Effects of Nb-doping on the micro-structure and dielectric properties of (Bi0.5Na0.5)TiO3 ceramics

Bismuth sodium titanate [(Bi_0.5Na_0.5)TiO₃ or BNT] ceramics incorporated with 0, 1, 5, 10, 15 and 20 mol% niobium were prepared by conventional solid state reaction method. The green bodies were sintered at 1050 °C for 2 h to obtain dense ceramics. The effects of substitution of niobium ion for titanium ion in BNT ceramics on micro-structure and dielectric properties were investigated. X-ray diffraction analysis showed the presence of a secondary phase when more than 5 mol% niobium was added. Within the solubility limit, Nb doping caused the grain size of BNTNb to be smaller than the undoped sample. The investigation of the dielectric properties showed that the transition temperature (T_c) was found to shift towards lower temperature as the content of Nb increased. In this research, the donor-type behavior and induced charged defects had significant influence on the electrical properties of Nb-doped BNT ceramics.     

A study of flexible piezoelectric generators by sputtering ZnO thin film on PET substrate

Abstract

Flexible technology has recently received much attention in the field of flexible sensors, wearable electronic devices, flexible transparent displays, and energy harvesters. Zinc oxide (ZnO) thin film is the preferred material for use in flexible devices due to its environmental friendliness, high electrical performance and low synthesis temperature. In addition, ZnO possesses a non-centrosymmetric crystal structure, causing a piezoelectric effect in the material. This work presents the fabrication of flexible piezoelectric generators using the deposition of ZnO on a PET substrate using sputtering techniques. The fabricated flexible generators are capable of generating an output power of 14 µW through an optimal resistive load of 750 kΩ. An output voltage of 2.00 Vp and a current of 150 μA measured across a 750 kΩ resistor were subsequently obtained.     

Fabrication and characterization of flexible piezoelectric composites with natural rubber matrix

Abstract

This work aims to fabricate and characterize flexible piezoelectric composites with natural rubber (NR) matrix. Different amounts of Pb(Mg_1/3Nb_2/3)_0.65Ti_0.35O₃ (PMNT) powders were added in NR matrices. Porosity, tensile strength and percent elongation at break of composites tended to decrease with increasing PMNT content. The dielectric constant of the NR materials was found to be 3.5. It was raised up to 4.2, 5.0, 4.5, 4.8 and 5.1 when 60, 80, 100, 120 and 150 phr PMNT powders were added. However, dielectric loss of NR materials did not change with PMNT additions. Among this composite system, the NR/100PMNT composite showed the best piezoelectric properties, which its output voltage, piezoelectric coefficient (d₃₃) and piezoelectric voltage coefficient (g₃₃) values were equal to 1.61 V, 2.1?×?10^?4 pC/N and 5.4?×?10^?6 V?m/N, respectively. This composition composite is a promising material suitable for further improvement to be used as piezoelectric generators in energy harvesting applications.