In addition to sampling helical cores, we have also developed a loop building procedure to complement our core sampling. The combined protocol is able to sample alpha-helical proteins extremely effectively and with considerable speed. A paper describing this method is currently in preparation,
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SUMMARYCulnSe2 (CIS) and related compounds are important photovoltaic materials that have been successfully used for the fabrication of high efficiency polycrystalline thin film solar cells. Despite the impressive results achieved in the laborato~, however, commercialization of CIS based solar cells has been slow. One of the reasons for this is the fact that CIS film growth techniques employed in the research labs are based on vacuum approaches that are difficult and/or expensive to scale up. The objective of this Phase II SBIR program was to develop and demonstrate a low cost, non-vacuum deposition technique for the growth of photovoltaic-grade CIS absorber layers. The technical approach taken in this program was to develop a method that could strictly control the stoichiometric Cu/in ratio in the CIS absorbers since this stoichiometric ratio greatly affects the electrical and optical properties of this group of materials. One other consideration was to demonstrate a coating technique that can, in principle, deposit the CIS absorbers on large area substrates of 4-8 ff size. These goals were successfully reached and a patent application was submitted internationally describing the novel approach developed.The technique involves four steps; i) preparation of a Cu-in alloy powder, ii) preparation of an ink using the Cu-in powder as the pigment, iii) deposition of the ink on the selected substrate in the form of a thin precursor layer, and iv) selenization of the precursor to form the desired CIS compound.The specific tasks that were accomplished in this program were: i) A novel, low cost particle deposition technique was developed. The ability of this technique to strictly control the Cu/in ratio was demonstrated. Ability of the approach to coat large area substrates was confirmed. ii) CIS films with excellent mechanical integrity were deposited on Me/glass substrates without any peeling problems. These layers were studied by SEM and XRD. They were found to be single phase. iii) Solar cells were fabricated on the CIS layers using CdS/ZnO window layers and a total area efficiency of 10.56%, and active area efficiency of 10.9'% were demonstrated. Future work should concentrate on the densification of the compound layers for better cell performance.The results obtained in this project are important for low cost CIS based PV module production. H should be noted that, although the total worldwide PV market has now approached the $1 billion mark, the most important barrier to its explosive expansion is the cost of PV products which, at the present time, are competitive for ma...
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