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

Table 2

Absorption wavelength (nm) and oscillator strength () calculated by different functionals using 6-311++G** basis set for squaraine acceptor dyes.

	SQ1				SQ2
	Wave length (nm)	(LHE)	MO contribution	MO coefficient	Wave length (nm)	(LHE)	MO contribution	MO coefficient
TPSSH	738.87	0.0016		0.7037	736.86	0.0009		0.704
	625.25	0.8345; (0.853)		0.687	567.26	1.1637; (0.931)		0.709
	516.08	0.1321		0.654	470.82	0.0011		0.677
				0.137
				0.214
B3LYP	630.44	0.0282		0.687	631.64	0.0035		0.702
				0.133	557.24	1.2116; (0.938)		0.708
	608.09	0.906; (0.875)		0.687	421.14	0.0003		0.299
	484.03	0.1449		0.676				0.599
				0.106
				0.141
PEBPBE	1036.32	0.0004		0.274	1021.87	0.0003		0.703
				0.651	603.33	0.8996; (0.873)		0.107
	671.89	0.6769; (0.789)		0.155				0.255
				0.609				0.654
	596.37	0.0011		0.705	590.06	0.1679		0.658
CAM-B3LYP	566.25	1.1978; (0.936)		0.698	535.76	1.2807; (0.947)		0.696
	498.61	0.0016		0.682	503.49	0.0084		0.689
				0.139	352.1	0.0017		0.652
	396.76	0.0499		0.657				0.192
				0.172
PEB1PBE	599.656	0.221		0.610	600.44	0.0065		0.699
			118-119	0.341	546.28	1.2519; (0.944)		0.707
	590.685	0.791; (0.838)	118-119	0.620	402.93	0.0003		0.504
	461.941	0.133	116–119	0.682				0.184
			118–120	0.103

In SQ1, the number of HOMO is 118. In SQ2, the number of HOMO is 105.