Figure 3

Optical properties of the BLT, BLCT and BLFCT films.
(a) The transmittance data depending on the wavelength (200–800 nm) for BLT, BLCT and BLFCT on the STO (001) substrates. (b) The bandgap energy was estimated by extrapolating the linear part of the (αhν)2 versus energy plots for BLCT and BLFCT on STO. The inset shows absorbance as a function of energy for BLCT and BLFCT on STO.