Effect of annealing temperature on the morphology and piezoresponse characterisation of poly(vinylidene fluoride-trifluoroethylene) films via Scanning Probe Microscopy

Poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE (70/30)) films were synthesized on a gold/glass substrate via spin coating. The films were annealed at a temperature between 125°C and 180°C. Nanoscale characterisation of the morphology, polarizat

Patterned photochemical deposition on domain engineered ferroelectric single crystals

The photochemical deposition of silver on (001)-oriented 0.25Pb(In1/2Nb1/2)O3-0.44Pb(Mg1/3Nb2/3)O3-0.31PbTiO3 (PIN-PMN-PT) ferroelectric single crystals is investigated via piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM). Selective photochemical deposition within c+ domains is attained by manipulating the photoreaction time. Enhanced photochemical reduction at c-/c+ domain boundaries is achieved by controlling the domain poling voltage and the scanning direction of the tip during domain switching. These phenomena are explained by polarisation band bending at domain boundaries and tip induced charge injection during domain switching. This work provides insight into obtaining an arbitrary spatial distribution of photodeposited metal on ferroelectric materials

Domain-selective photochemical reaction on oriented ferroelectric Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 single crystals

The domain-selective photoreduction of silver on (0 0 1) and (1 1 1) oriented 0.25Pb(In1/2Nb1/2)O3-0.44Pb(Mg 1/3Nb2/3)O3-0.31PbTiO3 (PIMNT) ferroelectric single crystals is investigated via piezoresponse force microscopy and Kelvin force microscopy. It is found that the crystallographic orientation as well as the direction and magnitude of the voltage used for domain switching strongly affects the amount and distribution of silver photodeposition. Additionally, the scanning direction of the tip during domain switching significantly affects silver photodeposition at c-/c+ domain boundaries when a high voltage is applied for domain switching. These phenomena can be explained and thus controlled by polarisation induced band bending, the space charge layer of the ferroelectric crystal and tip induced charge injection during domain switching. This work demonstrates a potential means to achieve an arbitrary spatial distribution of photodeposited metal

Ferroelectric domain engineered photochemical deposition for area-selectable broadband enhancement of quantum dot photoluminescence

We acknowledge financial support from the Australian Research Council

Colossal Dielectric Permittivity in (Nb+Al) Codoped Rutile TiO 2 Ceramics: Compositional Gradient and Local Structure

(Nb+Al) codoped rutile TiO2 ceramics with nominal composition Ti4+0.995Nb5+0.005yAl3+0.005zO2, z = (4-5y)/3 and y = 0.4, 0.5, 0.6, 0.7, and Ti4+0.90Nb5+0.05Al3+0.05O2 have been synthesized. The resultant samples in ceramic pellet form exhibit a colossal dielectric permittivity (>-104) with an acceptably low dielectric loss (-10-1) after optimization of the processing conditions. It is found that a conventional surface barrier layer capacitor (SBLC) effect, while it contributes significantly to the observed colossal permittivity, is not the dominant effect. Rather, there exists a subtle chemical compositional gradient inward from the pellet surface, involving the concentration of Ti3+ cations gradually increasing from zero at the surface without the introduction of any charge compensating oxygen vacancies. Instead, well-defined Gr ± 1/3[011]∗ satellite reflections with the modulation wave-vector q = 1/3[011]r∗ and sharp diffuse streaking running along the Gr ± ε011]∗ direction from electron diffraction suggest that the induced additional metal ions appear to be digested by a locally intergrown, intermediate, metal ion rich structure. This gradient in local chemical composition exists on a scale up to submillimeters, significantly affecting the overall dielectric properties. This work suggests that such a controllable surface compositional gradient is an alternative method to tailor the desired dielectric performance