Odyssey of thermoelectric materials: foundation of the complex structure

Growing energy crises and pollution are the major issues of the modern world. The thermoelectric concept seems to be the promising solution to deal with these problems, because of the ability of thermoelectric materials to convert waste heat into electricity without adding more pollution to the atmosphere. The development of thermoelectric materials (TE) is driven by fundamental interest and their potential applications. To replace the conventional techniques, the figure of merit (zT) of the thermoelectric materials should be higher than 2 for power generation and greater than 3 for cooling. Recently, there have been significant advances in enhancing the figure of merit of thermoelectric materials and also to find new materials for the thermoelectric purpose. Low thermal conductivity is the key for a promising thermoelectric material that can be achieved through the complex structures. This review provides insights into the recent advancements in improving the efficiency of thermoelectric systems, complex nature of thermoelectric materials, with a concise introduction to preparative approaches for thermoelectric (TE) materials.