History of development of thermoelectric materials for electric power generation and criteria of their quality

An analysis of results, obtained in the development of thermoelectric materials for electricity generation during the last 130 years, shows that they are comparable to those obtained as early as the nineteenth century. One of the main factors responsible for the stagnation in this area is the use of inappropriate criteria for the evaluation of material quality. The most popular criterion used for this purpose is the Thermoelectric Figure of Merit. The criterion of usefulness proposed in this paper is free of imperfections of the Thermoelectric Figure of Merit and may be considered as alternative to it. The criterion of usefulness shows, among other things, that it is reasonable to develop thermoelectric pairs both with high and relatively low thermoelectric efficiency. Its application would make it possible to avoid the creation of useless materials. This is especially important under conditions of limited research funding.