Optical Properties on the Ferroelectric Perovskite Materials: a Study for Photovoltaic Applications

Ferroelectric and multiferroic magnetoelectric materials Pb(ZrxTi1-x)O3, BiFeO3–PbTiO3, BiFeO3 PbTiO3, and PbZrO3 with perovskite structure were synthetized, and their optical and structural properties were investigated aiming photovoltaic applications. Single-phase structural properties were observed on the Pb(ZrxTi1-x)O3 and BiFeO3–PbTiO3 systems in their respective regions on phase diagram. Alternative photoacoustic spectroscopy was used to investigate optical properties of the compounds in powder state. Intense absorption was observed in the photoacoustic signal on the visible region of the electromagnetic spectrum. Interesting energy gap was observed in the BiFeO3 (Eg = 1.50 eV) and BiFeO3–PbTiO3 (Eg = 1.53 eV), which are remarkably close to the optimized value (Eg = 1.32 eV) to maximize the photovoltaic efficiency of the theory Shockley-Queisser. The physical mechanisms that distort the structure promote ferroelectricity and remodel the structures of energy bands have been pointed out and discussed.