| AVS 59th Annual International Symposium and Exhibition | |
| Energy Frontiers Focus Topic | Thursday Sessions |
| Session EN+NS-ThA |
| Session: | Thermophotovoltaics, Thermoelectrics and Plasmonics |
| Presenter: | M.D. Losego, North Carolina State University |
| Authors: | M.D. Losego, North Carolina State University K.A. Arpin, University of Illinois at Urbana Champaign B. Kalanyan, North Carolina State University P.V. Braun, University of Illinois at Urbana Champaign G.N. Parsons, North Carolina State University |
| Correspondent: | Click to Email |
Materials with photonic bandgaps are generated by periodic mesostructuring at length-scales comparable to visible wavelengths. While photonic bandgaps are often used to control the interaction of incident light with a material (e.g. reflect incident light over a narrow bandwidth), these structures can also be used to tune the thermal emission of light. Consequently, a heated metallic photonic crystal could be used in a thermophotovoltaic (TPV) device scheme. Such a TPV would (1) absorb broadband incident solar radiation, (2) heat up, and (3) re-emits the radiation over a narrow band of energies. This narrow-band radiation could then be converted to electricity with high efficiencies using a simple single-junction solar cell. However, demonstrating narrow-band thermal emission from a multidimensional architecture remains elusive. The central challenge is finding a materials set that demonstrates the required combination of thermal stability and dielectric function in a nanostructured architecture capable of high-temperature radiant emission.
This talk will examine our development of refractory tungsten inverse-opal structures designed for thermal emission in the visible spectrum. The first generation of these structures were constructed from silica opals infiltrated with electrodeposited tungsten. While ultrathin (<20 nm) oxide ALD layers were found to improve high temperature stability (>1000°C, 12 hours) by restricting surface diffusion and limiting sintering, difficulties with massive structural cracking during the molten-salt electrodeposition process could not be overcome. Second generation devices are now being developed using a lower temperature tungsten atomic layer deposition (ALD) process. Besides the avoidance of massive structural cracking, these ALD materials appear to be denser than electrodeposited materials, further reducing the unwanted sintering effects at high temperatures. Room temperature spectra collected from these structures indicate photonic effects not seen in planar tungsten films and suggest enhanced thermal emission at visible wavelengths.