The Fabrication And Application Of Ferroelectric Polymer P(VDF-TrFE) With Nanostructure

Polymer has a large of advantages such as low cost, easy processing, good flexibility, so it becomes a hotspot in the research of materials. Polyvinylidene fluoride(PVDF) and its copolymer as a representative of ferroelectric polymer materials, has not only the commonness of polymer, and also has a series of unique performance, such as ferroelectric, piezoelectric and pyroelectric property. These features make ferroelectric polymer materials have a broad application prospects in ferroelectric information storage, pressure sensors, infrared detector, solar cells, and other fields. For PVDF and its copolymers, its ferroelectric is the result of the dipole orientational which is made up with H-F atom pairs. So the orientation of molecular chain and dipole will have profound effects on the performance of the material. Therefore, the researchers studied a series of methods to obtain molecular chain structure with specific orientation such as limited space orientation, tensile orientation, electric field orientation and so on. The crystal which has a specific orientation get huge promotion on some physical properties, and provides the possible to get organic functional device with excellent performance.In this paper, we choose P(VDF- TrFE) as the research object because it has a more stable ? phase structure relative to the PVDF, which means that P(VDF- TrFE) has more reliable ferroelectricity. Our team have studies the relationship between performance and orientation of P(VDF- TrFE) in confined space before. On this foundation, we use porous anodic aluminum oxide(AAO) as a template to build different diameters of P(VDF-TrFE) nanopillars by nanoimprint lithography, Through the PFM tests we found that the patterned structure has better piezoelectric response and smaller coercive field relative to the thin film. What’s more, the coercive field will be smaller with the decrease of the diameter of nanopillars. Then this nanopillar array structure is applied to the polymer solar cells with P3HT: PCBM blend system. As a result, we find that the efficiency of solar cells with positive poled P(VDF-TrFE) is much more better than the negative poled one.In addition of the application in solar cells, P(VDF- TrFE) also has been widely used in transducer as its perfect piezoelectricity. In this article, we use porous polyimide film as substrate, constructed the continuous P(VDF- TrFE) nanowires in polyimide pipeline by the method of melt filled. Then we study the piezoelectric response of nanowires under pressure. We find that P(VDF-TrFE) nanowires have a more strong piezoelectric response signal then thin film. By grazing incidence X-ray diffraction(GIXD), we analyzed the wafer orientation of nanowires and thin film. We find that the molecular chain of Nanowires along the direction perpendicular to the pipe and the molecular chain of film along the direction perpendicular to the substrat at the same time. In addition, we calculated the piezoelectric voltage constant of nanowires according to the relationship between the voltage response pressureand and find it’s much higher than the value of thin film.In conclusion, we construct the ferroelectric polymer P(VDF- TrFE) nanostructures through a series of methods. And we study the influence of P(VDF-TrFE) nanostructures in ferroelectric polymer solar cell and piezoelectric. The main significance of this thesis is to further research the relationship between the polymer performance and confinement On the basis of previous work. And the paper provide a reference value in practical device applications of ferroelectric polymer nanostructures.