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

Abstract

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 Voc measurement suggests that there is relatively no impact on open circuit voltage and pseudo FF due to SiNx + NP's-based antireflection. This investigation suggests that the NP's combined with SiNx 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.