Sol–gel assisted preparation and characterization of silver indium diselenide powders

AgInSe2 powders were successfully prepared via mixing sol–gel derived precursors, followed by a selenization process. To obtain the pure AgInSe2 compound, excess amounts of In3+ ions were added into the starting solution to compensate the loss of In2O3 during the selenization process. A figure that depicts the relationship between the resultant compounds and different selenization temperatures was constructed according to the formed phases. The Raman spectrum and Rietveld refinement confirmed that the prepared AgInSe2 belonged to the chalcopyrite structure. With increasing selenization temperatures, the AgInSe2 powder particle sizes as well as the crystallinity increased significantly. The AgInSe2 formation mechanism during the selenization process is 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 pure AgInSe2 powders for use in thin-film solar cells.

• AgInSe2 powders used for solar cells have been successfully prepared via a new sol–gel assisted process.
• AgInSe2 powders were prepared via mixing sol–gel derived precursors, followed by a selenization process. This process can greatly reduce the required temperatures.
• The phase purity significantly depends on the amounts of In3+ ions. Excess amounts of In3+ ions are needed to add into the starting solution to compensate the loss of In2O3 for obtaining pure AgInSe2.
• A figure that depicts the relationship between the resultant compounds and different selenization temperatures is constructed according to the formed phases.
• The AgInSe2 formation mechanism during the selenization process is proposed. Ag2Se is formed in the first step and subsequently reacts with selenium to form AgInSe2 in the second-step.