Piezoelectric energy materials

Piezoelectric energy is a form of electric energy produced by certain solid materials when they are deformed. (The word piezo has its roots in the Greek word piezein meaning to press. ) Discovery of the piezoelectric effect is credited to Pierre and Jacques Curie who observed in 1880 that certain quartz crystals produced electricity when put under pressure. 

Cook-Chennault, K.A. (2008) Powering MEMS portable devices - a review of non-regenerative and regenerative power supply systems with special emphasis on piezoelectric energy harvesting systems. Smart Materials and Structures, 17, 043001. 

Erturk, A., Inman, D.J., 2009. An experimentally vaUdated himorph cantilever model for piezoelectric energy harvesting from base excitations. Smart Materials and Structures 18,025009. 

Tantalum and niobium are added, in the form of carbides, to cemented carbide compositions used in the production of cutting tools. Pure oxides are widely used in the optical industiy as additives and deposits, and in organic synthesis processes as catalysts and promoters [12, 13]. Binary and more complex oxide compounds based on tantalum and niobium form a huge family of ferroelectric materials that have high Curie temperatures, high dielectric permittivity, and piezoelectric, pyroelectric and non-linear optical properties [14-17]. Compounds of this class are used in the production of energy transformers, quantum electronics, piezoelectrics, acoustics, and so on. Two of... 

The basis for the present-day generation of ultrasound was established as far back as 1880 with the discovery of the piezoelectric effect by the Curies [1-3]. Most modern ultrasonic devices rely on transducers (energy converters) which are composed of piezoelectric material. Such materials respond to the application of an electrical potential across opposite faces with a small change in dimension. This is the inverse of the piezoelectric effect and will be dealt with in detail later (Chapter 7). If the potential is alternated at high frequencies the crystal converts the electrical energy to mechanical... 

The use of biological materials as coatings for piezoelectric crystals was first demonstrated by Shons et al. [237], who immobilized bovine serum albumin (BSA) on a crystal precoated with a 30% solution of Nyebar C, a low-surface energy plastic. The rationale of using this solution as the coating material is that proteins adsorbed on low-energy surfaces retain their antigenic properties. Exposure of the BSA-coated crystal to a solution... 

This is the efficiency of energy conversion between mechanical and electrical forms. For PZTs, it ranges from 0.5 to 0.7, which are the most efficient of all known piezoelectric materials (see Table 9.1). For quartz, the coupling constant is about 0.1. 

Order parameters may also refer to underlying atomic structure or symmetry. For example, a piezoelectric material cannot have a symmetry that includes an inversion center. To model piezoelectric phase transitions, an order parameter, r], could be associated with the displacement of an atom in a fixed direction away from a crystalline inversion center. Below the transition temperature Tc, the molar Gibbs free energy of a crystal can be modeled as a Landau expansion in even powers of r (because negative and positive displacements, 77, must have the same contribution to molar energy) with coefficients that are functions of fixed temperature and pressure,... 

A piezoelectric mass sensor is a device that measures the amount of material adsorbed on its surface by the effect of the adsorbed material on the propagation of acoustic waves. Piezoelectric devices work by converting electrical energy to mechanical energy. There are a number of different piezoelectric mass sensors. Thickness shear mode sensors measure the resonant frequency of a quartz crystal. Surface acoustic wave mode sensors measure the amplitude or time delay. Flexure mode devices measure the resonant frequency of a thin Si3N4 membrane. In shear horizontal acoustic plate mode sensors, the resonant frequency of a quartz crystal is measured. 

The practical application of ultrasonics requires effective transducers to change electrical energy into mechanical vibrations and vice versa. Transducers are usually piezoelectric, ferroelectric, or magnetostrictive. The application of a voltage across a piezoelectric crystal causes it to deform with an amplitude of deformation proportional to the voltage. Reversal of the voltage causes reversal of the mechanical strain. Quartz and synthetic ceramic materials are used. 

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