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

Abstract

The present invention provides a method for forming a black electrode by performing sintering at a temperature in the range of 500-600° C. after applying a lead-free black conductive composition to a substrate. The aforementioned black electrode comprises a binder comprising a crystallized glass component. The aforementioned black conductive composition comprises conductive particles of black RuO 2 , lead-free black ruthenium-based polyoxide, and mixtures thereof in an amount of 4-30 wt %, based on the total weight of the composition, a lead-free non-conductive black oxide in an amount of 0-30 wt %, based on the total weight of the composition, and a lead-free bismuth-based glass binder in an amount of 10-50 wt %, based on the total weight of the composition.

1 . 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 RuO 2 , 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 Bi 2 O 3 ; ZnO, and B 2 O 3  and wherein Bi 2 O 3  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, Co 3 O 4 , 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. 
   
     
     
         2 - 7 . (canceled) 
     
     
         8 . A black electrode formed by the method of  claim 1 . 
     
     
         9 . A black electrode formed from a method 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 RuO 2 , 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, based on weight percent total glass binder: 0-5% BaO, 2-15% B 2 O 3 , 0-3% SiO 2 , 0-1% Al 2 O 3 , 8-20% ZnO, and 70-90% Bi 2 O 3 ;   (c) 0-30 weight percent lead-free non-conductive black oxide; and wherein the surface area to weight ratio of the conductive metal oxides are in the range of 2-20 m 2 /g;   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.