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) providing a substrate having a coating disposed thereon;
(b) selectively removing a portion of the coating with a laser;
(c) depositing a precursor composition onto the substrate, the precursor composition comprises at least one of metallic particles comprising a metal or a molecular precursor compound to the metal; and
(d) heating the precursor composition to form the solar cell conductive feature on the substrate, wherein the conductive feature has a feature width of not greater than 200 μm, a thickness of at least 1 μm, and a conductivity that is no less than 10 percent the conductivity of the equivalent pure metal.
2 . The process of claim 1 , wherein the depositing comprises syringe printing.
3 . The process of claim 1 , wherein the depositing comprises aerosol jet deposition.
4 . The process of claim 1 , wherein the depositing comprises ink jet printing.
5 . The process of claim 4 , wherein the depositing comprises directing droplets of the precursor composition toward a surface of the substrate, the droplets having an average droplet size not greater than about 10 μm.
6 . The process of claim 5 , wherein the average droplet size is not greater than about 5 μm.
7 . The process of claim 4 , wherein the conductive feature has a thickness of at least 5 μm.
8 . The process of claim 4 , wherein the width is not greater than about 100 μm.
9 . The process of claim 4 , wherein the width is not greater than about 75 μm.
10 . The process of claim 4 , wherein the width is not greater than about 50 μm.
11 . The process of claim 4 , wherein the heating comprises heating the precursor composition to a temperature not greater than 225° C. to form the solar cell conductive feature on the substrate.
12 . The process of claim 4 , wherein the heating comprises heating the precursor composition to a temperature not greater than 185° C. to form the solar cell conductive feature on the substrate.
13 . The process of claim 4 , wherein the substrate has a softening point of not greater than about 225° C.
14 . The process of claim 4 , wherein the substrate comprises a polymer.
15 . The process of claim 4 , wherein the substrate comprises a ceramic.
16 . 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.
17 . 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.
18 . The process of claim 1 , wherein the precursor composition comprises the metal precursor compound.
19 . The process of claim 18 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
20 . The process of claim 1 , wherein the precursor composition comprises the metallic particles.
21 . The process of claim 20 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
22 . 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.
23 . The process of claim 22 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
24 . The process of claim 22 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
25 . The process of claim 4 , wherein the conductive feature comprises a transparent conductive feature.
26 . The process of claim 4 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
27 . The process of claim 4 , wherein the precursor composition further comprises metal oxide particles.
28 . The process of claim 4 , wherein the precursor composition further comprises glass particles.
29 . 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.
30 . 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.
31 . The process of claim 30 , wherein the metallic particles comprise a cap or coating thereon.
32 . The process of claim 31 , wherein the cap or coating comprises an inorganic cap or coating.
33 . The process of claim 31 , wherein the cap or coating comprises silica.
34 . The process of claim 31 , wherein the cap or coating comprises glass.
35 . The process of claim 31 , wherein the cap or coating comprises an organic cap or coating.
36 . The process of claim 31 , wherein the cap or coating comprises a polymer.
37 . The process of claim 31 , 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.
38 . The process of claim 31 , wherein the cap or coating comprises PVP.
39 . The process of claim 4 , wherein the conductive feature comprises a metal-glass composition.
40 . The process of claim 4 , wherein the conductive feature is resistant to solder leaching.
41 . The process of claim 4 , wherein the process further comprises high shear mixing the precursor composition.
42 . The process of claim 4 , wherein the process further comprises surface modifying the substrate with a laser.
43 . A process for forming a solar cell conductive feature, comprising:
(a) depositing a precursor composition onto a substrate, the precursor composition comprising a metal precursor compound to the metal; and
(b) irradiating the precursor composition with light to limit spreading of the precursor composition on the surface and forming the solar cell conductive feature.
44 . The process of claim 43 , wherein the depositing comprises lithographic printing.
45 . The process of claim 43 , wherein the depositing comprises gravure printing.
46 . The process of claim 43 , wherein the depositing comprises flexo printing.
47 . The process of claim 43 , wherein the depositing comprises screen printing.
48 . The process of claim 43 , wherein the depositing comprises photopatteming printing.
49 . The process of claim 43 , wherein the depositing comprises drop on demand printing.
50 . The process of claim 43 , wherein the depositing comprises syringe printing.
51 . The process of claim 43 , wherein the depositing comprises aerosol jet deposition.
52 . The process of claim 43 , wherein the depositing comprises ink jet printing.
53 . The process of claim 52 , wherein the irradiating is simultaneous with the depositing.
54 . The process of claim 52 , wherein the light comprises UV light.
55 . The process of claim 54 , wherein the UV light photochemically decomposes the molecular precursor compound to the metal before spreading of the precursor composition.
56 . The process of claim 54 , wherein the depositing comprises directing droplets of the precursor composition toward a surface of the substrate, the droplets having an average droplet size not greater than about 10 μm.
57 . The process of claim 56 , wherein the average droplet size is not greater than about 5 μm.
58 . The process of claim 54 , wherein the conductive feature has a thickness of at least 1 μm.
59 . The process of claim 54 , wherein the conductive feature has a thickness of at least 5 μm.
60 . The process of claim 54 , wherein the conductive feature has a width not greater than about 100 μm.
61 . The process of claim 54 , wherein the conductive feature has a width not greater than about 75 μm.
62 . The process of claim 54 , wherein the conductive feature has a width not greater than about 50 μm.
63 . The process of claim 54 , wherein the heating comprises heating the precursor composition to a temperature not greater than 225° C. to form the solar cell conductive feature on the substrate.
64 . The process of claim 54 , wherein the heating comprises heating the precursor composition to a temperature not greater than 185° C. to form the solar cell conductive feature on the substrate.
65 . The process of claim 54 , wherein the substrate has a softening point of not greater than about 225° C.
66 . The process of claim 54 , wherein the substrate comprises a polymer.
67 . The process of claim 54 , wherein the substrate comprises a ceramic.
68 . The process of claim 54 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
69 . The process of claim 54 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
70 . The process of claim 54 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
71 . The process of claim 54 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
72 . The process of claim 71 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
73 . The process of claim 71 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
74 . The process of claim 54 , wherein the conductive feature comprises a transparent conductive feature.
75 . The process of claim 54 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
76 . The process of claim 54 , wherein the precursor composition further comprises metal oxide particles.
77 . The process of claim 54 , wherein the precursor composition further comprises glass particles.
78 . The process of claim 54 , wherein the precursor composition further comprises metallic nanoparticles having a volume median particle size of not greater than 100 nanometers.
79 . The process of claim 54 , wherein the precursor composition further comprises metallic particles having a volume median particle size of not greater than 0.3 μm.
80 . The process of claim 79 , wherein the metallic particles comprise a cap or coating thereon.
81 . The process of claim 80 , wherein the cap or coating comprises an inorganic cap or coating.
82 . The process of claim 80 , wherein the cap or coating comprises silica.
83 . The process of claim 80 , wherein the cap or coating comprises glass.
84 . The process of claim 80 , wherein the cap or coating comprises an organic cap or coating.
85 . The process of claim 80 , wherein the cap or coating comprises a polymer.
86 . The process of claim 80 , 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.
87 . The process of claim 80 , wherein the cap or coating comprises PVP.
88 . The process of claim 54 , wherein the conductive feature comprises a metal-glass composition.
89 . The process of claim 54 , wherein the conductive feature is resistant to solder leaching.
90 . The process of claim 54 , wherein the process further comprises high shear mixing the precursor composition.
91 . The process of claim 54 , wherein the process further comprises surface modifying the substrate with a laser.
92 . A process for forming a solar cell conductive feature, comprising:
(a) depositing a precursor composition onto a substrate, the precursor composition comprising at least one of metallic particles comprising a metal or a molecular precursor compound to the metal;
(b) confining the deposited precursor composition to a region on the substrate with a physical barrier; and
(c) heating the precursor composition to form the solar cell conductive feature on the substrate.
93 . The process of claim 92 , wherein the depositing comprises lithographic printing.
94 . The process of claim 92 , wherein the depositing comprises gravure printing.
95 . The process of claim 92 , wherein the depositing comprises flexo printing.
96 . The process of claim 92 , wherein the depositing comprises screen printing.
97 . The process of claim 92 , wherein the depositing comprises photopatterning printing.
98 . The process of claim 92 , wherein the depositing comprises drop on demand printing.
99 . The process of claim 92 , wherein the depositing comprises syringe printing.
100 . The process of claim 92 , wherein the depositing comprises aerosol jet deposition.
101 . The process of claim 92 , wherein the depositing comprises ink jet printing.
102 . The process of claim 101 , wherein the physical barrier comprises trenches.
103 . The process of claim 102 , wherein the trenches are formed by chemical etching or photochemical means.
104 . The process of claim 102 , wherein the trenches are formed through embossing, milling, grinding or scratching.
105 . The process of claim 102 , wherein the barrier is formed with a laser.
106 . The process of claim 102 , wherein the process further comprises the stpes of:
(d) forming a photoresist layer on the substrate; and
(e) forming the trenches in the photoresist layer.
107 . The process of claim 106 , wherein the trenches are formed in the photoresist layer with a laser.
108 . The process of claim 106 , wherein the trenches are formed in the photoresist layer through photolithography.
109 . The process of claim 101 , wherein the physical barrier comprises a feature having a porosity that retains the precursor composition by capillary forces.
110 . The process of claim 101 , wherein the physical barrier comprises retaining barriers.
111 . The process of claim 110 , wherein the retaining barriers are formed through a direct write printing process.
112 . The process of claim 110 , wherein the retaining barriers are formed through an ink jet printing process.
113 . The process of claim 112 , wherein the retaining barriers comprise two parallel lines with narrow parallel spacing, and wherein the precursor composition is direct printed between the two parallel lines to confine the precursor composition.
114 . The process of claim 101 , wherein the depositing comprises directing droplets of the precursor composition toward a surface of the substrate, the droplets having an average droplet size not greater than about 10 μm.
115 . The process of claim 114 , wherein the average droplet size is not greater than about 5 μm.
116 . The process of claim 101 , wherein the conductive feature has a thickness of at least 1 μm.
117 . The process of claim 101 , wherein the conductive feature has a thickness of at least 5 μm.
118 . The process of claim 101 , wherein the conductive feature has a width not greater than about 100 μm.
119 . The process of claim 101 , wherein the conductive feature has a width not greater than about 75 μm.
120 . The process of claim 101 , wherein the conductive feature has a width not greater than about 50 μm.
121 . The process of claim 101 , wherein the heating comprises heating the precursor composition to a temperature not greater than 225° C. to form the solar cell conductive feature on the substrate.
122 . The process of claim 101 , wherein the heating comprises heating the precursor composition to a temperature not greater than 185° C. to form the solar cell conductive feature on the substrate.
123 . The process of claim 101 , wherein the substrate has a softening point of not greater than about 225° C.
124 . The process of claim 101 , wherein the substrate comprises a polymer.
125 . The process of claim 101 , wherein the substrate comprises a ceramic.
126 . The process of claim 101 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
127 . The process of claim 101 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
128 . The process of claim 101 , wherein the precursor composition comprises the metal precursor compound.
129 . The process of claim 128 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
130 . The process of claim 101 , wherein the precursor composition comprises the metallic particles.
131 . The process of claim 130 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
132 . The process of claim 101 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
133 . The process of claim 132 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
134 . The process of claim 132 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
135 . The process of claim 101 , wherein the conductive feature comprises a transparent conductive feature.
136 . The process of claim 101 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
137 . The process of claim 101 , wherein the precursor composition further comprises metal oxide particles.
138 . The process of claim 101 , wherein the precursor composition further comprises glass particles.
139 . The process of claim 101 , wherein the precursor composition further comprises silver nanoparticles having a volume median particle size of not greater than 100 nanometers.
140 . The process of claim 101 , wherein the precursor composition further comprises silver particles having a volume median particle size of not greater than 0.3 μm.
141 . The process of claim 140 , wherein the silver particles comprise a cap or coating thereon.
142 . The process of claim 141 , wherein the cap or coating comprises an inorganic cap or coating.
143 . The process of claim 141 , wherein the cap or coating comprises silica.
144 . The process of claim 141 , wherein the cap or coating comprises glass.
145 . The process of claim 141 , wherein the cap or coating comprises an organic cap or coating.
146 . The process of claim 141 , wherein the cap or coating comprises a polymer.
147 . The process of claim 141 , 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.
148 . The process of claim 141 , wherein the cap or coating comprises PVP.
149 . The process of claim 101 , wherein the conductive feature comprises a metal-glass composition.
150 . The process of claim 101 , wherein the conductive feature is resistant to solder leaching.
151 . The process of claim 101 , wherein the process further comprises high shear mixing the precursor composition.
152 . A process for forming a solar cell conductive feature, comprising:
(a) depositing a precursor composition onto a surface modified substrate, the precursor composition comprises at least one of metallic particles comprising a metal or a molecular precursor compound to the metal; and
(b) heating the precursor composition to form the solar cell conductive feature on the surface modified substrate.
153 . The process of claim 152 , wherein the depositing comprises lithographic printing.
154 . The process of claim 152 , wherein the depositing comprises gravure printing.
155 . The process of claim 152 , wherein the depositing comprises flexo printing.
156 . The process of claim 152 , wherein the depositing comprises screen printing.
157 . The process of claim 152 , wherein the depositing comprises photopatterning printing.
158 . The process of claim 152 , wherein the depositing comprises drop on demand printing.
159 . The process of claim 152 , wherein the depositing comprises syringe printing.
160 . The process of claim 152 , wherein the depositing comprises aerosol jet deposition.
161 . The process of claim 152 , wherein the depositing comprises ink jet printing.
162 . The process of claim 161 , wherein the process further comprises:
(c) surface modifying the surface of an initial substrate to form the surface modified substrate.
163 . The process of claim 162 , wherein the surface modifying comprises surface modifying selected regions of the surface of the initial substrate.
164 . The process of claim 163 , wherein the surface modifying comprises surface energy patterning by increasing or decreasing the surface energy of the surface in the selected regions corresponding to where it is desired to confine the precursor composition.
165 . The process of claim 164 , wherein the surface modifying is performed with a laser.
166 . The process of claim 165 , wherein the laser removes hydroxyl groups from the surface.
167 . The process of claim 165 , wherein laser forms pores on the substrate.
168 . The process of claim 163 , wherein the surface modifying comprises surface energy patterning by increasing or decreasing the surface energy of the surface in the selected regions corresponding to where it is desired to eliminate the precursor composition.
169 . The process of claim 168 , wherein the surface modifying is performed with a laser.
170 . The process of claim 168 , wherein the laser removes hydroxyl groups from the surface.
171 . The process of claim 168 , wherein laser forms pores on the substrate.
172 . The process of claim 163 , wherein the surface modifying comprises increasing or decreasing the hydrophilicity of the substrate.
173 . The process of claim 163 , wherein the surface modifying increases adhesion of the precursor composition to the substrate.
174 . The process of claim 163 , wherein the surface modifying is performed with a thermal print head.
175 . The process of claim 163 , wherein the surface modifying comprises chemically modifying the surface.
176 . The process of claim 163 , wherein the surface modifying comprises electrostatic printing.
177 . The process of claim 163 , wherein the surface modifying comprises micro-contact printing.
178 . The process of claim 163 , wherein the substrate comprises glass, and wherein the surface modifying comprises increasing the surface energy of the glass in selected regions corresponding to where it is desired to confine or eliminate the precursor composition.
179 . The process of claim 163 , wherein the precursor composition has a surface tension of 20 to 50 dynes/cm.
180 . The process of claim 163 , wherein the depositing comprises directing droplets of the precursor composition toward a surface of the substrate, the droplets having an average droplet size not greater than about 10 μm.
181 . The process of claim 180 , wherein the average droplet size is not greater than about 5 μm.
182 . The process of claim 161 , wherein the conductive feature has a thickness of at least 1 μm.
183 . The process of claim 161 , wherein the conductive feature has a thickness of at least 5 μm.
184 . The process of claim 161 , wherein the conductive feature has a width not greater than about 100 μm.
185 . The process of claim 161 , wherein the conductive feature has a width not greater than about 75 μm.
186 . The process of claim 161 , wherein the conductive feature has a width not greater than about 50 μm.
187 . The process of claim 161 , wherein the heating comprises heating the precursor composition to a temperature not greater than 225° C. to form the solar cell conductive feature on the substrate.
188 . The process of claim 161 , wherein the heating comprises heating the precursor composition to a temperature not greater than 185° C. to form the solar cell conductive feature on the substrate.
189 . The process of claim 161 , wherein the substrate has a softening point of not greater than about 225° C.
190 . The process of claim 161 , wherein the substrate comprises glass.
191 . The process of claim 161 , wherein the substrate comprises a polymer.
192 . The process of claim 161 , wherein the substrate comprises a ceramic.
193 . The process of claim 161 , wherein the conductive feature has a resistivity that is not greater than 4 times the resistivity of the equivalent pure metal.
194 . The process of claim 161 , wherein the conductive feature has a resistivity that is not greater than 2 times the resistivity of the equivalent pure metal.
195 . The process of claim 161 , wherein the precursor composition comprises the metal precursor compound.
196 . The process of claim 195 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
197 . The process of claim 161 , wherein the precursor composition comprises the metallic particles.
198 . The process of claim 197 , wherein the metal is selected from the group consisting of silver, palladium, copper, gold, platinum and nickel.
199 . The process of claim 161 , wherein the conductive feature comprises a set of finger lines and collector lines deposited essentially at a right angle to the finger lines.
200 . The process of claim 199 , wherein either or both the parallel finger lines or the collector lines have width less than 200 μm.
201 . The process of claim 199 , wherein either or both the parallel finger lines or the collector lines have width less than 100 μm.
202 . The process of claim 161 , wherein the conductive feature comprises a transparent conductive feature.
203 . The process of claim 161 , wherein the conductive feature comprises indium-tin oxide or antimony-tin oxide.
204 . The process of claim 161 , wherein the precursor composition further comprises metal oxide particles.
205 . The process of claim 161 , wherein the precursor composition further comprises glass particles.
206 . The process of claim 161 , wherein the precursor composition further comprises silver nanoparticles having a volume median particle size of not greater than 100 nanometers.
207 . The process of claim 161 , wherein the precursor composition further comprises silver particles having a volume median particle size of not greater than 0.3 μm.
208 . The process of claim 207 , wherein the silver particles comprise a cap or coating thereon.
209 . The process of claim 208 , wherein the cap or coating comprises an inorganic cap or coating.
210 . The process of claim 208 , wherein the cap or coating comprises silica.
211 . The process of claim 208 , wherein the cap or coating comprises glass.
212 . The process of claim 208 , wherein the cap or coating comprises an organic cap or coating.
213 . The process of claim 208 , wherein the cap or coating comprises a polymer.
214 . The process of claim 208 , 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.
215 . The process of claim 208 , wherein the cap or coating comprises PVP.
216 . The process of claim 208 , wherein the conductive feature comprises a metal-glass composition.
217 . The process of claim 208 , wherein the conductive feature is resistant to solder leaching.
218 . The process of claim 208 , wherein the process further comprises high shear mixing the precursor composition.