Tunable band gap of iron-doped lanthanum-modified bismuth titanate synthesized by using the thermal decomposition of a secondary phase

Abstract

The photoelectric properties of complex oxides have prompted interest in materials with a tunable band gap, because the absorption The substitution of iron atoms in La-modified bismuth titanate (BLT) can lead to dramatic improvements in the band gap, however, the substitution of iron atoms in BLT without forming a BiFeO 3 secondary phase is quite challenging. Therefore, a series of Fe-doped BLT (Fe-BLT) samples were characterized using a solid reaction at various calcination temperatures (300~900°C) to remove the secondary phase. The structural and optical properties were analyzed by X-ray diffraction and ultraviolet-visible absorption spectroscopy. This paper reports a new route to synthesize a pure Fe-BLT phase with a reduced optical band gap by high temperature calcination due to the thermal decomposition of BiFeO 3 during high temperature calcination. This simple route to reduce the second phase can be adapted to other complex oxides for use in emerging oxide optoelectronic devices.

Octahedral distortion and oxygen vacancies induced band-gap narrowing and enhanced visible light absorption of Co/Fe co-doped Bi3.25Nd0.75Ti3O12 ferroelectrics for photovoltaic applications

“…Consequently, it became necessary to reduce its bandgap maintaining its ferroelectric response for visible light PV applications [11]. Physical properties of the Bi 4 Ti 3 O 12 compound can be controlled either by single doping at Bi or Ti site [13][14][15][16][17][18] or by co-doping on both sites simultaneously [19][20][21][22]. H Zhang et al [23], based on band structure theory, reported that Cr 3+ ions doping on the Ti 4+ site of BiT does not affect the position of the valance band edge, but new energy levels were formed within the bandgap resulting in photocatalytic activity in the energy range of the visible light.…”

The Effects of Lanthanum Dopant on the Structural and Optical Properties of Ferroelectric Thin Films

“…The other work by Han et al shows that La-modified bismuth titanate (BLT) can also be doped further by iron atoms, leading to large improvements in the bandgap property even though challenges still exist due to the difficulty in creating BLT without forming a BiFeO 3 secondary phase [7]. To remove the secondary phase, Han et al performed a solid reaction at various calcination temperatures (300-900°C).…”

Low temperature magnetic behavior and thermal expansion anomaly of cubic CeTiO3

“…Lanthanum LnBO 3 -based perovskite oxides have demonstrated fascinating performances in ionic conductivity, 1 photoelectricity, 2 catalysis, 3 ferroelectric and magnetism. 4,5 By adjusting the chemical composition appropriately, the crystal structure together with charge and electronic structure can be facilely manipulated, which triggers the lattice distortions of BO 6 -octahedra and engineers the unusual physical properties.…”