Dispersion effect on optimized design of anti-reflection coatings for passivated silicon solar cells dispersion

Based on the refractive index dispersion effect, the weighted average reflectivity was used as evaluation function, and the best film thickness parameters of the anti-reflection coatings for the space silicon solar cell was obtained by the intelligent optimization algorithm. The optimization results were compared with that of the anti-reflection coatings designed without considering the dispersion. It displayed that after optimizing, the minimal weighted average reflectivity of the MgF2/TiO2 and SiO2/TiO2 anti-reflection coatings were reduced by 36.6% and 37.6% under considering the dispersion effect than that without considering dispersion effect. And then the MgF2/TiO2 and SiO2/TiO2 anti-reflection coatings were deposited on the silicon solar cells with a thickness of 15 nm SiO2 passivation layer and optimized again. Comparing without considering dispersion effect, the minimal weighted average reflectivity in the case of dispersion was reduced by 43.9% and 33.7% for the MgF2/TiO2 and SiO2/TiO2 coatings with passivation layer, respectively. The optimal design of the anti-reflection coatings were carried out for the space silicon solar cells with different thickness passivation layer. It was found that the minimum weighted average reflectivity of the anti-reflection coatings increased with the increase of the thickness of the passivation layer, meaning that the anti-reflection effect got weaker and weaker. Finally, the anti-reflection coatings were redesigned when the thickness of the passivation layer was also considered as an inversion parameter considering the refractive-index dispersion effect or not. The results show that the anti-reflection film is more optimization by considering the dispersion. For the MgF2/TiO2/SiO2(passivation layer) film system, the optimal film thickness parameters are d1(MgF2)=97.6 nm, d2(TiO2)=40.2 nm, d3(SiO2)=4.9 nm. For the SiO2/TiO2/SiO2(passivation layer) film system, the optimal film thickness parameters are d1(SiO2)=85.1 nm, d2(TiO2)=43.4 nm, d3(SiO2)=1.8 nm.