Thick film pastes for fire through applications in solar cells

摘要

Formulations and methods of making solar cell contacts and cells therewith are disclosed. The invention provides a photovoltaic cell comprising a front contact, a back contact, and a rear contact. The back contact comprises, prior to firing, a passivating layer onto which is applied a paste, comprising aluminum, a glass component, wherein the aluminum paste comprises, aluminum, another optional metal, a glass component, and a vehicle. The back contact comprises, prior to firing, a passivating layer onto which is applied an aluminum paste, wherein the aluminum paste comprises aluminum, a glass component, and a vehicle.

主权项

1. A method of making a photovoltaic cell comprising:
a. providing a silicon wafer having a first side and a second side, b. applying a phosphorus source to the first side of the silicon wafer, c. firing the wafer to form a phosphorus glass layer on the first side of the silicon wafer, d. removing at least a portion of the phosphorus glass layer from the first side of the silicon wafer, e. polishing the second side of the silicon wafer, f. applying a passivating layer to the first and second sides of the wafer, g. applying to the first side a silver paste comprising, prior to firing,
i. silver,ii. a glass component, andiii. a vehicle, h. applying to the second side an aluminum paste comprising, prior to firing,
i. aluminum,ii. a glass component, andiii. a vehicle, wherein (g) and (h) can be performed in any order, and i. firing the wafer for a time and temperature sufficient to adhere the silver to the front side and the aluminum to the back side, thereby forming front and back contacts.