Preparation and Characterization of Silver Indium Diselenide Used as the Absorber in Thin-film Solar Cells
Date Issued
2010
Date
2010
Author(s)
Chien, Szu-Chia
Abstract
AgInSe2 powders were successfully prepared via mixing the sol-gel derived precursors, followed by a selenization process. A figure depicted the relation between resultant compounds and different selenization temperatures were constructed according to the formed phases. The Raman spectrum and the Rietveld refinement confirmed that the prepared AgInSe2 belonged to the chalcopyrite structure. With increasing the selenization temperatures, the particle sizes of AgInSe2 powders as well as the crystallinity of AgInSe2 powders increased significantly. The formation mechanism of AgInSe2 during the selenization process was proposed as a two-step process. Ag2Se is formed in the first step and then induces the second-step reaction to produce AgInSe2. The sol-gel route with a selenization process is introduced as a new approach to fabricate the pure AgInSe2 powders for using in thin-film solar cells.
In the second part of this study, single-phased AgInSe2 thin films were successfully prepared via depositing the sol-gel derived precursors on the substrates, followed by a selenization process. The pure-phased AgInSe2 thin films were obtained at the selenization temperature as low as 400℃ via adding the excess amount of In3+ ions. Adjusting the In3+/Ag+ molar ratios can effectively prevent the formation of impurities Ag2Se and AgIn5Se8 in thin films. A Raman spectrum indicated that the obtained films belonged to chalcopyrite structure. The optical absorption revealed that the obtained AgInSe2 had the band gap of 1.23 eV. According to the GIXD analysis of the prepared films, the formation mechanism of AgInSe2 thin films is proposed. At first, Se vapor reacted with Ag to produce Ag2Se. Then Se vapor, In2O3 and the formed Ag2Se react with each other to form AgInSe2. The sol-gel route with a selenization process provides a potential way to obtain AgInSe2 thin films with close-packed microstructures.
Subjects
AgInSe2
thin-film solar cell
sol-gel
Type
thesis
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