DFT Investigation of Triarylamine-α-cyanoacrylic Acid Compounds: Structural, Electronic, and Nonlinear Optical Properties

Using the density functional theory and finite field method, nonlinear optical properties of nine triarylamine-α-cyanocinnamic acid derivatives were investigated at the M06-2X/6-311++ G(d,p) and ωB97X-D/6-311++ G(d,p) levels of theory. Except for (E)-2-cyano-3-(4-(di([1,1'-biphenyl]-4-yl)amino)phenyl)acrylic acid (a), which had a D-π-A electronic structure, all the other eight derivatives had an A-π-D-π-A structure. The results suggest that the lowest energy transition of the nine triarylamine derivatives was the π-π* transition from the HOMO to LUMO. The absorption maxima of the derivatives in their ethanol solution were redshifted with respect to those in the gas phase. The introduction of conjugated C = C or C≡C bonds between the biphenyl unit of molecule a had a minor effect on the second-order nonlinear optical properties of the molecule. However, the introduction of C = C bond into the parent molecule improved the third-order nonlinear optical properties. The introduction of a heterocyclic ring (furan ring or thiophene ring) between the triarylamine moiety and the branched chain containing the cyanocinnamic acid group enhanced the second- and third-order nonlinear optical properties; especially, the second- and third-order polarisabilities of molecules b3 and c3, which were obtained by introducing a thiophene ring, were the highest. The second- and third-order polarisabilities of b3 were 0.13 × 10⁵ and 27.13 × 10⁵ a.u., respectively, while those of c3 were 0.14 × 10⁵ and 28.10 × 10⁵ a.u., respectively. This suggests that b3 and c3 have desirable second- and third-order nonlinear optical properties and can be used for designing efficient second- and third-order nonlinear optical materials.

A supramolecular assembly of metal-free organic dye with zinc porphyrin chromophore for dye-sensitized solar cells

The supramolecular system has superior performance in improving spectral response and reducing charge recombination, which could be a promising and convenient method to improve the performance of DSSCs.

Enhanced performance of dye-sensitized solar cells with Y-shaped organic dyes containing di-anchoring groups

Introducing two carboxylic acid anchors by the benzene bridge in the design of sensitizers can effectively improve the performance of DSSCs.

Investigation of the photoinduced electron injection processes for natural dye-sensitized solar cells: the impact of anchoring groups

In this study, nine different natural dyes having various anchoring groups were extracted from various plants and used as photo-sensitizers in DSSC applications. The photovoltaic parameters were investigated as a function of these anchoring groups.