Thermoelectric chalcogenide materials

Chalcogenide-based thermoelectric generators (TEG) have attracted a lot of attention and have been intensively studied, as there is a high demand for clean energy. The thermoelectric effect is the physical phenomena which converts the temperature difference across p and n-type semiconductors to generate electric voltage directly, and vice versa.

Among the chalcogenide family, bismuth telluride (BiTe) and its alloy bismuth antimony telluride (BiSbTe) are recognised as the most efficient thermo-electric p and n-type materials in both bulk and thin film applications because they have an excellent Seebeck value as well as high electrical conductivity and low thermal conductivity, which result in a high figure of merit (ZT). The BiTe alloys (Bi2Te3 and Bi0.5Sb1.5Te3) have been used in commercial applications for years.

High throughput development of thermoelectric materials

We have applied our evaporative high-throughput physical vapour deposition (HT-PVD) method to produce compositional gradient thin film libraries of the amorphous alloy system. We have developed a new primary screening methodology, HT-SCPS (High Throughput Seebeck Coefficient Probe Station), which provides the Seebeck coefficient value measurements across the compositional changes in binary and ternary systems.

Combined with a primary screening of the electrical contrast associated with crystallization, and full primary compositional (EDX) and structural (XRD) characterization, we demonstrate a rapid method for the preliminary optimization of materials for potential application in TEG.

The TEG can be also fabricated on polyimide substrate to be adopted on the flexible applications.

We are now investigating novel materials for thermoelectric applications including a range of sulphur based chalcogenide materials.