Fabrication of PbTiO3/PVDF-TrFE organic thin film capacitors / Nurbaya Zainal

• Main Author: Zainal, Nurbaya
• Format: Thesis
• Language: English
• Published: 2019
• Subjects: Dielectrics; Electric conductivity
• Online Access: https://ir.uitm.edu.my/id/eprint/62937/1/62937.pdf; https://ir.uitm.edu.my/id/eprint/62937/

This study presents a new dielectric material utilized for thin film organic capacitors. It consists of a combination of organic and inorganic ferroelectric materials, namely lead titanate (PbTiO3) and polyvinylidene fluoride trifiuoroethylene (PVDF-TrFE). In most ceramic-polymer dielectric films, the combination of PbTiO3 and PVDF-TrFE as a form of bilayer configuration has never been explored. The study highlights that with a presence of PVDF-TrFE as a second layer, the dielectric and ferroelectric property of PbTiO3 thin film improved. In this study, the dielectric thin films were prepared using a simple and cost-effective method of sol-gel spin coating. The deposition parameters for the synthesized PbTiO3 thin film was optimized at 0.4 M solution concentration, 10 wt% of excess Pb content, and annealed at 550°C. Subsequently, the optimized PbTiO3 thin film was utilized as a novel bilayer structure of PbTiO3/PVDF-TrFE film. The film demonstrated high dielectric permittivity value (εr~ 217)*and low tangent loss (tan (δ) ≈ 0.0017). In addition, the film has showed tremendous enhancement of remnant polarisation (Pr = 18.66 ^C/cm2 ), which is three times higher than a single PbTiO3 thin film. The new approach of parallel capacitor design is the highlight of this study and managed to produce high capacitance value (C ≈ 13.4 nF/cm2 ). To date, this is a notable achievement of the dielectric and ferroelectric properties for bilayer dielectric film as none of this finding has been declared, so far. Hence, a novel bilayer structure of PbTiO3/PVDF-TrFE film can be a promising candidate for high capacitance thin film capacitors.