Investigation on silver nanoparticles-based plasmonic antireflection and its impact on electrical performance of mono c-Si solar cells

Silver nanoparticles (NP´s) were fabricated from silver ultrathin film deposited by e-beam evaporation using an optimized process, followed by rapid thermal annealing (RTP) done at 400⁰C for 1 minute on mono c-Si solar cells. The optical reflection and the electrical performance of the solar cells with and without silver nanoparticles were studied and analyzed. Incorporating Ag NP´s improves the antireflection in IR wavelength range (700 nm-1200 nm) which is reflected as 7-8 % improvement in external quantum efficiency (EQE) in this range with weighted total reflectance (TWR) of 7 %. However, the high backscattering from NP´s which results in high reflection in UV-Visible range, reduces the EQE in this wavelength range. The short circuit current density (extracted from EQE) is reduced from 35.5 mA/cm² to 31.4 mA/cm² though the Sun´s V_oc measurement suggests that there is relatively no impact on open circuit voltage and pseudo FF due to SiN_x + NP´s-based antireflection. This investigation suggests that the NP´s combined with SiN_x ARC is good for solar cell performance improvement in the IR range but not for broad wavelength range (300 nm-1200 nm) which is important for c-Si solar cells. Thus, the use of nanoparticles on the front surface of the solar cells cannot be utilized efficiently; however its back scattering property may be utilized using NP´s at the back surface of the mono c-Si-based solar cell.