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Enhancement of the Electrical Performance of the Organic Ferroelectric Memory Transistor by Reducing the Surface Roughness of the Polymer Insulator with a Homo-Bilayer PVDF-TrFE
摘要： We suggest a feasible method to enhance the electrical performance of the organic nonvolatile memory transistor by reducing the surface roughness of the ferroelectric polymer insulator. A homo-bilayer of poly(vinylidene?uoride-co-tri?uoroethylene) [P(VDF-TrFE)] was used to control the high surface roughness of the conventional single layer [P(VDF-TrFE)] polymer insulator. The smoothening of the polymer insulator was achieved as the Z rms roughness was as low as 11.9 nm compared to the aboriginal single P(VDF-TrFE) ?lm of 18.8 nm. The homo-bilayer P(VDF-TrFE) thin ?lm transistor showed a higher memory on-off ratio (about 100) and mobility (2.9 × 10?2 cm2v?1s?1) compared with the native P(VDF-TrFE) with memory on-off ratio of 16 and mobility of 2.1 × 10?2 cm2v?1s?1. The underlying mechanism for the mobility enhancement which resulted in a high on-off ratio is mainly attributed to the reduction of the surface roughness of the ferroelectric polymer insulator.
关键词： Organic Thin Film Transistor,Ferroelectric,Homobilayer,P(VDF-TrFE)
更新于2025-09-04 15:30:14
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Análise da expans?o térmica volumétrica e das características estruturais de solu??es sólidas de (Pb, Ca)TiO3 entre 150 e 570 K
摘要： Ceramic samples of lead modified calcium titanate (Pb1-xCaxTiO3) with calcium concentration between 0.24≤x≤0.55 were prepared and analyzed in order to determine the structural origin of the negative thermal expansion observed in this ferroelectric system. The Rietveld structural refinement method was used to assess the thermal evolution of the structural parameters using powder X-ray diffraction data collected between 150 and 570 K. Since the Pb1-xCaxTiO3 phase diagram and space groups are still unknown for the temperature range investigated, the structural analyses were based on adjustments of the refinement protocol. The results revealed the existence of a correlation between symmetry transitions and anomalies in the thermal expansion of the unit cell, being such transitions not necessarily of the ferroelectric-paraelectric nature.
关键词： Rietveld refinement method,symmetry transitions,structural analyses,unit cell thermal expansion,ferroelectric ceramics
更新于2025-09-04 15:30:14
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Selective Ferroelectric BiOI/Bi4Ti3O12 Heterostructures For Visible-light-driven Photocatalysis
摘要： Ferroelectric-photocatalyst/photocatalyst heterojunctions have very attractive photocatalytic activities. Beside enhanced charge carrier separation due to their internal electric fields, charge transfer could be even further enhanced by designing the heterojunction interface. In this work, the polarization-adsorption interaction that exists in ferroelectric materials was employed for successful deposition of BiOI on specific surfaces of Bi4Ti3O12 plates in the dark at room temperature, where the positively polarized region was found. The crystal structure, morphology, and composition of samples were confirmed by X-ray diffraction, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy, respectively. Higher photocatalytic activity was achieved by the use of heterojunctions, with the reason behind the enhancement of activity confirmed to be the modified band structure, which contributed to the transfer of photoelectrons from Bi4Ti3O12 to BiOI, the increased visible light absorption, the increased active site area of positively polarized Bi4Ti3O12, and the elimination of the screening layer, which contributes impedance in charge transfer.
关键词： Visible-light-driven,Photocatalysis,Heterostructures,BiOI/Bi4Ti3O12,Ferroelectric
更新于2025-09-04 15:30:14