Thin Film Coating with Highly Dispersible Barium Titanate-Polyvinylpyrrolidone Nanoparticles.

Jinhui Li,Akihiro Tsuruta,Koji Inukai,Woosuck Shin,Yosuke Takahashi

doi:10.3390/ma11050712

Abstract

Thin BaTiO3 (BT) coating layers are required in various multilayer ceramic technologies, and fine nanosized BT particles with good dispersion in solution are essential for this coating process. In this work, cubic and tetragonal phase monodispersed BT nanoparticles—which were referred to as LBT and HBT-PVP coated on their surface by polyvinylpyrrolidone (PVP) polymer—were prepared by low temperature synthesis (LTS) and hydrothermal method (HT) at 80 and 230 °C, respectively. They were applied for the thin film coating on polyethylene terephthalate (PET) and Si wafer substrates by a simple bar coating. The thickness of BT, LBT-PVP, and HBT-PVP films prepared by their 5 wt % coating agent on Si are around 268, 308, and 263 nm, and their surface roughness are 104.6, 91.6, and 56.1 nm, respectively. The optical transmittance of BT, LBT-PVP, and HBT-PVP films on PET are 55, 66, and 73% at 550 nm wavelength and the haze values are 34.89, 24.70, and 20.53% respectively. The mechanism of dispersant adsorbed on the BT surface for densification of thin film during the drying process of the film was discussed.

Highlights

BaTiO3 (BT) is widely used in multilayer ceramic capacitors, semiconductors, positive temperature coefficient thermistors, and piezoelectric devices [1,2] owing to its ferroelectric [3,4] and piezoelectric [5,6,7] properties
The crystalline phases of commercial BT and LBT-PVP prepared by low temperature synthesis (LTS) process are cubic, and that of HBT-PVP prepared by hydrothermal method (HT) process is tetragonal as reported in our previous paper [21,22]
Monodispersed cubic and tetragonal BaTiO3 (BT) particles coated on its surface by PVP polymer was synthesized by low temperature directly synthesis and hydrothermal method respectively, and was applied for the thin film coating on polyethylene terephthalate (PET) and Si wafer substrates by a simple bar coating and drying process

Summary

Introduction

BaTiO3 (BT) is widely used in multilayer ceramic capacitors, semiconductors, positive temperature coefficient thermistors, and piezoelectric devices [1,2] owing to its ferroelectric [3,4] and piezoelectric [5,6,7] properties. Many processing methods for ferroelectric, high refractive index thin films have been developed for this purpose, such as chemical solution deposition by the sol–gel process [13] or physical depositions by sputtering [14], pulsed laser ablation [15], and chemical vapor deposition [16]. Each of these processes has advantages and disadvantages. The sol–gel coating method is the most popular process to obtain large-area thin films with good homogeneity and smooth surface at low temperatures. In the sol–gel process, films are deposited by dip coating [17,18] and spin coating [19,20], followed by high-temperature treatment

Methods

Results

Conclusion