Aluminum-boron solar cell contacts

摘要

Formulations and methods of making solar cells are disclosed. In general, the invention provides a solar cell comprising a contact made from a mixture wherein, prior to firing, the mixture comprises at least one aluminum source, at least one boron source, and about 0.1 to about 10 wt % of a glass component. Within the mixture, the overall content of aluminum is about 50 wt % to about 85 wt % of the mixture, and the overall content of boron is about 0.05 to about 20 wt % of the mixture.

主权项

1. A solar cell comprising two separate layers, a silicon layer and a back contact layer deposited over a back surface of the silicon layer, wherein the back contact layer comprises a p+ layer with an active peak doping concentration of (Al+B) of about 1019 to about 1020 atoms per cubic centimeter, the back contact layer made from a mixture, wherein, prior to firing, the mixture comprises:
a. at least one aluminum source providing aluminum in an amount of about 50 wt % to about 85 wt % of the mixture, b. at least one boron source providing boron in an amount of about 0.25 wt % to about 20 wt % of the mixture, and c. about 0.1 to about 10 wt % of a glass component, including
(i) a first glass composition, wherein the first glass composition comprises
1. about 15 to about 75 mole % PbO and2. about 5 to about 50 mole % of (B2O3+SiO2), and(ii) a second glass composition comprising
3. about 30 to about 40 mole % (Li2O+Na2O+K2O),4. about 2 to about 26 mole % TiO2, and5. about 5 to about 75 mole % (B2O3+SiO2), wherein the first and second glass compositions are present in a weight ratio of about 5:1 to 1:5.