• Yang, Yang
• Verlinden, Pierre J.
• Kho, Teng
• Chern, Kean
• Wong, Johnson
• Zhang, Xueling
• Huang, Qiang
• Mueller, Thomas
• Feng, Zhiqiang
• Aberle, Armin G.
• Zin, Ngwe
• Franklin, Evan
• Mcintosh, Keith R.

Abstract

<p>The collaboration between the Solar Energy Research Institute of Singapore (SERIS), Trina Solar and ANU is progressing well, and ANU has already developed all-back-contacted (ABC) silicon wafer cells with best one-sun efficiencies of 21.2% and 22.1% on FZ material, when measured with the aperture areas of 16 cm² (includes busbars) and 13 cm² (excludes busbars) respectively. This paper presents the continuing development of ABC cells targeting the efficiency of 23.5% on 16-cm² cell area. Further developments such as optimising front surface field (FSF), rear diffusion, anti-reflection coating (ARC), and incorporation of lithographically aligned metal contacts were undertaken on the ABC cells. Phosphorus diffusion of the FSF was made lighter from the sheet resistance of 190 Ω/□ to 240 Ω/□, resulting in the reduction of the saturation current density (J_oe) of the FSF by 22 fA/cm². The optimised thickness of anti-reflection coating (ARC) PECVD SiN_x further reduces the average reflectance across the wavelength range of 300 to 1200 nm by about 4%. Incorporation of aligned metal contacts and heavier rear phosphorus diffusion has contributed to the reduction in the total series resistance by 0.08 Ωcm². The above optimised improvements have increased the efficiency of the champion ABC cell by 0.5% absolute. In addition, we present further refinements in areas of texturing; FSF passivation; electrical shading loss in terms of cell pitch, busbar and base doping; and metallisation to aim for the 16-cm² ABC cells with the conversion efficiency &gt; 22% in the near term.</p>

Topics

• density
• impedance spectroscopy
• surface
• Silicon
• current density
• Phosphorus
• aligned