Toward High Solar Cell Efficiency with Low Material Usage: 15% Efficiency with 14 μm Polycrystalline Silicon on Glass

摘要

Liquid-phase-crystallized silicon (LPC-Si) is a bottom-up approach to creating solar cells with the potential to avoid material loss and energy usage in wafer slicing techniques. A desired thickness of silicon (5–40 μm) is crystallized with a line-shaped energy source, which is a laser, herein. The first part reports the efforts to optimize amorphous silicon contact layers for better surface passivation. The second part covers laser firing on the electron contact. It enables a controllable trade-off between charge collection and fill factor (FF) by creating a low resistance contact, while preserving a-Si:H (ⅰ) passivation in other areas. Short-circuit current density (JSC) is observed to be up to 33:1 mA cm~(-2), surpassing all previously reported values for this technology. Open-circuit voltage (V_(OC)) of up to 658 mV also exceeded every previous value published at a low bulk doping concentration (1 × 10~(16) cm~(-3)). Laser firing reduced JSC by 0:6 mA cm~(-2) on average but improved the FF by 22.5% absolute on average, without any significant effect on V_(OC). Collectively, these efforts have helped in achieving a new in-house record efficiency for LPC-Si of 15.1% and show a potential to reach 16% efficiency in the near future with optimization of series resistance.