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The energy cost and global warming associated to fossil fuel sources has motivated the search for cleaner, more sustainable energy sources. Among the different feasible technologies, thermoelectric (TE) energy converters have gained attention lately since these solid-state devices can harvest waste heat into electricity, thereby improving the system´s efficiency. The advantages of TE devices versus conventional heat converters are that they are solid-state devices, so they have no noise, zero-emissions, vast scalability, no maintenance and a long operating lifetime. These TE devices can be used not only for power generation but for refrigeration and cooling. The main drawback of this technology is that the state of the art devices has a low efficiency around 10% (ZT~1). Due to that they are currently limited to niche applications. This efficiency is directly related to a dimensionless figure of merit (ZT):

 


where S is Seebeck coefficient , σ is electrical conductivity, κ is thermal conductivity and T is temperature.

To compete with conventional refrigerators, a ZT=3 should be achieved. Although, a device with ZT>2 will be also important in other applications.

However, there is a renewed interest in the field of thermoelectrics due to quantum size effects, which provide additional ways to enhance energy conversion efficiencies in nanostructured materials. For example, a ZT up to 2.5 was achieved by synthesizing multilayers of Sb2Te3/Bi2Te3 through a chemical vapor deposition (CVD) process, exceeding previous limits of ≈1 for bulk counterparts; theoretical calculations predict that even higher ZTs can be achieved in one-dimensional nanowires.

The successful application of these nanostructures in practical thermoelectric devices must implement a cost-effective and high through-put fabrication process. Among the different techniques electrodeposition has been one of the more successful.

The aim of this group is to develop nano-engineered high performance thermoelectric materials, devices and systems.