Low viscosity precursor compositions and methods for the deposition of conductive electronic features
A precursor composition for the deposition and formation of an electrical feature such as a conductive feature. The precursor composition advantageously has a low viscosity enabling deposition using direct-write tools. The precursor composition also has a low conversion temperature, enabling the deposition and conversion to an electrical feature on low temperature substrates. A particularly preferred precursor composition includes silver metal for the formation of highly conductive silver features.
1 . A process for forming a solar cell conductive feature, comprising:
(a) direct printing a precursor composition onto a substrate, the precursor composition comprising at least one of metallic particles comprising a metal or a metal precursor compound to the metal; and
(b) heating the composition to a temperature not greater than 300° C. to form the solar cell conductive feature on the substrate, wherein the conductivity of the solar cell conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
2 . The process of claim 1 , wherein the direct printing comprises syringe printing.
3 . The process of claim 1 , wherein the direct printing comprises aerosol jet deposition.
4 . The process of claim 1 , wherein the direct printing comprises ink jet printing.
5 . The process of claim 4 , whereint the temperature is not greater than 250° C.
6 . The process of claim 4 , wherein the temperature is not greater than 185° C.
7 . The process of claim 4 , wherein the substrate comprises a polymer.
8 . The process of claim 4 , wherein the substrate has a softening point of not greater than 225° C.
9 . The process of claim 1 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
10 . The process of claim 1 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
11 . The process of claim 1 , wherein the precursor composition comprises the metallic particles, and wherein the heating sinters adjacent metallic particles to one another.
12 . The process of claim 11 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
13 . The process of claim 1 , wherein the precursor composition comprises the metal precursor compound.
14 . The process of claim 13 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
15 . The process of claim 1 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
16 . The process of claim 15 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
17 . The process of claim 15 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
18 . The process of claim 1 , wherein the conductive feature has a thickness greater than 5 μm.
19 . The process of claim 1 , wherein the conductive feature comprises a transparent conductive feature.
20 . The process of claim 1 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
21 . The process of claim 1 , wherein the precursor composition comprises the metallic particles, the metallic particles having a volume median particle size of not greater than 100 nanometers.
22 . The process of claim 1 , wherein the precursor composition comprises the metallic particles, the metallic particles having a volume median particle size of not greater than 0.3 μm.
23 . The process of claim 22 , wherein the metallic particles comprise a cap or coating thereon.
24 . The process of claim 23 , wherein the cap or coating comprises an inorganic cap or coating.
25 . The process of claim 23 , wherein the cap or coating comprises silica.
26 . The process of claim 23 , wherein the cap or coating comprises an organic cap or coating.
27 . The process of claim 23 , wherein the cap or coating comprises a polymer.
28 . The process of claim 23 , wherein the cap or coating comprises an intrinsically conductive polymer, a sulfonated perfluorohydrocarbon polymer, polystyrene, polystyrene/methacrylate, sodium bis(2-ethylhexyl) sulfosuccinate, tetra-n-octyl-ammonium bromide or an alkane thiolate.
29 . The process of claim 23 , wherein the cap or coating comprises PVP.
30 . The process of claim 1 , wherein the conductive feature is resistant to solder leaching.
31 . The process of claim 1 , wherein the process further comprises surface modifying the substrate with a laser.
32 . A process for forming a solar cell conductive feature, the process comprising heating an ink jet printed precursor composition comprising a metal to a temperature not greater than 300° C. to form the solar cell conductive feature on a substrate, wherein the conductivity of the solar cell conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
33 . The process of claim 32 , wherein the precursor composition comprises at least one of metallic particles comprising the metal or a metal precursor compound to the metal.
34 . The process of claim 33 , wherein the temperature is not greater than 250° C.
35 . The process of claim 33 , wherein the temperature is not greater than 185° C.
36 . The process of claim 33 , wherein the substrate comprises a polymer.
37 . The process of claim 33 , wherein the substrate has a softening point of not greater than 225° C.
38 . The process of claim 33 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
39 . The process of claim 33 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
40 . The process of claim 33 , wherein the precursor composition comprises the metallic particles, and wherein the heating sinters adjacent metallic particles to one another.
41 . The process of claim 40 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
42 . The process of claim 33 , wherein the precursor composition comprises the metal precursor compound.
43 . The process of claim 42 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
44 . The process of claim 33 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
45 . The process of claim 44 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
46 . The process of claim 44 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
47 . The process of claim 33 , wherein the conductive feature has a thickness greater than 5 μm.
48 . The process of claim 33 , wherein the conductive feature comprises a transparent conductive feature.
49 . The process of claim 33 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
50 . The process of claim 33 , wherein the precursor composition comprises metallic particles, the metallic particles having a volume median particle size of not greater than 100 nanometers.
51 . The process of claim 33 , wherein the precursor composition comprises metallic particles, the metallic particles having a volume median particle size of not greater than 0.3 μm.
52 . The process of claim 51 , wherein the metallic particles comprise a cap or coating thereon.
53 . The process of claim 52 , wherein the cap or coating comprises an inorganic cap or coating.
54 . The process of claim 52 , wherein the cap or coating comprises silica.
55 . The process of claim 52 , wherein the cap or coating comprises an organic cap or coating.
56 . The process of claim 52 , wherein the cap or coating comprises a polymer.
57 . The process of claim 52 , wherein the cap or coating comprises an intrinsically conductive polymer, a sulfonated perfluorohydrocarbon polymer, polystyrene, polystyrene/methacrylate, sodium bis(2-ethylhexyl) sulfosuccinate, tetra-n-octyl-ammonium bromide or an alkane thiolate.
58 . The process of claim 52 , wherein the cap or coating comprises PVP.
59 . The process of claim 33 , wherein the conductive feature is resistant to solder leaching.
60 . The process of claim 33 , wherein the process further comprises surface modifying the substrate with a laser.