Development of Rear Contact Technologies for Next Generation High-Efficiency Silicon Solar Cells
- Georgia Institute of Technology, Atlanta, GA (United States)
Project Objective: The objective of this program is to develop low-cost high-quality rear contacts and fabricate production-ready high-efficiency monocrystalline (~20%) and multicrystalline (17-18%) silicon solar cells. This efficiency enhancement on thin Si wafers will help achieve the Solar America Initiative goal of a levelized cost of electricity less than 10¢ per kWh by 2015. Background: The efficiency of current c-Si solar cells is strongly dependent on back surface passivation because recent advances in crystal growth and cell processing can produce bulk diffusion lengths greater than the wafer thickness. Improving the rear contact quality realizes three benefits simultaneously: gain in absolute efficiency, ability to use lower quality thin wafers, and better Si utilization. In this project, we will investigate and develop four novel back contact technologies that can lower the back surface recombination velocity (BSRV) and enhance the back surface reflectance (BSR). These rear contact technologies include (a) novel dielectric passivation of the rear surface (b) local contact window opening through a dielectric by screen printing or laser patterning (c) a novel boron diffusion process for p+ back surface field (B-BSF) and (d) a-Si passivation of the p-type rear Si surface in conjunction with screen printed front contacts. Our device modeling and analysis shows that these technologies can raise production-ready large area cell efficiencies in our laboratory from 17.5-18.0% to ~20.0% and expedite their commercialization. These rear contact technologies will allow the use of thin Si wafers (100-150 μm) without any wafer warpage or compromise in cell efficiency.
- Research Organization:
- Georgia Institute of Technology, Atlanta, GA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
- DOE Contract Number:
- FG36-08GO18075
- OSTI ID:
- 1222648
- Report Number(s):
- DOE-GIT-18075
- Country of Publication:
- United States
- Language:
- English
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