Solar cell

Abstract

A composition for solar cell electrodes, an electrode formed of the same, and a method of forming an electrode, the composition including a conductive powder; a glass frit; at least one of a cyclosiloxane compound and a silsesquioxane compound; and an organic vehicle.

1 .- 11 . (canceled) 
     
     
         12 . A solar cell including a front-side electrode prepared from a composition for solar cell electrodes, the composition including:
 a conductive powder;   a glass frit;   at least one of a cyclosiloxane compound and a silsesquioxane compound; and   an organic vehicle.   
     
     
         13 . The solar cell as claimed in  claim 12 , wherein the conductive powder does not include aluminum. 
     
     
         14 . The solar cell as claimed in  claim 12 , wherein the composition includes about 60 wt % to about 95 wt % of silver powder, based on a total weight of the composition. 
     
     
         15 . The solar cell as claimed in  claim 12 , wherein the at least one of the cyclosiloxane compound and silsesquioxane compound is present in an amount of about 0.1 wt % to about 2 wt % in the composition for solar cell electrodes. 
     
     
         16 . The solar cell as claimed in  claim 12 , wherein the composition has an area change rate of about 60% or less, as calculated according to the following Equation 1:
   Area change rate=(| S   1   −S   0   |/S   0 )×100  (1),
   wherein, in Equation 1,   S 0  denotes a cross-sectional area in μm 2  of an electrode formed by printing the composition for solar cell electrodes and not subjected to drying and baking, and   S 1  denotes a cross-sectional area in μm 2  of the electrode subjected to drying at 300° C. for 40 seconds and baking at 800° C. for 60 seconds.   
     
     
         17 . The solar cell as claimed in  claim 12 , wherein:
 the composition includes the cyclosiloxane compound, and   the cyclosiloxane compound includes hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane, octadecamethylcyclononasiloxane, tetramethylcyclotetrasiloxane, hexaphenylcyclotrisiloxane, tetramethyl-tetravinylcyclotetrasiloxane, tris(trifluoropropyl)-trimethylcyclotrisiloxane, hexadecamethylcyclooctasiloxane, pentamethylcyclopentasiloxane, hexamethylcyclohexasiloxane, octaphenylcyclotetrasiloxane, triphenylcyclotrisiloxane, tetraphenylcyclotetrasiloxane, tetramethyl-tetraphenylcyclotetrasiloxane, tetravinyl-tetraphenylcyclotetrasiloxane, hexamethyl-hexavinylcyclohexasiloxane, hexamethyl-hexaphenylcyclohexasiloxane, or hexavinyl-hexaphenylcyclohexasiloxane.   
     
     
         18 . The solar cell as claimed in  claim 12 , wherein:
 the composition includes the silsesquioxane compound, and   the silsesquioxane compound includes octaphenylsilsesquioxane, octamethylsilsesquioxane, or octavinylsilsesquioxane.   
     
     
         19 . The solar cell as claimed in  claim 12 , wherein the glass frit includes a bismuth-tellurium-oxide (Bi—Te—O)-based glass frit. 
     
     
         20 . The solar cell as claimed in  claim 19 , wherein the bismuth-tellurium-oxide (Bi—Te—O)-based glass frit further includes lithium (Li), zinc (Zn), phosphorus (P), germanium (Ge), gallium (Ga), cerium (Ce), iron (Fe), silicon (Si), tungsten (W), magnesium (Mg), cesium (Cs), strontium (Sr), molybdenum (Mo), titanium (Ti), tin (Sn), indium (In), vanadium (V), barium (Ba), nickel (Ni), copper (Cu), sodium (Na), potassium (K), arsenic (As), cobalt (Co), zirconium (Zr), or manganese (Mn). 
     
     
         21 . The solar cell as claimed in  claim 12 , wherein the composition includes:
 about 60 wt % to about 95 wt % of the conductive powder;   about 0.1 wt % to 2 wt % of the at least one of the cyclosiloxane compound and silsesquioxane compound;   about 0.1 wt % to about 20 wt % of the glass frit; and   about 1 wt % to about 30 wt % of the organic vehicle, all wt % being based on a total weight of the composition.   
     
     
         22 . The solar cell as claimed in  claim 12 , wherein the composition further includes a dispersant, a thixotropic agent, a plasticizer, a viscosity stabilizer, an anti-foaming agent, a pigment, a UV stabilizer, an antioxidant, or a coupling agent.