Glass frit, composition for solar cell electrodes including the same, and electrode fabricated using the same
A glass frit includes at least three metal oxides selected from the group of lead oxide, silicon oxide, tellurium oxide, bismuth oxide, zinc oxide, and tungsten oxide, wherein the glass frit exhibits a phase transition peak in the range of about 300° C. to about 600° C. on a cooling curve obtained via an TG-DTA analysis while a mixture of the glass frit and silver powder, obtained by mixing the glass frit with the silver powder in a weight ratio of 1:1, is cooled at a cooling rate of 10° C./min, after heating the mixture to 850° C. at a heating rate of 20° C./min and held there for a wait-time of 10 minutes.
1. A glass frit, comprising:
20 wt % to 60 wt % of tellurium oxide;
zinc oxide;
lead oxide; and
bismuth oxide; and
optionally silicon oxide; and
optionally tungsten oxide;
wherein:
the glass frit exhibits a phase transition peak in the range of 300° C. to 600° C. on a cooling curve obtained via an TG-DTA analysis while a mixture of the glass frit and silver powder, obtained by mixing the glass frit with the silver powder in a weight ratio of 1:1, is cooled at a cooling rate of 10° C./min, after heating the mixture to 850° C. at a heating rate of 20° C./min and held there for a wait-time of 10 minutes,
a weight ratio of the tellurium oxide to the lead oxide is 1:0.1 to 1:3, and a weight ratio of the tellurium oxide to the bismuth oxide is 1:0.1 to 1:3, and
the amount of zinc oxide is 6 to 10 wt % of the glass frit.
2. A composition for solar cell electrodes, the composition comprising:
60 wt % to 90 wt % of a conductive powder;
1 wt % to 10 wt % of the glass frit as claimed in claim 1 ; and
5 wt % to 30 wt % of an organic vehicle.
3. The composition as claimed in claim 2 , wherein the conductive powder includes at least one selected from the group consisting of silver, gold, palladium, platinum, copper, chromium, cobalt, aluminum, tin, lead, zinc, iron, iridium, osmium, rhodium, tungsten, molybdenum, nickel, and indium tin oxide.
4. The composition as claimed in claim 2 , wherein the glass frit has an average particle diameter (D 50 ) of 0.1 μm to 5 μm.
5. The composition as claimed in claim 2 , further comprising at least one additive selected from the group consisting of a dispersant, a thixotropic agent, a plasticizer, a viscosity stabilizer, an anti-foaming agent, a pigment, a UV stabilizer, an antioxidant, and a coupling agent.
6. A solar cell electrode prepared from the composition as claimed in claim 2 .
7. The glass fit as claimed in claim 1 , comprising 25 wt % to 48 wt % of tellurium oxide.
8. The glass frit as claimed in claim 1 , wherein the glass frit is a lead oxide-silicon oxide-tellurium oxide-bismuth oxide-zinc oxide glass frit.
9. The glass frit as claimed in claim 1 , wherein the glass frit is a lead oxide-tellurium oxide-bismuth oxide-zinc oxide-tungsten oxide glass fit.
10. The glass frit as claimed in claim 1 , wherein the glass fit is a lead oxide-silicon oxide-tellurium oxide-bismuth oxide-zinc oxide-tungsten oxide glass fit.
11. The glass frit as claimed in claim 1 , wherein the glass frit is a lead oxide-tellurium oxide-bismuth oxide-zinc oxide glass fit.