Composition for forming electrode, electrode manufactured using the same and solar cell

1. A composition for forming an electrode for a solar cell, comprising:

a conductive powder, a glass fit, and an organic binder, the organic binder including a cellulose compound that includes a structural unit represented by Chemical Formula 1:

wherein, in Chemical Formula 1,

R 1 , R 2 , and R 3 are independently hydrogen, a substituted or unsubstituted C1 to C15 alkyl group, a substituted or unsubstituted C2 to C15 alkenyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C3 to C20 heterocycloalkyl group, a substituted or unsubstituted C3 to C20 aryl group, a substituted or unsubstituted C3 to C20 heteroaryl group, or a functional group represented by Chemical Formula 2,

provided that at least one of R 1 , R 2 , and R 3 includes a functional group represented by Chemical Formula 2,

wherein, in Chemical Formula 2,

R 4 to R 7 are independently hydrogen, a hydroxy group, or a substituted or unsubstituted C1 to C15 alkyl group, or R 5 and R 7 are linked with each other to form a fused ring,

X is oxygen or sulfur,

L 1 is a substituted or unsubstituted C1 to C15 alkylene group,

n1 to n5 are independently 0 or 1, provided that n1 to n5 are not simultaneously 0, and provided that, when n4 is 1, one or more of n1 to n3 is 1, and

R 8 is represented by Chemical Formula 3-2,

wherein, in Chemical Formula 3-2,

R 9 to R 13 are independently a substituted or unsubstituted C1 to C15 alkyl group, and

m is an integer ranging from 1 to 100.

2. The composition as claimed in claim 1 , wherein the cellulose compound has a weight average molecular weight of about 5,000 g/mol to about 200,000 g/mol.

3. The composition as claimed in claim 1 , wherein the composition includes about 60 wt % to about 95 wt % of the conductive powder; about 0.5 wt % to about 20 wt % of the glass fit; about 0.1 wt % to about 20 wt % of the organic binder; and a solvent.

4. The composition as claimed in claim 1 , wherein the glass fit includes one or more of lead, tellurium, bismuth, lithium, phosphorus, germanium, gallium, cerium, iron, silicon, zinc, tungsten, magnesium, cesium, strontium, molybdenum, titanium, tin, indium, vanadium, barium, nickel, copper, sodium, potassium, arsenic, cobalt, zirconium, manganese, or aluminum.

5. The composition as claimed in claim 1 , wherein the solvent includes one or more of methyl cellosolve, ethyl cellosolve, butyl cellosolve, aliphatic alcohol, α-terpineol, β-terpineol, dihydro-terpineol, ethylene glycol, ethylene glycol mono butyl ether, butyl cellosolve acetate, or 2,2,4-trimethyl-1,3-pentanediol isobutyrate.

6. The composition as claimed in claim 1 , further comprising one or more of a surface-treatment agent, a dispersing agent, thixotropic agent, a viscosity stabilizer, a plasticizer, an antifoaming agent, a pigment, an ultraviolet stabilizer, an antioxidant, or a coupling agent.

7. A solar cell electrode manufactured using the composition as claimed in claim 1 .

8. A solar cell comprising the electrode as claimed in claim 7 .

9. The solar cell as claimed in claim 8 , wherein the solar cell has a passivated emitter and rear cell structure.

10. The composition as claimed in claim 1 , wherein, in Chemical Formula 2,

n1, n2, n4, and n5 are each 1,

n3 is 0, and

R 4 is a hydroxy group.

11. The composition as claimed in claim 1 , wherein, in Chemical Formula 2,

n1, n2, n4, and n5 are each 1,

n3 is 0,

R 4 is a hydroxy group, and

R 5 and R 7 are linked with each other to form a C3 to C10 cycloalkane.

12. The composition as claimed in claim 1 , wherein, in Chemical Formula 2,

n2, n3, n4, and n5 are each 1,

n1 is 0, and

R 6 is a substituted or unsubstituted C1 to C15 alkyl group.

13. The composition as claimed in claim 1 , wherein, in Chemical Formula 2,

n3 and n5 are each 1, and

n1, n2, and n4 are each 0.

14. The composition as claimed in claim 1 , wherein the functional group represented by Chemical Formula 2 is represented by one of Chemical Formula 2-1 to Chemical Formula 2-4:

wherein, in Chemical Formula 2-1 to Chemical Formula 2-4,

L 1 is a substituted or unsubstituted C1 to C15 alkylene group, and

R 8 is represented by Chemical Formula

wherein, in Chemical Formula 3-2,

R 9 to R 13 are independently a substituted or unsubstituted C1 to C15 alkyl group, and

m is an integer ranging from 1 to 100.