Structural phase transition, narrow band gap, and room-temperature ferromagnetism in [KNbO3]1−x[BaNi1/2Nb1/2O3−δ]x ferroelectrics

Investigation of microstructural and optical properties of (K,Ba)(Ni,Nb)O3−δ thin films fabricated by pulsed laser deposition

“…These oxides exhibit both ferroelectricity and a wide variation of bandgaps in the range of 1.1-3.8 eV, which will be the most promising candidate as visible-light-absorber for solar cells. Similar results have also been reported in our previous works [11], and the synthesized ferroelectric ceramics have a narrow E g of below 1.5 eV matching the solar spectrum, which creates opportunities for innovation in PV cells and state of the art optoelectronic devices. As we all know, compared with bulk materials, thin films occupy more important position in the field of actual device preparations.…”

“…2 shows the XRD pattern of the KBNNO film to be consistent with a single-phase perovskite structure, at least within the detection limits of the instrument, and no impurity phases are observed, as compared with the standard peaks taken from JCPDS (71-0945). In our previous experimental results [11], KNbO 3 ceramics has been shown to be an orthorhombic (Amm2) perovskite, and the different peak shapes were involved as the composition changes, where Bragg reflections for KBNNO ceramics are fully indexed as cubic perovskites. This indicated a structural transition from orthorhombic to cubic.…”

Magnetism switching and band-gap narrowing in Ni-doped PbTiO3 thin films

“…10,17 This band-gap narrowing effect is due to new states in the electronic structure of both the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) associated with the presence of Ni stabilized by an accompanying O-vacancy ( Fig. 5(b)).…”

“…14 However, these ferroelectric oxides (e.g., PTO, BaTiO 3 , etc.) have wide band-gap (E g ) of above 3.0 eV, 10,15 absorbing light primarily in the ultraviolet region. This has become a major obstacle that limits their photovoltaic applications.…”

Modified structure and optical properties of multiferroic Pb(Zr0.53Ti0.47)x(Fe0.5Nb0.5)(1−x)O3 ceramics

“…It is apparent that the band gap absorption edges of the samples exhibit a blue-shift with the x increasing. The corresponding optical band gaps of xPZTFN can be estimated from the tangent lines in the plot of the Kubelka-Munk function (αhν) 2 versus hν for the direct band gap material, where α is absorbance and hν is photon energy [25], as presented in Fig. 5 gap of PZT is also shown to be 3.21 eV.…”