Enhancement of photoelectrochemical performance in ferroelectric films via the introduction of an Au buffer layer

The inefficient separation of photogenerated carriers has become a serious problem that limits the photoelectrochemical (PEC) performance of semiconductors. Herein, a sol-gel method was used to prepare BiFeO3 ferroelectric thin films with FTO and FTO/Au as substrates, respectively. The polarization electric field of the ferroelectric can more effectively separate the carriers generated in the photoelectrode. Meanwhile, the introduction of an Au buffer layer can reduce the resistance in the process of charge transfer, accelerate the carrier migration, and enhance the efficiency of the charge separation. Under light irradiation, Au/BiFeO3 photoelectrode exhibited an extraordinary improvement in PEC water splitting compared with BiFeO3. In addition, the ferroelectric polarization electric field causes band bending, which further accelerates the separation of electrons and holes and improves the PEC performance of the photoelectrode. This work promotes the effective application of ferroelectric films in PEC water splitting.

Effect of Structural Deficiencies on Bi-Ferroic Behaviors of Lead-Free Bi0.5 Na0.40K0.10TiO3 Films

Lead-free Bi0.5Na0.4K0.1TiO3 (BNKT) ferroelectric films on Pt/TI/SIO2/Si substrates were prepared via a sol-gel spin coating routine. The microstructures and multiferroic behaviors of the films were examined intimately as a function of the annealing time. A rise of annealing time enhanced the crystallization of the films via the perovskite structure. The multiferroic behavior, including simultaneously the magnetic and ferroelectric orders, was observed altogether the films. When the annealing time rose, ferroelectric and magnetic properties were found significantly increased. The remnant polarization (Pr), also as maximum polarization (Pm) respectively increased to the very best values of 11.5 µC/cm2 and 40.0 µC/cm2 under an applied electric field of 500 kV/cm. The saturated magnetization (Ms) of films increased to 2.3 emu/cm3 for the annealing time of 60 minutes. Oxygen vacancies, originating from the evaporation of metal ions during annealing at high temperatures are attributed to the explanation for ferromagnetism within the BNKT films.

Enhanced Tunability of BaTixSn1−xO3 Films on Dielectric Substrate

The structural properties of ferroelectric films of barium titanate-stannate on alumina substrates and the microwave characteristics of planar capacitive elements based on them are studied. It is established that the composition of the gas medium and the temperature of the substrate during the deposition of the film has a significant effect on the crystal structure, phase composition of the films and their electrical characteristics. Planar capacitors based on films subjected to high-temperature annealing after deposition exhibit 85% tunability at a frequency of 2 GHz, which is the best result for today.