Organometallic and hydrocarbon additives for use with aluminum back solar cell contacts

Patent metadata

Field	Value
Publication number	US-9680036-B2
Application number	US-201213342231-A
Country	US
Kind code	B2
Filing date	Jan 3, 2012
Priority date	Jan 6, 2011
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

A method of reducing bow and/or improving the electrical performance of an aluminum back contacted silicon solar cell includes applying to a silicon wafer substrate a paste including aluminum and an organometallic compound, and firing the substrate. The organometallic compound is a C 1 to C 30 organometallic compound of a metal selected from the group consisting of Ag, Al, Ba, Bi, Ca, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Nd, Ni, Sb, Si, Sn, Sr, Ta, V, Zn, Zr. A paste is formed having an exothermic reaction peak at a temperature of at least 300° C. to less than 660° C.

First claim

The invention claimed is:

1. A method of forming an aluminum back contacted silicon solar cell having at least one of reduced bow and improved electrical performance, comprising:
a. providing a silicon wafer substrate,
b. providing a paste comprising:
i. aluminum,
ii. a glass fit, and
iii. an organometallic compound, wherein the organometallic compound is an organic compound of a metal selected from the group consisting of cobalt, manganese, nickel, iron, silicon, tin, antimony, bismuth, vanadium, strontium and combinations thereof,

c. applying the paste to the silicon wafer substrate to form a coated substrate, and
d. firing the coated substrate for a time and at a temperature sufficient to sinter the aluminum together with the organometallic compound and fuse the glass frit.

2. The method of claim 1 , wherein the organometallic compound is provided in the form of a compound having from 1 to 6 hydrocarbon residues, the residues independently having from 1 to 30 carbon atoms.

3. The method of claim 1 , wherein the glass frit comprises
a. 15-55 mol % Bi 2 O 3 ,
b. 15-55 mol % SiO 2 ,
c. 1-15 mol % B 2 O 3 , and
d. 5-35 mol % (Li 2 O+Na 2 O+K 2 O).

4. The method of claim 1 , wherein the glass frit comprises:
a. 20-55 mol % Bi 2 O 3 ,
b. 10-35 mol % K 2 O,
c. 1-10 mol % B 2 O 3 and
d. 10-50 mol % SiO 2 .

5. The method of claim 1 , wherein the glass frit comprises:
a. 10-25 mol % B 2 O 3 ,
b. 0.5-3 mol % K 2 O,
c. 0.01-3 mol % Na 2 O, and
d. 70-90 mol % SiO 2 .

6. The method of claim 1 , wherein the glass frit comprises:
a. 5-15 mol % K 2 O,
b. 1-8 mol % Li 2 O,
c. 16-28 mol % Na 2 O,
d. 0.2-8 mol % P 2 O 5 ,
e. 30-50 mol % SiO 2 ,
f. 15-35 mol % TiO 2 , and
g. 1-16 mol % V 2 O 5 .

7. The method of claim 1 , wherein a sufficient amount of the organometallic compound is present in order to provide 100 ppmw to 10 wt % of the metal.

8. The method of claim 1 , wherein a sufficient amount of the organometallic compound is present in order to provide 500 ppmw to 8 wt % of the metal.

9. The method of claim 1 , wherein a sufficient amount of the organometallic compound is present in order to provide 1000 ppmw to 7 wt % of the metal.

10. The method of claim 1 , wherein a sufficient amount of the organometallic compound is present in order to provide 0.05 wt % to 5 wt % of the metal.

11. The method of claim 1 , wherein the aluminum metal is present in a proportion of 40-80 wt % of the entire paste.

Assignees

• Merchant Nazarali
• Shaikh Aziz S
• Khadilkar Chandrashekhar S
• Sridharan Srinivasan
• Jiang Hong
• Heraeus Precious Metals North America Conshohocken Llc

Inventors

• Merchant Nazarali
• Shaikh Aziz S
• Khadilkar Chandrashekhar S
• Sridharan Srinivasan
• Jiang Hong

Classifications

• H10F71/00

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• H01L31/022425 Primary

  Electricity · mapped topic

• H01L31/18

  Electricity · mapped topic

• H10F77/211 Primary

  for photovoltaic cells · CPC title