Table 2. Size and Band Gap Energy.
| crystal and particle
sizes (nm) |
band gap energy
(eV) |
||||||
|---|---|---|---|---|---|---|---|
| material | d(Bohr) (nm) | X | d(XRD) | d(BET) | d(UV–vis) | calculated | measured |
| TiO2 | 2 | 1 | 5.8 | 5.5 | 2.1 | 3.2 | 3.4 |
| 0.8 | 3.3 | 5.5 | 2.1 | 3.3 | 3.4 | ||
| 0.7 | 2.3 | 5.6 | 1.7 | 3.4 | 3.5 | ||
| 0.1 | 9.0 | 0.9 | 4.3 | ||||
| ZnO | 2.34 | 1 | 28.6 | 42.0 | bulk | 3.2 | 3.2 |
| 0.8 | 7.1 | 8.2 | 3.4 | ||||
| 0.7 | 7.8 | 6.9 | 3.4 | ||||
| 0.3 | 4.8 | 4.3 | 3.7 | ||||
| 0.1 | 4.2 | 2.1 | 5.4 | ||||
| SnO2 | 5.4 | 1 | 4.8 | 5.4 | 5.2 | 3.8 | 3.8 |
| 0.7 | 4.7 | 4.0 | 3.9 | ||||
| 0.5 | 4.9 | 3.7 | 4.0 | ||||
| 0.3 | 4.9 | 3.0 | 4.2 | ||||
| 0.2 | 5.6 | 2.7 | 4.3 | ||||
| 0.1 | 6.4 | 2.2 | 4.7 | ||||
| CuO | 7 | 1 | 7.4 | 8.9 | 4.5 | 1.6 | 1.7 |
| 0.9 | 7.8 | 3.3 | 1.9 | ||||
| 0.7 | 5.5 | 1.8 | 2.7 | ||||
| 0.5 | 5.5 | 1.7 | 2.9 | ||||
| 0.3 | 6.1 | 1.6 | 3.0 | ||||
| 0.2 | 9.6 | 1.6 | 3.0 | ||||
| 0.1 | 10.3 | 1.4 | 3.5 | ||||
| 0.05 | 14.3 | 1.4 | 3.7 | ||||