Bulletin of the American Physical Society
Fall 2009 Meeting of the Four Corners Section of the APS
Volume 54, Number 14
Friday–Saturday, October 23–24, 2009; Golden, Colorado
Session C7: Symposium on Renewable Energy -- PV |
Hide Abstracts |
Chair: Joe Beach, Colorado School of Mines Room: Green Center 263 |
Friday, October 23, 2009 3:40PM - 3:52PM |
C7.00001: Single Molecule Lifetime Studies of Small Clusters of Semiconductor Nanocrystals Douglas Shepherd, Kevin Whitcomb, Peter Goodwin, Martin Gelfand, Alan Van Orden Enhanced fluorescence intermittency has been reported in single molecule fluorescence experiments on small clusters of semiconductor nanocrystals$^{1}$, and single Mn$^{2+}$ doped semiconductor nanocrystals$^{2}$. This behavior is attributed to electronic coupling between nanocrystals in the clusters. We report here on further studies of small clusters of semiconductor nanocrystals utilizing single molecule time-correlated single photon counting, which provides insight into the nature of the coupling. According to this analysis, clusters typically blink on a microsecond to millisecond time scale; whereas, isolated nanocrystals blink on much longer millisecond to second time scale. 1. Yu, M. and A. Van Orden, \textit{Enhanced Fluorescence Intermittency of CdSe-ZnS Quantum-Dot Clusters.} Physical Review Letters, 2006. \textbf{97}(23): p. 237402-4 2. Yanpeng Zhang, C.G., Javed Muhammad, David Battaglia, Xiaogang Peng and Min Xiao, \textit{Enhanced Fluorescence Intermittency in Mn-Doped Single ZnSe Quantum Dots.} Journal of Physical Chemistry C, 2008. \textbf{112}(51): p. 20200-20205 [Preview Abstract] |
Friday, October 23, 2009 3:52PM - 4:04PM |
C7.00002: Surface Modification of Zinc Oxide Nanorods Darick Baker, Christian Weigand, Jamie Adamson, Cary Allen, Matt Bergren, Dana Olson, Cecile Ladam, David Ginley, Reuben Collins, Thomas Furtak Zinc oxide (ZnO) nanorod arrays have a number of advantages over both planar ZnO/P3HT and ZnO/P3HT:PCBM blend solar cell devices. In this study, molecular surface modifications of the ZnO have been explored as a strategy for improving both charge transfer and polymer morphology at the ZnO surface. Surface molecular layers were formed on planar ZnO and ZnO nanorod arrays using octadecyltriethoxysilane, phenyltriethoxysilane, octadecanethiol, and thiophenol. FTIR, SEM, UV-Vis, XPS and contact angle data were used to characterize the resulting layers. The effects of these surface treatments on solar cells are reported. Molecular layers with different attachments to the ZnO but the same terminal group showed different behavior, confirming that both the terminal and attachment group play important roles in interface structure, energetics, and charge transfer. This research is aimed at improving organic solar cell performance, yet is applicable to a broad range of hybrid organic/inorganic systems. Support from NSF Awards DMR-0606054 and DMR-0820518 is gratefully acknowledged. [Preview Abstract] |
Friday, October 23, 2009 4:04PM - 4:16PM |
C7.00003: Studying the Nanostructure of Hydrogenated Nanocrystalline Silicon Thin Films K.G. Kiriluk, D.L. Williamson, P.C. Taylor, B. Yan, J. Yang, S. Guha Hydrogenated nanocrystalline silicon (nc-Si:H) is increasingly being used as the bottom layer in multi-junction solar cells. In order to better understand its growth and unique optoelectronic properties, we have used x-ray diffraction (XRD) and small angle x-ray scattering (SAXS) experiments to study its nanostruture. The XRD patterns indicate approximately 20 nm crystallites that are preferentially oriented in the (220) direction. The SAXS intensities indicate that these crystallites are elongated in the growth direction with a width of approximately three to four times less than the length. Combined, these results show ellipsoidal grains oriented in the growth direction. Transmission electron microscopy (TEM) images corroborate these results. The work performed at the Colorado School of Mines is partially supported by NSF under grant number DMR-0702351, by the NSF MRSEC program under grant number DMR-08-20518, and by DOE under subcontract number DE-FC36-07G017053. The work done at United Solar Ovonic is also partially supported by DOE under subcontract number DE-FC36-07G017053. [Preview Abstract] |
Friday, October 23, 2009 4:16PM - 4:28PM |
C7.00004: Growth of Tin Seeded Silicon Nanowires (SiNWs) Using Plasma Enhanced Chemical Vapor Deposition Somilkumar Rathi, Joseph Beach, Jeremy Fields, Bhavin Jariwala, Sumit Agarwal, Reuben Collins, Pauls Stradins Silicon nanowires (SiNWs) have attracted much attention among the photovoltaic community. With high surface to volume ratios, these nanowires are ideal candidates for nano-structured solar devices. Considerable effort has been put towards the growth and characterization of these nanowires. However, growing high quality SiNWs for PV applications is still considered to be a challenge. The role of different metal seeds during vapor-liquid-soild (VLS) growth and the electronic properties of these wires is also investigated. The present study extends the available literature on the use of Sn as a metal catalyst for VLS growth of SiNWs [Preview Abstract] |
Friday, October 23, 2009 4:28PM - 4:40PM |
C7.00005: Electron Reflector to Enhance Photovoltaic Efficiency: Application to Thin-Film CdTe Kuo-Jui Hsiao Numerically, electron reflector, which is a strategy to enhance the efficiency of photovoltaic devices, is applied to thin-film CdTe record-cell baseline model (efficiency = 16.5{\%}). Simulation shows that to have the optimal effect from electron reflector, thinning cells to few microns is required. Moreover, thin cells (absorber layer below two microns) will have additional benefit from the optical reflection from the back surface. Theoretically, more than 19.5{\%} efficiency is achievable with 0.2-eV electron reflector, 1-micron absorber layer, 10$^{14}$ cm$^{-3}$ hole density, and 1-ns lifetime. Moreover, 20{\%} efficiency is possible with the consideration of 100{\%} optical reflection. Realistic case should have the performance in the case between 20 and 100{\%} optical reflection. This work gives thin-film CdTe cell an approach to 3{\%} increase in efficiency. [Preview Abstract] |
Friday, October 23, 2009 4:40PM - 4:52PM |
C7.00006: Interference Lithography for Vertical Photovoltaics Amy Balls, Lei Pei, Joshua Kvavle, Andrew Sieler, Stephen Schultz, Matthew Linford, Richard Vanfleet, Robert Davis We are exploring low cost approaches for fabricating three dimensional nanoscale structures. These vertical structures could significantly improve the efficiency of devices made from low cost photovoltaic materials. The nanoscale vertical structure provides a way to increase optical absorption in thin photovoltaic films without increasing the electronic carrier separation distance. The target structure is a high temperature transparent template with a dense array of holes on a 400 - 600 nm pitch fabricated by a combination of interference lithography and nanoembossing. First a master was fabricated using ultraviolet light interference lithography and the pattern was transferred into a silicon wafer master by silicon reactive ion etching. Embossing studies were performed with the master on several high temperature polymers. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700