Light-Annealed Piezoelectric Films on Flexible Glass

The functionalization of thin, flexible glass with piezoelectric oxides is a pathway toward transparent electromechanical devices. The crystallization of lead zirconate titanate thin films on thick, rigid glass is previously demonstrated using flash lamp annealing to selectively anneal the films, without damaging the substrates. In this work, a 2-step process suitable for Schott AF 32 eco glass and Corning Willow glass is developed, both 100 μm thick, the latter of which is compatible with roll-to-roll processes. Herein, demonstration is done of: 1) the importance of heat management during flash lamp annealing; and 2) a method to orient perovskite thin films during their crystallization by flash lamp annealing. With this process, the 540 nm thick lead zirconate titanate thin films with morphotropic phase boundary composition display a relative permittivity ε _r of 330, a dielectric loss of 8.4% and a piezoelectric coefficient $e_{33\text{,f}}$ of 5.5 C m^-2. This work demonstrates the feasibility of transparent piezoelectric films, which has a potential to opening the way to flexible and invisible devices.