D), green (A or internal acceptor), red (A or cyanoacrylic acid), and the fragment in between red and green box is the π-spacer, (b-c) Fully relaxed optimized geometry of the model TiO 2 cluster (Ti 16 O 34 H 4 ) and the IND2/TiO 2 -cluster with bridged bidentate mode, (d) Energy alignment of the IND dyes with respect to TiO 2 along with the CDD of the dyes/TiO 2 -cluster complex and CB of TiO 2 .Adapted with permission from[195]. Copyright © 2019 American Chemical Society.…”