Role Of Piezoelectric Effects Research Articles

Adsorption and activation of peroxymonosulfate on BiOCl for carbamazepine degradation: The role of piezoelectric effect

The adsorption of peroxymonosulfate (PMS) is crucial for PMS activation in the heterogeneous advanced oxidation processes. However, the investigation of PMS adsorption on the piezocatalysts still remains insufficient. In this work, bismuth oxychloride (BiOCl) nanosheets were prepared as the piezocatalysts for PMS activation under ultrasonic vibration to remove carbamazepine (CBZ) in aqueous solutions. Up to 92.5% of CBZ was degraded for 40 min in BiOCl piezo-activated PMS system with the reaction rate constant of 0.0741 min−1, being 1.63 times that of the sum of BiOCl piezocatalysis, BiOCl-activated PMS, and vibration-activated PMS. PMS adsorption on the surface of BiOCl was specifically studied by comparing the microscopic structure change of the fresh and used BiOCl. The results suggested that the piezoelectric field of BiOCl was able to promote the tight adsorption of PMS on the surface, thus facilitating the fast activation of PMS through electrons transfer to produce reactive species (HO•, SO4•−, O2•−, 1O2). This work presents an in-depth understanding for the role of piezoelectric effect on the adsorption and activation of PMS.

Single layer In-O atomic sheets as phonon and electron barriers in ZnO-In2O3 natural superlattices: Implications for thermoelectricity

The phases in the ZnO half of the ZnO-In2O3 binary system are natural superlattices consisting of a periodic stacking of single InO2 sheets separated by indium doped ZnO blocks with a spacing that depends on the composition according to the relationship In2O3(ZnO)k. Characterization by combined, atomic resolution, aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy analysis indicates that the atomic structure of each InO2 layer consists of a single continuous sheet of octahedrally coordinated InO2. The sheets are also crystallographic inversion boundaries. Analysis of the electrical conductivity, thermal conductivity, and Seebeck coefficient data at 800 °C indicates that the InO2 sheets not only decrease thermal conductivity by phonon scattering but also create potential barriers to electron transport. The origin of the potential barriers, the role of piezoelectric effects, and their dependence on superlattice spacing are discussed qualitatively. It is also argued that the crystallographically aligned InO2 sheets within individual grains are also transport barriers in randomly oriented polycrystalline materials.

Analytical Study on Piezoelectric Effects on Exciton Dissociation

AbstractWe analytically and numerically compute the Onsager dissociation rate (exciton dissociation) on an interface induced by a piezoelectric potential in an inorganicorganic hybrid p-n junction system (ZnO + (poly(p-phenylene vinylene)); PPV). When a positive piezoelectric potential is created at the interface region owing to the deformation of the system, free electrons accumulate at the interface. Hence, screening effects are observed. It is assumed that the electron layer formed at the interface then attracts free holes from the p-type PPV region, which leads to exciton formation, possibly via the Langevin recombination process. The increased exciton density can then contribute to the Onsager dissociation rate, which is maximum around the interface. This paper focuses on the role of piezoelectric effects in promoting exciton formation at the interface and its relation with the exciton dissociation rate.