Pyran-Squaraine as Photosensitizers for Dye-Sensitized Solar Cells: DFT/TDDFT Study of the Electronic Structures and Absorption Properties

Table 3

Second-order perturbation interactions () obtained for squaraine dyes at B3LYP/6–311++G** from NBO calculations.

Donor	Acceptor		Donor	Acceptor
		1.49			1.46
		2.49			2.65
		27.14			2.68
		3.75			1.2
		19.57			2.83
		32.84			4.49
		20.26			21.47
		281.08			3.69
		122.46			2.99
		24.95			1.03
		4.53			17.70
		8.2			16.82
		1.36			12.05
		4.92			5.34
		8.92			21.59
		7.69			29.78
		9.79			7.76
		11.28			7.14
		8.96			6.39
		15.82			6.87
		9.16			19.68
		26.54			7.2
		8.82