טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentArsen Gevorkyan
SubjectElectrospinning of Piezoelectric (PZT)
Ceramic Nano Fibers for Energy Harvesting
DepartmentDepartment of Energy
Supervisors Full Professors Grader Gideon
Dr. Shter Gennady
Full Thesis textFull thesis text - English Version


Abstract

The special properties of piezoelectric ceramics made them a material of choice for wide variety of applications like sensors, actuators, transducers, etc. Recently these materials are intensively investigated for energy harvesting applications. A promising way for scavenging energy from the environment is based on their ability to develop electrical charge in proportion to a mechanical stress. PZT [Pb(TixZr1-x)O3] is piezo- and pyroelectric material with a very high piezoelectric coefficient and dielectric constants, making it most suitable for conversion of mechanical energy to electrical power. In order to use PZT in microelectronics and other applications its dimensions should be reduced to micro or nano scales. There are two possible PZT forms for micro devices: fibers (1D structure) and thin films (2D structure). Fibers allow more flexibility in devices design and can be used as functional fillers for composite materials. To ensure a large degree of fiber bending it is critical to control the uniformity, length and diameter of the fibers in the submicron range.

One of the promising ways for nano fibers fabrication is electrospinning (ES) based on the injection of colloidal solution (PZT precursor) into strong electrostatic field. ES is a simple and flexible process which facilitates the production of polymer, ceramic, composite and metal fibers with desired dimensions and properties.

The current study used electrospinning for preparation of ceramic PZT nanofibers with an emphasis on dimensions, thermal treatment, phase composition, deposition control and in situ thermal treatment. An attempt was made to prepare separated fibers rather than random mats by conducting electrospinning in hot environment to prevent formation of joints at points where the nanofibers overlap. Thermal treatment procedure was developed according to the TGA/DTA/MS studies. Based on the results it was proposed to use an initial prefiring step to burn out most of the organics followed by a phase formation step at higher temperatures using either long sintering procedure either rapid thermal processing (RTP). The research led to the submission of two publications: first on the fiber diameter and morphology control, and the second on the RTP process.