Table 1.

Band gaps of the pristine Bi₄Ti₃O₁₂ and various Bi₄Ti₃O_12−x samples.

Samples	Band Gap (eV)
Bi4Ti3O12	2.91
Bi4Ti3O12−x (350 °C, 20 min)	2.83
Bi4Ti3O12−x (350 °C, 40 min)	2.74
Bi4Ti3O12−x (350 °C, 60 min)	2.63
Bi4Ti3O12−x (350 °C, 80 min)	2.57
Bi4Ti3O12−x (350 °C, 100 min)	2.48
Bi4Ti3O12−x (300 °C, 60 min)	2.77
Bi4Ti3O12−x (400 °C, 60 min)	2.39