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 precursor composition for a hold time of not greater than 60 seconds to form the solar cell conductive feature on the substrate.
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 , wherein the hold time is not greater than 30 seconds.
6 . The process of claim 4 , wherein the hold time is not greater than 0.1 second
7 . The process of claim 4 , wherein the precursor composition comprises the metal precursor compound to the metal, and wherein the metal precursor compound is reacted with a total reaction time of not greater than about 10 seconds.
8 . The process of claim 4 , wherein the precursor composition comprises the metal precursor compound to the metal, and wherein the metal precursor compound is reacted with a total reaction time of not greater than about 1 seconds.
9 . The process of claim 4 , wherein the precursor composition comprises the metal precursor compound to the metal.
10 . The process of claim 9 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
11 . The process of claim 4 , wherein the conductive feature has a thickness greater than 1 μm.
12 . The process of claim 4 , wherein the conductive feature has a thickness greater than 5 μm.
13 . The process of claim 4 , wherein the heating comprises heating the precursor composition to a temperature not greater than 300° C.
14 . The process of claim 4 , wherein the heating comprises heating the precursor composition to a temperature not greater than 225° C.
15 . The process of claim 4 , wherein the heating comprises heating the precursor composition to a temperature not greater than 185° C.
16 . The process of claim 4 , wherein the substrate has a softening point of not greater than about 225° C.
17 . The process of claim 4 , wherein the substrate comprises a polymer.
18 . The process of claim 4 , wherein the substrate comprises a ceramic.
19 . The process of claim 4 , wherein the conductivity of the conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
20 . The process of claim 4 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
21 . The process of claim 4 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
22 . The process of claim 4 , wherein the precursor composition comprises the metallic particles comprising the metal.
23 . The process of claim 22 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
24 . The process of claim 4 , wherein the precursor composition further comprises metal oxide particles.
25 . The process of claim 4 , wherein the precursor composition further comprises glass particles.
26 . The process of claim 4 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
27 . The process of claim 26 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
28 . The process of claim 26 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
29 . The process of claim 4 , wherein the conductive feature comprises a transparent conductive feature.
30 . The process of claim 4 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
31 . The process of claim 4 , wherein the precursor composition comprises the metallic particles, the metallic particles having a volume median particle size of not greater than 100 nanometers.
32 . The process of claim 4 , wherein the precursor composition comprises the metallic particles, the metallic particles having a volume median particle size of not greater than 0.3 μm.
33 . The process of claim 32 , wherein the metallic particles comprise a cap or coating thereon.
34 . The process of claim 33 , wherein the cap or coating comprises an inorganic cap or coating.
35 . The process of claim 33 , wherein the cap or coating comprises silica.
36 . The process of claim 33 , wherein the cap or coating comprises glass.
37 . The process of claim 33 , wherein the cap or coating comprises an organic cap or coating.
38 . The process of claim 33 , wherein the cap or coating comprises a polymer.
39 . The process of claim 33 , 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.
40 . The process of claim 33 , wherein the cap or coating comprises PVP.
41 . The process of claim 4 , wherein the conductive feature comprises a metal-glass composition.
42 . The process of claim 4 , wherein the conductive feature is resistant to solder leaching.
43 . The process of claim 4 , wherein the process further comprises high shear mixing the precursor composition.
44 . The process of claim 4 , wherein the ink jet printing comprises depositing droplets of the precursor composition onto the substrate at a rate of 1000 drops per second or higher.
45 . The process of claim 4 , wherein the process further comprises surface modifying the substrate with a laser.
46 . A process for forming a solar cell conductive feature, comprising heating an ink jet printed precursor composition on a substrate for a hold time less than 60 seconds to form the solar cell conductive feature on the substrate.
47 . The process of claim 46 , wherein the hold time is not greater than 30 seconds.
48 . The process of claim 46 , wherein the hold time is not greater than 0.1 second
49 . The process of claim 46 , wherein the precursor composition comprises a metal precursor compound to a metal, and wherein the metal precursor compound is reacted with a total reaction time of not greater than about 10 seconds.
50 . The process of claim 46 , wherein the precursor composition comprises a metal precursor compound to a metal, and wherein the metal precursor compound is reacted with a total reaction time of not greater than about 1 seconds.
51 . The process of claim 46 , wherein the conductive feature has a thickness greater than 1 μm.
52 . The process of claim 46 , wherein the conductive feature has a thickness greater than 5 μm.
53 . The process of claim 46 , wherein the heating comprises heating the precursor composition to a temperature not greater than 300° C.
54 . The process of claim 46 , wherein the heating comprises heating the precursor composition to a temperature not greater than 225° C.
55 . The process of claim 46 , wherein the heating comprises heating the precursor composition to a temperature not greater than 185° C.
56 . The process of claim 46 , wherein the substrate has a softening point of not greater than about 225° C.
57 . The process of claim 46 , wherein the substrate comprises a polymer.
58 . The process of claim 46 , wherein the substrate comprises a ceramic.
59 . The process of claim 46 , wherein the precursor composition comprises a metal, and wherein the conductivity of the conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
60 . The process of claim 46 , wherein the precursor composition comprises a metal, and wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
61 . The process of claim 46 , wherein the precursor composition comprises a metal, and wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
62 . The process of claim 46 , wherein the precursor composition comprises a metal precursor compound to a metal.
63 . The process of claim 62 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
64 . The process of claim 46 , wherein the precursor composition comprises metallic particles comprising a metal.
65 . The process of claim 64 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
66 . The process of claim 46 , wherein the precursor composition comprises metal oxide particles.
67 . The process of claim 46 , wherein the precursor composition comprises glass particles.
68 . The process of claim 46 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
69 . The process of claim 68 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
70 . The process of claim 68 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
71 . The process of claim 46 , wherein the conductive feature comprises a transparent conductive feature.
72 . The process of claim 46 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
73 . The process of claim 46 , wherein the precursor composition comprises metallic particles, the metallic particles having a volume median particle size of not greater than 100 nanometers.
74 . The process of claim 46 , wherein the precursor composition comprises metallic particles, the metallic particles having a volume median particle size of not greater than 0.3 μm.
75 . The process of claim 74 , wherein the metallic particles comprise a cap or coating thereon.
76 . The process of claim 75 , wherein the cap or coating comprises an inorganic cap or coating.
77 . The process of claim 75 , wherein the cap or coating comprises silica.
78 . The process of claim 75 , wherein the cap or coating comprises glass.
79 . The process of claim 75 , wherein the cap or coating comprises an organic cap or coating.
80 . The process of claim 75 , wherein the cap or coating comprises a polymer.
81 . The process of claim 75 , 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.
82 . The process of claim 75 , wherein the cap or coating comprises PVP.
83 . The process of claim 46 , wherein the conductive feature comprises a metal-glass composition.
84 . The process of claim 46 , wherein the conductive feature is resistant to solder leaching.
85 . The process of claim 46 , wherein the process further comprises high shear mixing the precursor composition.
86 . The process of claim 46 , wherein the ink jet printing comprises depositing droplets of the precursor composition onto the substrate at a rate of 1000 drops per second or higher.
87 . The process of claim 46 , wherein the process further comprises surface modifying the substrate with a laser.