| AVS 58th Annual International Symposium and Exhibition | |
| Energy Frontiers Focus Topic | Thursday Sessions |
| Session EN+NS-ThA |
| Session: | Nanostructures for Energy Storage and Fuel Cells II |
| Presenter: | N.P. Dasgupta, Stanford University |
| Authors: | F. Prinz, Stanford University N.P. Dasgupta, Stanford University C.-C. Chao, Stanford University |
| Correspondent: | Click to Email |
The benefits of utilizing nanoscale materials include high surface to volume ratios, short transport lengths, tunable optical and electronic properties, and the ability to take advantage of quantum mechanical effects in low-dimensional structures. Simple scaling laws indicate how nano scale structures may help improving energy conversion efficiency.
Our group has been focusing on two primary application areas of ALD for energy conversion: fuel cells and photovoltaics. In the area of fuel cells, ALD presents several opportunities for reducing efficiency losses. By fabricating oxide-ion conducting electrolyte materials with thicknesses below 100nm which are pinhole free, we have been able to minimize ohmic losses due to ionic transport, allowing for a reduction in the operating temperature of solid oxide fuel cells (SOFCs)[1]. Furthermore, by fabricating 3-D fuel cell architectures[2] and modifying the surface of the electrolyte with a thin ALD layer[3], we have been able to reduce activation overpotentials in these cells and increase power density.
In the field of solar cells, we have been applying ALD to build quantum confinement structures for bandgap engineering. ALD of PbS thin films was performed, and measurements of the localized density of states (DOS) show the ability to tune the bandgap simply by controlling the number of ALD cycles[4]. We have demonstrated a new technique to directly fabricate quantum dots (QDs) during the initial nucleation cycles of ALD PbS[5]. These QDs were deposited directly on nanowire surfaces, suggesting the ability to combine light trapping in nanostructured templates with quantum confinement effects.
[1] J. H. Shim, C.-C. Chao, H. Huang and F. B. Prinz, Chem. Mater. 19, 3850 (2007).
[2] P.-C. Su, C.-C Chao, J. H. Shim, R. Fasching and F. B. Prinz, Nano Lett. 8, 2289 (2009).
[3] C.-C. Chao, Y. B. Kim and F. B. Prinz, Nano Lett. 9, 3626 (2009).
[4] N. P. Dasgupta, W. Lee and F. B. Prinz, Chem. Mater. 21, 3973 (2009).
[5] N. P. Dasgupta, H. J. Jung, O. Trejo, M. T. McDowell, A. Hryciw, M. Brongersma, R. Sinclair and F. B. Prinz, Nano Lett. 11, 934 (2011).