Size effect of PbTiO3 on its charge separation ability

PbTiO3 (PTO) is a ferroelectric oxide with a typical ABO3-type perovskite structure. However, the majority of prior research has concentrated on the PTO material preparation process, making the correlation between heteroatom doping and the piezoelectric effect superior. It is also worthwhile to pay attention to its internal mechanism and the size effect of the redesigned interface, which will result in many fresh experimental occurrences. In this work, first-principles methods were used to investigate the crystal geometry, electronic structure, electrical characteristic, and surface charge transfer of monolayer as well as multilayer PTO in order to understand the origin of significant size effect. Only the 1̅10 crystal plane has a considerable size effect in contrast to other crystal planes, and its energy gap is correlated with the thickness of its layers, according to our research. The energy gap consistently shrinks as size and thickness grow. The findings demonstrate that PTO can change from a semiconductor to a metal due to the size effect. And the increase in the dielectric silica coating can promote the separation of surface charge by enhancing the polarization characteristics of the exposed oxygen atom of PTO. Our research not only clarifies the process of charge separation brought on by the different PTO size, but it also offers a suggestion for investigating the interfacial interactions of more ABO3-type perovskite-structured semiconductor materials.