Laser Flash Analiysis for bulk thermoelectric materials: realtion between thermal conductivity and electricaal properties

Thermoelectric effects has been used for about two centuries to convert electricity into heat flux or temperature differences into electrical power. Thermoelectric Generators (TEGs) are commonly employed in remote and off grid applications or where their strengths (absence of moving parts, compactness, reliability, modularity...) overcame their limited conversion efficiency. Since the efficiency results proportional to the electrical/thermal conductivity ratio, many efforts are devoted to reduce materials thermal conductivity value without lowering the electrical one. Laser Flash Analysis is widely considered as the reference technique for thermoelectric materials thermal diffusivity measurement. This is due to the technique accuracy, even for small samples and high temperatures. Furthermore the technique allow for specific heat measurement with an accuracy in some cases comparable with calorimetric techniques. Aside the contribution of electrical conductivity to thermal conductivity, in this presentation also the role of thermal conductivity on electrical properties, namely the Seebeck coefficient, is presented.