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Pyroelectric Nanogenerators in Energy Technology
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Nanogenerators, 2023
Ampattu R. Jayakrishnan, José P. B. da Silva, Sugumaran Sathish, Koppole Kamakshi, Koppole C. Sekhar
Pyroelectric materials are polar materials that have the ability to generate an electric current or potential when they are heated or cooled, and this phenomenon is known as pyroelectric effect or pyroelectricity [9, 10]. The temperature variation induces a net dipole moment change (or bound charges) and consequently, a gross Ps change. The Ps change establishes charges (electrons and ions) on the surface of the pyroelectric material, and these surface charges are responsible for the pyroelectric nature [11].
Pyroelectric and Piezoelectric Polymers
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Polymers in Energy Conversion and Storage, 2022
Pragati Kumar, Lakshmi Unnikrishnan
Piezoelectric materials are subclasses of dielectric materials, whereas pyroelectric materials are subclasses of piezoelectrics, that is all pyroelectrics exhibit piezoelectricity and all piezoelectric materials are dielectric; however, the converse is not true, as illustrated in Figure 6.1. Piezolectricity is the phenomenon of the generation of electricity by the application of force, while the phenomenon of the generation of electricity due to a temperature gradient in the material is known as pyroelectricity.
Gap Solitons in Photorefractive Optical Lattices
Published in Arpan Deyasi, Pampa Debnath, Asit K. Datta, Siddhartha Bhattacharyya, Photonics, Plasmonics and Information Optics, 2021
Pyroelectricity is a phenomenon exhibited in certain materials where an electrical potential is generated due to a finite temperature change resulting in heating or cooling. These effects can be observed in crystals which possess a spontaneous polarization. We can define the pyroelectric coefficient as the change in the electric charge per unit of surface area due to a unit temperature change. Mathematically, the pyroelectric coefficient can be expressed as p = − dPS / dT where PS is the spontaneous polarization.
Temperature-dependent model for ferroelectrics embedded into two-dimensional polygonal finite element framework
Published in Mechanics of Advanced Materials and Structures, 2023
Dheeraj Kailas Valecha, Jayabal K, Amirtham Rajagopal
Potential applications of ferroelectric materials are micromachines & microelectronics. This is due to their excellent pyroelectricity, piezoelectricity, & ferroelectricity. Ferroelectric materials are used in nonvolatile ferroelectric random access memory (FRAM) and data storage systems because they have switchable polarization orientation and can retain a polarization state under the influence of an external electric field. Lead zirconate titanate (PZT) thin films have several benefits when it comes to ferroelectric materials, including ease of incorporation with silicon semiconductor materials, controlled orientation, and superior ferroelectricity.
A strategy for optimal energy conversion by pyroelectricity
Published in International Journal of Green Energy, 2018
Chun-Ching Hsiao, An-Shen Siao, Yi-Je Tsai
Heat remains an almost ubiquitous and abundant ambient source of energy that is often wasted as low-grade waste heat. Low-grade waste heat is greatly generated as a by-product of power, refrigeration or heat pump cycles. Thermoelectric generators with thermoelectric materials have attracted interest as a means for harvesting waste heat; however, they require bulky heat sinks to convert temperature gradients into electrical energy using the Seebeck effect. Pyroelectric materials are of interest because they have the potential to operate with a high thermodynamic efficiency under correct conditions (Sebald, Lefeuvre, and Guyornar 2008). Pyroelectricity is a property whereby a charge is generated on the surface of pyroelectric material as a result of a change in temperature. It manifests itself in polar materials because of the temperature dependence of its electrical polarization. Pyroelectric materials produce power from temperature fluctuations (dT/dt), while thermoelectric systems generate electric power from temperature gradients (dT/dx). If a pyroelectric material is heated (dT/dt> 0), there is a decrease in its level of spontaneous polarization as dipoles within the material lose their orientation due to thermal vibrations. This leads to a decrease in the number of free charges bound to the material’s surface. In open circuit situations, the free charges remain on the electrode’s surface, and an electric potential is produced across the material. In short circuit situations, electric current flows between the two polar surfaces of the material. Furthermore, if the pyroelectric material is cooled (dT/dt< 0), the dipoles regain their orientation for further inducing to increase the level of spontaneous polarization. The electric current flow is reversed under short circuit situations, and free charges are attracted to the polar surfaces. The generated charges yield a voltage across the pyroelectric material before they are released by an external circuit or internal resistance (Sharma et al. 2015). In addition, the microstructure of the pyroelectric materials (such as grain size and porosity) plays a vital role in the pyroelectric response, thermal conductivity and specific heat for further influencing the efficiency in pyroelectric harvesters (Jiang et al. 2015; Zhang et al. 2011a, 2009, 2009b). Although the pyroelectric effect can be used to thermal energy harvesting (Bowen et al. 2014; Yu et al. 2015; Zhang et al. 2018), lead-system materials such as PZT with a high pyroelectric coefficient are widely adopted to enhance the energy conversion efficiency (Zeng et al. 2013; Zhang et al. 2009). Namely, lead may enter the environment from the manufacture of the high lead content materials.