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Surfactant-Assisted Hydrothermal Synthesis of Single Phase Pyrite FeS2 Nanocrystals

Description: Iron pyrite nanocrystals with high purity have been synthesized through a surfactant-assisted hydrothermal reaction under optimum pH value. These pyrite nanocrystals represent a new group of well-defined nanoscale structures for high-performance photovoltaic solar cells based on non-toxic and earth abundant materials.
Date: March 27, 2009
Creator: Wadia, Cyrus; Wu, Yue; Gul, Sheraz; Volkman, Steven; Guo, Jinghua & Alivisatos, Paul
Partner: UNT Libraries Government Documents Department

Transparent Conducting Oxides: Status and Opportunities in Basic Research

Description: In this paper, we begin by discussing the historical background of transparent conducting oxides and then make some general remarks about their typical properties. This is followed by a short discussion of the desired properties for future applications (particularly photovoltaic devices). These are ambitious objectives but they provide targets for future basic research and development. Although it may be possible to obtain these properties in the laboratory, it is vital to ensure that account is taken of industrial perceptions to the development of the next generation of materials. Hence, we spend some time discussing industrial criteria. Next, we discuss key physical properties that determine the macroscopic physical properties that, in turn, affect the performance of devices. Finally, we select several key topics that ought to be included in future basic research programs.
Date: August 1, 1999
Creator: Coutts, T. J.; Perkins, J. D.; Ginley, D.S. & Mason, T. O.
Partner: UNT Libraries Government Documents Department

Characterization of amorphous silicon thin films and PV devices: Phase 1 annual technical report: January 1998--January 1999

Description: Major accomplishments of the previous year include: (1) an evaluation of the potential for n-type doping of a-SiS{sub x}:H and a-SiSe{sub x}:H alloys, (2) an investigation of the optically induced metastabilities in a-SiS{sub x}:H and a-SiSe{sub x}:H alloys with regard to their potential use in photovoltaic applications, and (3) a more detailed understanding of the kinetics of light-induced electron spin resonance (ESR) due to carriers trapped in localized band-tail states in a-Si:H. Also of importance are preliminary measurements of the defects and metastabilities in hot-wire samples of a-Si:H and in samples of a-Si:H made under strong hydrogen dilution. The preliminary measurements on hydrogen dilution suggest that the production of neutral silicon dangling bonds is not suppressed from the standard material even though there appears to be an improvement in the stability of cells made using the hydrogen-dilution process. The new three-chamber, load-locked plasma-enhanced chemical vapor deposition system is functioning and producing intrinsic and doped films of a-Si:H. Plans for the next year include the production of high quality devices using this new deposition system.
Date: October 27, 1999
Creator: Taylor, P.C.
Partner: UNT Libraries Government Documents Department

Thermophotovoltaic Cell Temperature Measurement Issues

Description: The power produced by photovoltaic devices changes with temperature, ranging from 0.1% to nearly 1% per degrees Celsius depending on the structure. The temperature across the surface of TPV cells will vary depending on the amount of absorbed power. Thus the temperature over a region of a wafer where there is no cell will be different from a region of the wafer containing a cell with an antireflection coating and back surface reflector. Vacuum hold-downs or back surface probes may result in local hot spots. Bonding a cell to a heat sink may not be practical in a research environment, and a temperature gradient between the heat sink and space-charge region will still exist. Procedures for determining the current versus voltage (I-V) characteristics at a given temperature are discussed. For continuous illumination measurement systems, the temperature of the heat sink or backside of the device can be directly measured. The temperature can also be inferred by placing the sample at a known temperature in the dark, and monitoring the open-circuit voltage (Voc) as a high-speed shutter is opened. The maximum Voc from this method corresponds to the temperature in the dark and the plate temperature can then be lowered until this maximum Voc is reached. The temperature can also be indirectly determined from the dark I-V characteristics, assuming negligible series resistance in the ideal case that the voltage in the dark at a given current and temperature corresponds to the Voc and short circuit voltage (Isc) at that temperature. A high-intensity flash simulator will produce negligible cell heating during the flash and therefore the cell temperature may be easily set before the flash.
Date: November 13, 1998
Creator: Emery, K. & Moriarty, T.
Partner: UNT Libraries Government Documents Department