Black conductive thick film compositions, black electrodes, and methods of forming thereof

A method of forming a lead-free black electrode comprising:

• supplying a substrate;
• supplying a lead-free black conductive composition comprising, based on the weight percent of the total composition (a) 4-30 weight percent conductive metal oxides selected from RuO2, one or more lead-free ruthenium-based polyoxides, and mixtures thereof, (b) 10-50 weight percent lead-free bismuth-based glass binder, wherein said glass binder comprises Bi2O3;
• ZnO, and B2O3 and wherein Bi2O3 is present in an amount of 70-90 weight percent, based on the total weight of said glass binder;
• and
• (c) 0-30 weight percent lead-free non-conductive black oxide selected from the group consisting of Cr—Fe—Co type oxide. Cr—Cu—Co type oxide. Cr—Cu—Mn type oxide, Co3O4, and mixtures thereof;
• applying said black conductive composition onto said substrate;
• and
• sintering at a temperature in the range of 500-600° C. to form a black electrode;
• and wherein said black electrode comprises a crystallized glass component over the entire sintering range of 500° C.-600° C.