Diffusion Paste Development for Printable IBC and Bifacial Silicon Solar Cells

Increasing cell efficiency and lowering the cost of solar cell manufacturing is a continuous challenge in solar cell industries. Higher efficiency concepts like interdigitated back contact (IBC), and bifacial cells, with using thinner silicon solar cells are ways to reduce the total solar cell manufacturing cost. Typically the high efficiency concepts require costly extra processing steps. Developing the proper paste for printing application of high efficiency concepts could make these designs cost effective and easily manufactured. These pastes can be printable in a continuous manner using processes like screen printing or ink jet printing. This paper describes newly developed low cost phosphorous, boron, and diffusion barrier pastes. It shows the characterization of the newly developed phosphorous paste (99-038), boron paste (99-033), and diffusion barrier paste (99-001). These low cost pastes can easily be printed and make high efficiency concept cell designs a low cost reality. Characteristic features of sheet resistance, junction depth and minority carrier lifetime is discussed.