**Author details**

*Advanced Thermoelectric Materials for Energy Harvesting Applications*

that traditionally reported was up to 5% with the use of Bismuth Telluride (Bi2Te3) composite. The limits of Bismuth Telluride (Bi2Te3)-based thermoelectric material and advancing it with the novel effects of doping the electron properties of Lead Telluride (PbTe) for the improvement of the thermoelectrical performances are discussed in this book. The recent methods for thermoelectric efficiency enhancement with (PbTe)1-*x*(BiTe)*x* alloys could be used to improve electronic optimization. There is a need of improving the efficiency of thermoelectric materials. Balancing the properties of the thermoelectric materials such as lowering the thermal conductivity, which is linked to figure of merit, is important. In this book, the organic (polymer and nanocomposite based) thermoelectric materials are discussed. The significance of organic and inorganic materials, technologies for the fabrication and performance parameters of thermoelectrics are discussed along with carbon-based materials such as graphene and carbon nanotubes for costeffective solutions and enhancement of conversion efficiency. It is also important to understand the quantum theory of the Seebeck coefficient for the advancement of thermoelectric superconducting material which is also discussed in this book. This material incorporates the main superconducting properties such as zero resistance and superconducting temperature higher than the liquid nitrogen temperature. Passive cooling using thermoelectric modules is usually applicable to remote locations where electricity from the grid is not possible, while utilizing the geothermal heat is of great importance in the future, for example, powering the closedcircuit television cameras, LED lightings and mobile cellular devices, which is discussed in detail in this book. A recent development in electronic mobile devices, lighting systems, concentrated quartz-halogen heat and batteries have allowed thermoelectric modules to use its generated power to add up the system efficiency. Thermoelectric generators are bridging their implication to electric vehicles, solar thermal and photovoltaic technologies, in which the scope of harnessing waste heat energy to electrical power is demanding with vacuum insulation [5, 6], and advanc-

ing the performance of thermoelectric materials [7] is of vital importance.

to achieve optimal performance for the recovery of the waste heat.

The question is what the optimum performance of using Bismuth Telluride (Bi2Te3)-based thermoelectric generator would be if the experimental setup is designed specifically for this? In this book, the experimental and simulated thermoelectrical performance parameters, such as the VI characteristic curves at variable temperatures, are analysed. In this, the focus is on harvesting the maximum possible waste direct heat to electrical power with the Bismuth Telluride (Bi2Te3)-based thermoelectric generator and demonstrating the experimental test setup necessary

In terms of specific energy harvesting applications in the modern day, thermoelectric cooling devices could be used to operate ultraviolet LED in its nominal conditions in order to improve its optical performance. To harness the waste heat from the vehicles has already been an industrial automotive focus, and this book explains how waste heat from the exhaust system can be used to harness into useful

However, this book does not stipulate the complete coverage of all the important advanced thermoelectric materials but specifically enlightens the submitted contributions by the authors. This book, nevertheless, provides state-of-the-art advanced thermoelectric materials and a range of energy harvesting technologies that might be helpful to readers to enhance their knowledge and develop eagerness to details in the science and development of thermoelectrics. It is intended that this book will motivate scientists, researchers, engineers and students to investigate further into the modern applications and materials development in the area of thermoelectrics.

**4**

electrical power.

Saim Memon

Centre for Advanced Materials, Division of Electrical and Electronic Engineering, School of Engineering, London South Bank University, London, UK

\*Address all correspondence to: s.memon@lsbu.ac.uk

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Organic Thermoelectrics and

Inorganic and organic thermoelectric (TE) materials have received an extensive scientific interest during the last decades, due to their ability to directly convert the thermal energy to electricity. This is described by the well-known "Seebeck effect". TE materials can convert also electricity into cooling through the "Peltier effect". As such, TE materials and thermoelectric generator (TEG) devices can be utilized for potential applications including (i) thermal energy harvesting, (ii) local cooling and (iii) temperature sensing. The direct conversion of heat into electricity has been one of the most attractive solutions to the severe environmental and energy issues the humanity is coming across. This chapter covers the fundamental working principle of TE materials, the synthetic protocols for inorganic and organic thermoelectric materials, techniques and technologies for the fabrication of thermoelectric generators (otherwise defined as thermoelectric module devices) and a number of applications. Finally, future aspects and outlooks for further

advancements at the "material" or "device" level for efficient power generation are

Due to the finite supply of fossil fuels and the human-induced global climate change, an emerging energy crisis has been realized in the twenty-first century giving rise to the exploitation of "green" energy and alternative energy resources [1–3]. There has been a substantial increase in the consumption of energy resources and especially that of petroleum feedstocks mainly due to (i) the industrial development and (ii) population growth [4]. In industrial environments and our daily life, large amounts of the generated heat energy cannot be effectively used getting

Keywords: Seebeck coefficient, thermoelectric (TE) nanomaterials,

1. Introduction to energy needs and wasted thermal energy

inevitably wasted in the environment, e.g. emissions of factory boilers, car exhausts, friction, etc. A major contributor to waste heat is the transport sector, where only the 20% of the fuel's energy ends up as useful energy. Relatively, aeronautics and automotive are examples of high energy usage with low efficiency, where roughly 75% of the energy produced during combustion is lost in the turbine/ exhaust or engine coolant in the form of heat. In relation, more than 60% of the energy produced in the USA is never utilized, as most of it is dissipated in the form

organic thermoelectrics, thermoelectric generators (TEGs)

Thermoelectric Generators

(TEGs)

Abstract

remarked.

7

Lazaros Tzounis
