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Conducting and Optical Properties of Transparent Conducting Indium-Doped Zinc Oxide Thin Films by Sol-Gel Processing

Description: Transparent conducting oxides were successfully prepared from mixed zinc nitrate hexahydrate and indium nitrate hydrate solutions in ethylene glycol using sol-gel technique. The In content in the film was varied (0, 2, 10, 20, 40, 75 and 100 atom %). Films were prepared by spin coating of the liquid precursors followed by thermal decomposition at 400° C after each layer. According to X-ray diffraction (XRD) measurements, the pure ZnO and pure InO films (0 and at 100 % In) were crystalline as-deposited. The crystallinity was suppressed in mixed compositions such that the films with compositions between 10 and 75 at % were amorphous. All the films were transparent with the transmission cut-off frequency near 400 nm, which is characteristic of TCO materials. All as-deposited films were conductive with 0 and 100 atom % In having the lowest resistivities. The resistivity of all compositions were improved by post-deposition reducing anneal in pure Ar at 300° C. The lowest resistivity of 0.2 Ωcm was obtained for the pure ZnO after Ar anneal. It was two-orders of magnitude higher than reported in the literature for the In-doped ZnO, which was attributed to the low processing temperature. The resistivities of as-deposited and annealed in Ar films were increased by consequent air anneal at 300° C.
Date: January 1, 2004
Creator: Huang, S.; Kaydanova, T.; Miedaner, A. & Ginley, D.S.
Partner: UNT Libraries Government Documents Department

Multi-Layer Inkjet Printed Contacts for Silicon Solar Cells: Preprint

Description: Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. The approach developed can be easily extended to other conductors such as Pt, Pd, Au, etc. Thick highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and printed circuit board (PCB) have been printed at 100-200 C in air and N2 respectively. Ag grids were inkjet-printed on Si solar cells and fired through the silicon nitride AR layer at 850 C, resulting in 8% cells. Next generation inks, including an ink that etches silicon nitride, have now been developed. Multi-layer inkjet printing of the etching ink followed by Ag ink produced contacts under milder conditions and gave solar cells with efficiencies as high as 12%.
Date: May 1, 2006
Creator: Curtis, C. J.; van hest, M.; Miedaner, A.; Kaydanova, T.; Smith, L. & Ginley, D. S.
Partner: UNT Libraries Government Documents Department

Multi-Layer Inkjet Printed Contacts to Si

Description: Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. The approach developed can be easily extended to other conductors such as Pt, Pd, Au, etc. Thick highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and printed circuit board (PCB) have been printed at 100-200 deg C in air and N2 respectively. Ag grids were inkjet-printed on Si solar cells and fired through the silicon nitride AR layer at 850 deg C, resulting in 8% cells. Next generation inks, including an ink that etches silicon nitride, have now been developed. Multi-layer inkjet printing of the etching ink followed by Ag ink produced contacts under milder conditions and gave solar cells with efficiencies as high as 12%.
Date: November 1, 2005
Creator: Curtis, C. J.; van Hest, M.; Miedaner, A.; Kaydanova, T.; Smith, L. & Ginley, D. S.
Partner: UNT Libraries Government Documents Department

Multi-Layer Inkjet Printed Contacts for Si Solar Cells (Poster)

Description: The objective of this report is to develop inkjet printing (including tools, inks, and processing conditions) for high-quality Ag contacts for Si solar cells. The conclusions are: (1) Tools and inks for the atmospheric inkjet printing of Ag metallization for Si solar cells have been developed. (2) Line widths, conductivities and thicknesses comparable to, or better than, those produced by screen printing. (3) A new fire-through ink and layered printing were found to decrease the processing temperature for contact formation to as low as 650 C and improve printed cell performance.
Date: May 1, 2006
Creator: Curtis, C. J.; van hest, M. F. A. M.; Miedaner, A.; Kaydanova, T.; Smith, L. & Ginley, D. S.
Partner: UNT Libraries Government Documents Department

Spray Deposition of High Quality CuInSe2 and CdTe Films: Preprint

Description: A number of different ink and deposition approaches have been used for the deposition of CuInSe2 (CIS), Cu(In,Ga)Se2 (CIGS), and CdTe films. For CIS and CIGS, soluble precursors containing Cu, In, and Ga have been developed and used in two ways to produce CIS films. In the first, In-containing precursor films were sprayed on Mo-coated glass substrates and converted by rapid thermal processing (RTP) to In2Se3. Then a Cu-containing film was sprayed down on top of the In2Se3 and the stacked films were again thermally processed to give CIS. In the second approach, the Cu-, In-, and Ga-containing inks were combined in the proper ratio to produce a mixed Cu-In-Ga ink that was sprayed on substrates and thermally processed to give CIGS films directly. For CdTe deposition, ink consisting of CdTe nanoparticles dispersed in methanol was prepared and used to spray precursor films. Annealing these precursor films in the presence of CdCl2 produced large-grained CdTe films. The films were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). Optimized spray and processing conditions are crucial to obtain dense, crystalline films.
Date: May 1, 2008
Creator: Curtis, C. J.; van Hest, M.; Miedaner, A.; Leisch, J.; Hersh, P.; Nekuda, J. et al.
Partner: UNT Libraries Government Documents Department

Direct-Write Contacts: Metallization and Contact Formation; Preprint

Description: Using direct-write approaches in photovoltaics for metallization and contact formation can significantly reduce the cost per watt of producing photovoltaic devices. Inks have been developed for various materials, such as Ag, Cu, Ni and Al, which can be used to inkjet print metallizations for various kinds of photovoltaic devices. Use of these inks results in metallization with resistivities close to those of bulk materials. By means of inkjet printing a metallization grid can be printed with better resolution, i.e. smaller lines, than screen-printing. Also inks have been developed to deposit transparent conductive oxide films by means of ultrasonic spraying.
Date: May 1, 2008
Creator: van Hest, M. F. A. M.; Curtis, C. J.; Miedaner, A.; Pasquarelli, R. M.; Kaydonova, T.; Hersh, P. et al.
Partner: UNT Libraries Government Documents Department

Polymer Based Nanocomposites for Solar Energy Conversion

Description: Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.
Date: January 1, 2005
Creator: Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C. et al.
Partner: UNT Libraries Government Documents Department

Direct-Write Contacts for Solar Cells

Description: We report on our project to develop inkjet printable contacts for solar cells. Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. Thick, highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and PCB have been printed at 100-200 C in air and N2, respectively. Ag grids were inkjet-printed on Si solar cells and fired through silicon nitride AR layer at 850 C resulting in 8% cells. Next-generation multicomponent inks (including etching agents) have also been developed with improved fire-through contacts leading to higher cell efficiencies. The approach developed can be easily extended to other conductors such as Pt, Pd, and Au, etc. In addition, PEDOT-PSS polymer-based conductors were inkjet-printed with the conductivity as good or better than those of polymer-based conductors.
Date: January 1, 2005
Creator: Kaydanova, T.; van Hest, M.F.A.M.; Miedaner, A.; Curtis, C. J.; Alleman, J. L.; Dabney, M. S. et al.
Partner: UNT Libraries Government Documents Department