Novel ZnO nanorod films by chemical solution deposition for planar device applications.

Smooth and continuous ZnO films consisting of densely packed ZnO nanorods (NRs), which can be used for electronic device fabrication, were synthesized using a hydro-thermo-chemical solution deposition method. Such devices would have the novelty of high performance, benefiting from the inherited unique properties of the nanomaterials, and can be fabricated on these smooth films using a conventional, low cost planar process. Photoluminescence measurements showed that the NR films have much stronger shallow donor to valence band emissions than those from discrete ZnO NRs, and hence have the potential for the development of ZnO light emission diodes and lasers, etc. The NR films have been used to fabricate large area surface acoustic wave devices by conventional photolithography. These demonstrated two well-defined resonant peaks and their potential for large area device applications. The chemical solution deposition method is simple, reproducible, scalable and economic. These NR films are suitable for large scale production on cost-effective substrates and are promising for various fields such as sensing systems, renewable energy and optoelectronic applications.

Exclusive self-aligned ß-phase PVDF films with abnormal piezoelectric coefficient prepared via phase inversion.

Self-polarised poly(vinylidene fluoride), (PVDF), films were prepared via a facile phase-inversion technique wherein the polymorphism of the films was controlled from exclusive α- (>90%) to ß-phase (>98%) by simply varying the quenching temperature from 100 °C to -20 °C, respectively. At low temperatures, the ß-phase crystallites were found to be self-aligned, with the PVDF thin films possessing a high piezoelectric coefficient of up to -49.6 pm V(-1). The extraordinarily high ß-phase and piezoelectric coefficient of these PVDF films make them suitable for electroactive and energy harvesting applications.