Aging Characteristics of a Hybrid Sol-gel Pb(Zr, Ti)O3 Precursor Solution

Abstract
The “aging” characteristics of an acetic acid/methanol solvent-based lead zirconate titanate (PZT) precursor solution, prepared by the Inverted Mixing Order (IMO) process, have been studied for an extended period of time. The changes in film properties were characterized using optical microscopy, optical scattering, and ferroelectric testing. Films generated from the IMO process exhibit an increase in thickness as a function of solution age due to chemical “aging” (esterification) of the precursor solution. This increased thickness results in a decrease in the microstructural uniformity, which affects the electrical and optical properties. In order to understand and eventually control this phenomenon, we have quantified the “aging” of this solution using a variety of analytical methods, including 1H NMR spectroscopy, pH measurements, and Fourier transform infrared (FTIR) spectroscopy. It is of note that we have discovered a method that circumvents this “aging” problem by removal of the volatile material, forming an IMO powder which can be redissolved to produce high quality PZT thin films whenever desired.