Patent ID: 9190543
Filing Date: 2015-11-17
Classification: C23C,H01L,Y02E

Abstract:
1. A method of producing a photo-voltaic device, comprising: dissolving metal chalcogenides in a solvent to provide a precursor solution having a concentration of chalcogenides in solution of less than about 1 mmole/ml; heating a substrate to a temperature between 300° C. and 600° C.; spraying at least a portion of said precursor solution onto a structure comprising said substrate to be annealed to form at least part of an active layer of said photo-voltaic device; and varying a concentration of copper in said precursor solution to provide a concentration gradient of copper in a vertical direction as said spraying builds up said active layer in said vertical direction so as to provide an average grain size of at least 20 nm, wherein said concentration of copper in said precursor solution is varied by varying an amount of solvent in said precursor solution.