Here is the abstract you requested from the CICMT_2011 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Novel Thermoelectric Materials for Thermophotovoltaic Hybrid Devices|
|Keywords: Hybrid Devices, Materials, Thermoelectric|
|We have recently proposed thermophotovoltaic hybrid devices consisted of three parts: dye-sensitized solar cell (DSSC), selective light absorber, and thermoelectric (TE) module, which can convert both UV-VIS light and IR light into electricity with high energy conversion efficiency as high as 14 % or higher. Even though TE module based on conventional bismuth telluride (BT) materials is beneficial for this hybrid device, they must be replaced by other good TE materials because BT materials have many problems in terms of toxicity, low natural abundance, heavy weight, high cost, etc. We have been engaged in developing novel thermoelectric materials to be used for energy saving and environmental protection and are currently developing nanostructured TE materials for low to mid-temperature applications. We have demonstrated a quantum confinement effect giving rise to two dimensional electron gas (2DEG) in a 2D superlattice, SrTiO3/SrTiO3:Nb, which could generate giant thermopower while keeping high electrical conductivity. Then, a “synergistic nanostructuring” concept incorporating 2DEG grain boundaries as well as nanosizing of grains has been applied to our SrTiO3 material and 3D superlattice ceramics was designed and proposed. This 3D superlattice ceramics was verified by numerical simulation to be capable of showing ZT>0.8 @300K which is comparable to that of conventional bismuth telluride-based thermoelectrics. We also have recently proposed TiS2-based misfit-layered compounds as novel TE materials. Insertion of misfit-layers into the van der Waals gaps in layer-structured TiS2 thus forming a natural superlattice gives rise to internal nanointerfaces and dramatically reduces its lattice thermal conductivity. ZT value reaches 0.37 at 673 K even without optimization of electronic properties. Our challenge to further increase ZT by controlling their electronic system and superlattice structures will be presented.|
|Kunihito Koumoto, Professor
Nagoya University and CREST