Research Article
DFT Study of Polythiophene Energy Band Gap and Substitution
Effects
Table 4
Excitation energy values
for the studied compounds obtained by TD-DFT/CAM-B3LYP, TD-DFT/ B3LYP with 6-31G (d,p) level.
| | Compounds | (nm) Exp [26] | TD-B3LYP | TD-CAM-B3LYP (DMSO) | TD-CAM-B3LYP | | (nm) | (eV) (OS) | (nm) | (eV) (OS) | (nm) | (eV) (OS) | Molecular orbital |
| | 8T | 448 | 644.59 | 1.92 (2.9063) | 493.62 | 2.51 (3.0912) | 478.07 | 2.59 (2.9578) | HL (0.63)
| | 553.29 | 2.24 (0.000) | 410.15 | 3.02 (0.000) | 392.33 | 3.10 (0.0000) | | 536.39 | 2.31 (0.000) | 323.15 | 3.83 (0.000) | 323.00 | 3.83 (0.0000) |
| | 8TOC | | | | | | | | | | HT | | 717.23 | 1.72 (1.4020) | 545.14 | 2.27 (3.2032) | 529.71 | 2.34 (2.9449) | HL (0.64) | | | 557.36 | 2.22 (1.6056) | 437.88 | 2.83 (0.0002) | 420.71 | 2.94 (0.0021) | | | 514.85 | 2.40 (0.0072) | 365.82 | 3.38 (0.2814) | 364.69 | 3.39 (0.2123) | | HH | | 661.72 | 1.87 (2.8471) | 568.23 | 2.18 (3.1391) | 544.55 | 2.27 (3.0037) | HL (0.64) | | 465 | 551.55 | 2.24 (0.000) | 453.48 | 2.73 (0.000) | 430.04 | 2.88 (0.000) | | | 452.97 | 2.73 (0.000) | 362.33 | 3.42 (0.000) | 360.74 | 3.43 (0.000) | | TT | | 646.58 | 1.91 (2.8253) | 555.33 | 2.23 (3.0750) | 533.32 | 2.32 (2.9676) | HL (0.64)
| | | 537.95 | 2.30 (0.000) | 442.30 | 2.80 (0.0041) | 421.18 | 2.94 (0.0035) | | | 475.32 | 2.60 (0.000) | 355.93 | 3.48 (0.0004) | 354.62 | 3.49 (0.0001) |
| | 8TCOC | | | | | | | | | | HT | | 529.52 | 2.34 (2.4562) | 450.23 | 2.75 (2.5260) | 439.61 | 2.82 (2.8030) | HL (0.62)
| | 445.36 | 2.78 (0.0966) | 381.34 | 3.25 (0.0568) | 368.61 | 3.36 (0.0488) | | 422.03 | 2.93 (0.0397) | 331.52 | 3.73 (0.3015) | 322.30 | 3.84 (0.2428) | | HH | | 472.08 | 2.62 (2.1440) | 404.35 | 3.06 (2.6989) | 396.18 | 3.12 (2.5865) | HL (0.62)
| | — | 408.34 | 3.03 (0.0008) | 356.82 | 3.47 (0.0998) | 346.23 | 3.58 (0.0852) | | 396.27 | 3.12 (0.0661) | 319.08 | 3.88 (0.2093) | 285.81 | 4.33 (0.0000) | | TT | | 467.12 | 2.65 (2.0300) | 411.63 | 3.01 (2.7553) | 392.82 | 3.15 (2.4701) | HL (0.62)
| | | 403.97 | 3.06 (0.0042) | 361.59 | 3.42 (0.0509) | 341.87 | 3.62 (0.0641) | | | 398.18 | 3.11 (0.0434) | 324.29 | 3.82 (0.3900) | 313.40 | 3.95 (0.4098) |
| | 8TOOC | — | 573.29 | 2.16 (2.6859) | 489,34 | 2.53 (3.0704) | 474.22 | 2.61 (2.9274) | HL (0.64) | | 479.95 | 2.58 (0.000) | 408.35 | 3.05 (0.000) | 392.48 | 3.15 (0.0001) | | 445.88 | 2.78 (0.000) | 348.35 | 3.55 (0.2826) | 337.04 | 3.67 (0.2340) |
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