Solar electricity: Realizing the dream through digital inkjet metallization of multi-crystalline Si solar cell

Solar electricity is an attractive resource that can be tapped without exhaustion. However, solar cell, the device which converts sunlight into electricity must be cost effective to encourage widespread use of solar electricity. Cost-effective solar cell can be achieved through material usage, efficiency and economy of scale. The economy of scale has been employed since 2004 with production capacities in the 1 GW range for several companies, but the efficiency is not high enough because of the limitations in the current metallization technology. The alternative technologies, such as laser opening and plate, extrusion, laser transfer process, inkjet and aerosol seed and plate investigated by several researchers are still far away from production ready. The inkjet metallization is an alternative that is very promising because of the associated precision in material usage in creating fine and uniform gridlines for reduced shading. Efficiencies of >19% and 17.4%, respectively, on mono and multi-crystalline cells, have been demonstrated using the same process as with the screen-printing technology. In this paper the results of digital inkjet metallization of multi-crystalline silicon solar cell is presented, for the first time, with efficiency of 17.4%. The technology road map to achieve lower-cost and higher efficiency multi-crystalline solar cells is also presented.