Patent ID: 8778231

Claim:
A process of forming a silicon solar cell comprising (a) providing an aluminum paste composition consisting essentially of; i. 0.003% to 9% by weight of boron nitride; ii. 27% to 89%, by weight of an aluminum powder, such that the weight ratio of aluminum powder to boron nitride is in the range of 9:1 to 9909:1; iii. 0.1% to 9%, by weight of an optional glass frit-free additive wherein the optional glass frit-free additive comprises amorphous silicon dioxide, crystalline calcium oxide, organometallic compounds, metal salts, or mixtures thereof; and iv. 10% to 70%, by weight of an organic vehicle, wherein the organic vehicle comprises an organic solvent and an organic polymer, wherein the aluminum paste composition excludes a glass frit, and wherein the amounts in % by weight are based on the total weight of the aluminum paste composition; (b) applying the aluminum paste on a back-side of a p-type silicon substrate; (c) applying a metal paste on a front-side of the p-type silicon substrate, the front-side being opposite to the back-side; (d) firing the p-type silicon substrate after the application of the aluminum paste at a peak temperature in the range of 600° C. to 950° C.; and (e) firing the p-type silicon substrate after the application of the metal paste at a peak temperature in the range of 600° C. to 950° C.