Thin-film electrocaloric and pyroelectric sources for electrothermal energy interconversion have recently emerged as viable means for primary and auxiliary solid-state cooling and power generation. Two significant advances have facilitated this development: (1) the formation of high-quality polymeric and ceramic thin films with figures of merit that project system-level performance as a large percentage of Carnot efficiency and (2) the ability of these newer materials to support larger electric fields, thereby permitting operation at higher voltages. This makes the power electronic architectures more favorable for thermal to electric energy interconversion. Current research targets to adequately address commercial device needs including reduction of parasitic losses, increases in mechanical robustness, and the ability to form nearly freestanding elements with thicknesses in the range of 1–10 μm. This article describes the current state-of-the-art materials, thermodynamic cycles, and device losses and points toward potential lines of research that would lead to substantially better figures of merit for electrothermal energy interconversion.

Both ZnO and PZT Thin Film Bulk Acoustic Resonator filters were fabricated, tested and modeled in this study. The development of an accurate Mason model allows the effect of particular parasitic components on the microwave s-parameters in the region of the series and parallel resonances to be identified. The parasitic components that limit the performance of our ZnO and PbZr0.3Ti0.7O3 Thin Film Bulk Acoustic Resonator filters are analysed. From an analysis of PbZr0.3Ti0.7O3 Thin Film Bulk Acoustic Resonator measurements values for the longitudinal acoustic velocity and electromechanical coupling coefficient can be derived. Measured PbZr0.3Ti0.7O3 Thin Film Bulk Acoustic Resonator filter responses confirm that the larger electromechanical coupling coefficients in this material compared to ZnO give wider filter band-widths.

The thin film growth of PbTiO3 by MOCVD has been investigated using both a pyrolytic process and a sputter assisted plasma deposition process. In the first process, lead tertiary butoxide and titanium iso-propoxide are introduced to a low pressure reactor simultaneously to deposit thin films containing lead and titanium onto a hot substrate (400–500 °C). In the alternative process lead is sputtered from a magnetron target in the presence of titanium isopropoxide vapour. Thin films containing lead and titanium are deposited onto a substrate which need not be heated. X-ray and EDAX analysis indicate the presence of Ti02 and elemental lead in the as grown layers. Oxygen annealing of ihese layers at 900° and 1100°C leads to the formation of polycrystalline PbTiO3 and where the substrate is silicon, a PbO/SiO2 glass phase.