Enhancing Broadband Antireflection Performance of Silicon Solar Cells Using Grass-Like Alumina via Atomic Layer Deposition

Nano grass-like alumina structures were fabricated on the front surface of tunnel oxide passivated contact (TOPCon) silicon solar cells to improve broadband antireflection performance. Under the AM1.5G and AM0 spectra from 300 to 1180 nm wavelengths, the nano grass-like alumina structures reduces the weighted reflectance by 0.9%abs and 1.1%abs. The integrated short-circuit current density increases by 0.7 mA/cm² and 1 mA/cm², respectively. These photocurrent gains are primarily caused by reducing the front-side reflection losses at short wavelengths. Additional benefits arise from reduced front-side escape losses at medium and long wavelengths. No additional surface recombination is observed after nano grass-like alumina structures integration, supported by minority carrier lifetime and IV measurements. The nano grass-like alumina structures also exhibit excellent low optical reflection loss at high incident angles. Finally, post-encapsulation reflectance measurements confirmed that the nano grass-like alumina structures retained superior broadband antireflective properties.