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 photovoltaic conductive feature, the process comprising the steps of:
(a) providing a precursor composition comprising a liquid vehicle and at least one of metallic particles comprising a metal or a metal precursor compound to the metal;
(b) depositing the precursor composition onto a substrate; and
(c) treating the printed precursor composition with laser radiation to convert the precursor composition to the photovoltaic conductive feature.
2 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in a lithographic printing process.
3 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in a gravure printing process.
4 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in a flexo printing process.
5 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in a screen printing process.
6 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in an photopatterning printing process.
7 . The process of claim 1 , wherein the precursor composition is deposited on the substrate by a drop on demand printing process.
8 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in an ink jet printing process.
9 . The process of claim 1 , wherein the laser radiation comprises IR laser radiation.
10 . The process of claim 1 , wherein the laser radiation comprises UV laser radiation.
11 . The process of claim 1 , wherein the laser radiation comprises pulsed or continuous wave laser radiation.
12 . The process of claim 1 , wherein the laser radiation comprises scanning laser radiation.
13 . The process of claim 1 , wherein the precursor composition comprises metal oxide particles.
14 . The process of claim 1 , wherein the precursor composition comprises glass particles.
15 . The process of claim 1 , wherein the precursor composition comprises the metallic particles.
16 . The process of claim 15 , wherein the metal in the metallic particles is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
17 . The process of claim 15 , wherein the treating sinters the metallic particles.
18 . The process of claim 15 , wherein the conductivity of the conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
19 . The process of claim 15 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
20 . The process of claim 15 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
21 . The process of claim 15 , wherein the laser provides a sintering time of not greater than 1 second.
22 . The process of claim 15 , wherein the laser provides a sintering time of not greater than 0.1 second.
23 . The process of claim 15 , wherein the laser provides a sintering time of not greater than 0.01 second.
24 . The process of claim 15 , wherein the metallic particles have a volume median particle size of not greater than 100 nanometers.
25 . The process of claim 15 , wherein the metallic particles have a volume median particle size of not greater than 0.3 μm.
26 . The process of claim 25 , wherein the metallic particles comprise a cap or coating thereon.
27 . The process of claim 26 , wherein the cap or coating comprises an inorganic cap or coating.
28 . The process of claim 26 , wherein the cap or coating comprises silica.
29 . The process of claim 26 , wherein the cap or coating comprises glass.
30 . The process of claim 26 , wherein the cap or coating comprises an organic cap or coating.
31 . The process of claim 26 , wherein the cap or coating comprises a polymer.
32 . The process of claim 26 , 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.
33 . The process of claim 26 , wherein the cap or coating comprises PVP.
34 . The process of claim 25 , wherein at least 80 volume percent of the metallic particles are not larger than twice the average particle size.
35 . The process of claim 8 , wherein the precursor composition comprises the metal precursor compound to the metal.
36 . The process of claim 35 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
37 . The process of claim 35 , wherein the treating sinters the metal formed from the metal precursor compound.
38 . The process of claim 35 , wherein the conductivity of the conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
39 . The process of claim 35 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
40 . The process of claim 35 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
41 . The process of claim 8 , wherein the precursor composition comprises the metallic particles and the metal precursor compound to a metal.
42 . The process of claim 41 , wherein the metallic particles comprise a second metal different from the metal formed from the metal precursor compound.
43 . The process of claim 41 , wherein the metallic particles comprise the same metal as the metal formed from the metal precursor compound.
44 . The process of claim 8 , wherein the precursor composition has a viscosity not greater than about 1000 centipoise.
45 . The process of claim 8 , wherein the precursor composition has a viscosity not greater than about 100 centipoise.
46 . The process of claim 8 , wherein the precursor composition has a viscosity not greater than about 50 centipoise.
47 . The process of claim 8 , wherein the substrate comprises a ceramic.
48 . The process of claim 8 , wherein the substrate comprises a polymer.
49 . The process of claim 8 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
50 . The process of claim 49 , wherein either or both the parallel finger lines or the collector lines have a width not greater than 200 μm.
51 . The process of claim 49 , wherein either or both the parallel finger lines or the collector lines have a width not greater than 100 μm.
52 . The process of claim 8 , wherein the conductive feature has a thickness greater than 5 μm.
53 . The process of claim 8 , wherein the conductive feature comprises a transparent conductive feature.
54 . The process of claim 8 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
55 . The process of claim 8 , wherein the conductive feature comprises a metal-glass composition.
56 . The process of claim 8 , wherein the conductive feature is resistant to solder leaching.
57 . The process of claim 8 , wherein the process further comprises high shear mixing the precursor composition.
58 . The process of claim 8 , wherein the process further comprises surface modifying the substrate with a laser.
59 . A process for forming a photovoltaic conductive feature disposed on a substrate, comprising treating an ink jet printed precursor composition with laser radiation to convert the precursor composition to the photovoltaic conductive feature.
60 . The process of claim 59 , wherein the laser radiation comprises IR laser radiation.
61 . The process of claim 59 , wherein the laser radiation comprises UV laser radiation.
62 . The process of claim 59 , wherein the laser radiation comprises pulsed or continuous wave laser radiation.
63 . The process of claim 59 , wherein the laser radiation comprises scanning laser radiation.
64 . The process of claim 59 , wherein the precursor composition comprises metal oxide particles.
65 . The process of claim 59 , wherein the precursor composition comprises glass particles.
66 . The process of claim 59 , wherein the precursor composition comprises metallic particles comprising a metal.
67 . The process of claim 66 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
68 . The process of claim 66 , wherein the treating sinters the metallic particles.
69 . The process of claim 66 , wherein the conductivity of the conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
70 . The process of claim 66 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
71 . The process of claim 66 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
72 . The process of claim 66 , wherein the laser provides a sintering time of not greater than 1 second.
73 . The process of claim 66 , wherein the laser provides a sintering time of not greater than 0.1 second.
74 . The process of claim 66 , wherein the laser provides a sintering time of not greater than 0.01 second.
75 . The process of claim 66 , wherein the metallic particles have a volume median particle size of not greater than 100 nanometers.
76 . The process of claim 66 , wherein the metallic particles have a volume median particle size of not greater than 0.3 μm.
77 . The process of claim 76 , wherein the metallic particles comprise a cap or coating thereon.
78 . The process of claim 77 , wherein the cap or coating comprises an inorganic cap or coating.
79 . The process of claim 77 , wherein the cap or coating comprises silica.
80 . The process of claim 77 , wherein the cap or coating comprises glass.
81 . The process of claim 77 , wherein the cap or coating comprises an organic cap or coating.
82 . The process of claim 77 , wherein the cap or coating comprises a polymer.
83 . The process of claim 77 , 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.
84 . The process of claim 77 , wherein the cap or coating comprises PVP.
85 . The process of claim 76 , wherein at least 80 volume percent of the metallic particles are not larger than twice the average particle size.
86 . The process of claim 59 , wherein the precursor composition comprises a metal precursor compound to a metal.
87 . The process of claim 86 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
88 . The process of claim 87 , wherein the treating sinters the metal formed from the metal precursor compound.
89 . The process of claim 87 , wherein the conductivity of the conductive feature is no less than 10 percent the conductivity of the equivalent pure metal.
90 . The process of claim 87 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
91 . The process of claim 87 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
92 . The process of claim 59 , wherein the precursor composition comprises metallic particles and a metal precursor compound to a metal.
93 . The process of claim 92 , wherein the metallic particles comprise a second metal different from the metal formed from the metal precursor compound.
94 . The process of claim 92 , wherein the metallic particles comprise the same metal as the metal formed from the metal precursor compound.
95 . The process of claim 59 , wherein the precursor composition has a viscosity not greater than about 1000 centipoise.
96 . The process of claim 59 , wherein the precursor composition has a viscosity not greater than about 100 centipoise.
97 . The process of claim 59 , wherein the precursor composition has a viscosity not greater than about 50 centipoise.
98 . The process of claim 59 , wherein the substrate comprises a ceramic.
99 . The process of claim 59 , wherein the substrate comprises a polymer.
100 . The process of claim 59 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
101 . The process of claim 100 , wherein either or both the parallel finger lines or the collector lines have a width not greater than 200 μm.
102 . The process of claim 100 , wherein either or both the parallel finger lines or the collector lines have a width not greater than 100 μm.
103 . The process of claim 59 , wherein the conductive feature has a thickness greater than 5 μm.
104 . The process of claim 59 , wherein the conductive feature comprises a transparent conductive feature.
105 . The process of claim 59 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
106 . The process of claim 59 , wherein the conductive feature comprises a metal-glass composition.
107 . The process of claim 59 , wherein the conductive feature is resistant to solder leaching.
108 . The process of claim 59 , wherein the process further comprises high shear mixing the precursor composition.
109 . The process of claim 59 , wherein the process further comprises surface modifying the substrate with a laser.
110 . The process of claim 1 , wherein the photovoltaic conductive feature comprises a solar cell conductive feature.
111 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in an electrostatic printing process.
112 . The process of claim 1 , wherein the precursor composition is deposited on the substrate in a non-contact printing process.
113 . The process of claim 59 , wherein the photovoltaic conductive feature comprises a solar cell conductive feature.