Efficiency Improvement of Bifacial PERC Mono-crystalline Silicon Cells with SiO_xN_y/SiN_x as the Antireflection Coating

With antireflection coating (ARC), the Fresnel reflection at the gas-solid interface can be reduced, which is one of the effective means to improve the performance conversion efficiency (PCE) of crystalline silicon solar cells. We proposed to use SiO _xN_y(1)/SiN_x(3) stacking layer as a front-side ARC to enhance the efficiency of incident photon in commercial bifacial PERC monocrystalline solar cells (182 mm×182 mm). Compared with the conventional SiN_x(4) ARC, the SiO_xN_y(1)/SiN_x(3) ARC is much stronger in suppressing the photon reflectivity over the range of 300–500 nm, especially in the shorter wavelength regime. The average PCE can be as high as 23.227% under standard test conditions (AM1.5, 1000 W·m⁻², 25 ℃), as compared with that of the conventional SiN _x(4) ARC based cells (23.128%). According to the QE spectrum integrated current loss analyzed with the SERIS-V1.5 software, the current loss of the SiO_xN_y(1)/SiN_x(3) ARC cells was reduced to 0.867 mA·cm⁻². Meanwhile, other parameters, such an open-circuit voltage and filling factor, can be also improved to a certain extent, while the rear-side PCE is not obviously affected. In addition, yield rate of the SiO_xN_y(1)/SiN_x(3) ARC cells that are checked with EL testing can match well with the conventional SiN _x(4) based cells, demonstrating the potential for large-scale production.