Modified structure and optical band-gap in perovskite ferroelectric (1-x)KNbO3-xBaCo1/3Nb2/3O3 ceramics

In the process of exploring ideal ferroelectric perovskites for photovoltaic applications, a novel kind of ceramic (1- x )KNbO 3 - x BaCo 1/3 Nb 2/3 O 3 ( x KBCNO) has been synthesized using solid-state method. The phase transition, microstructure, optical and ferroelectric properties of the compounds were investigated in detail. X-ray diffraction and Raman scattering spectra analyses indicate that single phase ceramics have been formed with cubic perovskite structure in space group Pm 3 m . Obvious crystal lattice expansion can be found as x increases. A narrow band gap of 1.87 eV is observed at x  = 0.75, which proves the dramatic effect of BaCo 1/3 Nb 2/3 O 3 (BCNO) addition on the energy band gap . Besides, the room-temperature ferroelectricity has been detected in KBCNO ceramics controlled by the BCNO doping content. These results lay a solid foundation on further exploring the phase transition, band gap engineering, and electric properties in perovskite oxides , and indicate potential applications in perovskite solar cells .