Guest-Host Interactions in Symmetrical Carboxy Heptamethine Cyanine Dyes-Titanium Dioxide Systems: Synthesis, Theoretical Calculations, Aggregation Properties, and Application in Dye-Sensitized Solar Cells

Table 2

Photophysical data of compounds 12-14 in solution, where and are the absorption and emission wavelengths, respectively; ε (×10⁵) is the molar absorptivity coefficient, is the Stokes shift; and is the optical bandgap.

Dye	Solvent	(nm)	ε (M^-1·cm^-1)	(nm)	(nm/cm^-1)	(eV)
12	DMF	797	1.13	805	8/125	1.45
	CH3OH	787	2.46	793	6/96	1.48
13	DMF	796	1.09	800	4/63	1.45
	CH3OH	785	3.16	794	9/144	1.48
14	DMF	797	1.39	805	8/125	1.48
	CH3OH	784	3.22	793	9/145	1.45