Analysis of Laser Injection Condition and Electrical Properties in Local BSF for Laser Fired Contact c-Si Solar Cell...

Area of Science:

• Materials Science and Engineering
• Photovoltaics and Renewable Energy

Background:

• Crystalline silicon (c-Si) solar cells are a dominant technology in photovoltaics.
• Local-back-contact (LBC) architectures offer potential for higher efficiencies by moving electrical contacts to the rear.
• Optimizing rear-side electrical properties, such as surface-recombination velocity (SRV) and contact resistance (Rc), is crucial for LBC cell performance.

Purpose of the Study:

• To investigate the impact of laser processing conditions on the electrical properties of LBC solar cells.
• To optimize laser parameters for achieving low contact resistance and effective local back surface fields (LBSFs).
• To correlate laser-induced changes with improvements in open-circuit voltage (VOC).

Main Methods:

• Fabrication of c-Si LBC solar cells incorporating optimized SRV, Rc, and LBSFs.
• Utilized a Nd:YAG laser (1064-nm wavelength) with varied power and frequency for laser firing.
• Characterized rear-side electrical properties, including LBSF thickness and contact resistance.

Main Results:

• Identified optimal laser conditions for creating effective LBSFs with reduced Rc.
• Achieved a contact resistance (Rc) of 0.125 ohms with an LBSF thickness of 2.09 μm at a laser frequency of 10 kHz and power of 44 mW.
• Observed a significant increase in open-circuit voltage (VOC) to 642 mV under optimized conditions.

Conclusions:

• Laser condition optimization is a critical factor for enhancing the performance of c-Si LBC solar cells.
• The study demonstrates a clear relationship between laser parameters, Rc, LBSF properties, and VOC.
• The findings provide a pathway for improving the efficiency and manufacturability of advanced silicon solar cell designs.