Paste composition for solar cell electrode, electrode fabricated using the same, and solar cell including the same
A paste composition for solar cell electrodes includes conductive particles, a glass frit, an organic binder and a solvent. The conductive particles include at least two groups of conductive particle having different particle diameter distributions. The conductive particle may have an average particle diameter (D50′) of about 1.85 μm or less and a particle diameter (D90′) at 90% of the cumulative particle diameter distribution of about 3.10 μm or less.
1. A paste composition for a solar cell electrode, the paste composition comprising:
about 60˜90 wt % of conductive particles;
about 1˜15 wt % of a glass frit;
a total amount of about 5˜25 wt % of an organic binder; and
a solvent,
wherein:
the conductive particles include at least two groups of conductive particle having different particle diameter distributions,
the conductive particles have an average particle diameter (D50′) according to the following Equation 1 of about 1.85 μm or less and a particle diameter (D90′) at 90% of the cumulative particle diameter distribution according to the following Equation 2 of about 3.10 μm or less:
[
Equation
1
]
average
particle
diameter
(
D
50
′
)
=
(
X
1
*
Y
1
)
+
(
X
2
*
Y
2
)
+
…
+
(
Xn
*
Yn
)
X
1
+
X
2
+
…
+
Xn
[
Equation
2
]
particle
diameter
at
90
%
of
the
cumulative
particle
diameter
distribution
(
D
90
′
)
=
(
X
1
*
Z
1
)
+
(
X
2
*
Z
2
)
+
…
+
(
Xn
*
Zn
)
X
1
+
X
2
+
…
+
Xn
where,
X1: content of first conductive particle group (wt %);
X2: content of second conductive particle group (wt %);
Xn: content of an nth conductive particle group (wt %) when a number of the groups of conductive particle having different particle diameter distributions is greater than two, Xn being absent when the number of groups of the conductive particles is two;
Y1: D50 of first conductive particle group;
Y2: D50 of second conductive particle group;
Yn: D50 of the nth conductive particle group when the number of the groups of conductive particle having different particle diameter distributions is greater than two, Yn being absent when the number of groups of the conductive particles is two;
Z1: D90 of first conductive particle group;
Z2: D90 of second conductive particle group;
Zn: D90 of the nth conductive particle group when the number of the groups of conductive particle having different particle diameter distributions is greater than two, Zn being absent when the number of groups of the conductive particles is two; and
n: an integer of 3 or more when a number of the groups of conductive particle having different particle diameter distributions is greater than two; and wherein the paste composition has a scattering of efficiency of 0.15 or less in a sintering temperature range from about 900° C. to about 930° C.
2. The paste composition as claimed in claim 1 , wherein the conductive particles include at least one selected from the group of silver (Ag), gold (Au), palladium (Pd), platinum (Pt), copper (Cu), chromium (Cr), cobalt (Co), aluminum (Al), tin (Sn), lead (Pb), zinc (Zn), iron (Fe), iridium (Ir), osmium (Os), rhodium (Rh), tungsten (W), molybdenum (Mo), nickel (Ni), and indium tin oxide (ITO) particles.
3. The paste composition as claimed in claim 1 , wherein the conductive particles have an average particle diameter (D50′) of from about 1 μm to about 1.85 μm.
4. The paste composition as claimed in claim 1 , wherein the conductive particles have a particle diameter (D90′) of from about 1 μm to about 3.10 μm.
5. The paste composition as claimed in claim 1 , wherein:
the conductive particles include about 28˜32 parts by weight of a first conductive particle group, about 23˜25 parts by weight of a second conductive particle group, about 18˜22 parts by weight of a third conductive particle group, and about 8˜12 parts by weight of a fourth conductive particle group, based on 100 parts by weight of the paste composition,
the first conductive particle group has a particle diameter (D10) of about 0.9˜1.1 μm, a particle diameter (D50) of about 1.3˜1.5 μm, and a particle diameter (D90) of about 2.1˜2.3 μm,
the second conductive particle group has a particle diameter (D10) of about 0.3˜0.5 μm, a particle diameter (D50) of about 0.7˜0.9 μm, and a particle diameter (D90) of about 1.2˜1.4 μm,
the third conductive particle group has a particle diameter (D10) of about 1.5˜1.7 μm, a particle diameter (D50) of about 2.7˜2.9 μm, and a particle diameter (D90) of about 4.2˜4.4 μm, and
the fourth conductive particle group has a particle diameter (D10) of about 0.9-1.1 μm, a particle diameter (D50) of about 2.6˜2.8 μm, and a particle diameter (D90) of about 6.1˜6.3 μm.
6. The paste composition as claimed in claim 1 , further comprising at least one additive selected from the group 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.
7. An electrode formed of the paste composition as claimed in claim 1 .
8. A solar cell including the electrode as claimed in claim 7 .
9. A paste composition for a solar cell electrode, the paste composition comprising:
conductive particles; a glass frit; an organic binder; and a solvent; wherein:
the conductive particles include about 28˜32 parts by weight of a first conductive particle group, about 23˜25 parts by weight of a second conductive particle group, about 18˜22 parts by weight of a third conductive particle group, and about 8˜12 parts by weight of a fourth conductive particle group, based on 100 parts by weight of the paste composition, wherein:
the first conductive particle group has a particle diameter (D10) of about 0.9˜1.1 μm, a particle diameter (D50) of about 1.3˜1.5 μm, and a particle diameter (D90) of about 2.1˜2.3 μm,
the second conductive particle group has a particle diameter (D10) of about 0.3˜0.5 μm, a particle diameter (D50) of about 0.7˜0.9 μm, and a particle diameter (D90) of about 1.2˜1.4 μm,
the third conductive particle group has a particle diameter (D10) of about 1.5˜1.7 μm, a particle diameter (D50) of about 2.7˜2.9 μm, and a particle diameter (D90) of about 4.2˜4.4 μm, and
the fourth conductive particle group has a particle diameter (D10) of about 0.9˜1.1 μM, a particle diameter (D50) of about 2.6˜2.8 μm, and a particle diameter (D90) of about 6.1˜6.3 μm.