Performance improved by point-contact electrodes and SiO2/SiNX layers at rear

The rear point-contact fabricated through the laser-opening technique for mass production was applied on the photovoltaic cells. Laser opening, different layers for passivation (SiO₂) and protection (SiN_X) were employed to investigate their impact on the performances of solar cells. The SiN_X layer protects the SiO₂ layer from being burnt through by aluminium paste at the co-firing step. A conversion efficiency (η) of 16.91% with an open-circuit voltage of 628 mV was obtained for the optimal cell, a stack structure with SiO₂ and SiN_X layers, which also achieves a lower contact resistance of 6.66 mΩ·cm² and a higher light-beam-induced current of 80.77 mA/cm². The optimal cell also showed longer lifetime and 3-4% increased quantum efficiency in the visible wavelength range. Therefore, the developed process has simplicity and reliability, is fast and cost-effective and could be applied to industrial applications.