Exceeding 19% Efficient 6 Inch Screen Printed Crystalline Silicon Solar Cells with Selective Emitter

The process conditions for high efficiency industrial crystalline Si solar cells with selective emitter were optimized. In the screen printed solar cells, the sheet resistance must be 50-60 Omega/sq. because of metal contact resistance. But the low sheet resistance causes the increase of the recombination and blue response at the short wavelength. Therefore, the screen printed solar cells with homogeneous emitter have limitations of efficiency, and this means that the selective emitter must be used to improve cell efficiency. This work demonstrates the feasibility of a commercially available selective emitter process, based on screen printing and conventional diffusion process. Previous work, we announced about 18.5% efficient selective emitter solar cell by variation of heavy emitter pattern width. Now, we improved cell efficiency from 18.5% to 19% by transition of heavy emitter pattern and shallow emitter doping condition. A maximum cell efficiency of 19.05% is obtained on a 156 mm x 156 mm crystalline silicon solar cell. (C) 2011 Elsevier Ltd. All rights reserved.