• Yang, Y.
• Ho-Baillie, A.
• Pillai, S.
• Kampwerth, Henner
• Green, M. A.
• Mehrvarz, H.

Abstract

SeriesInformation ; 26th European Photovoltaic Solar Energy Conference and Exhibition; 2206-2209 ; Abstract ; In this paper, we found a way to apply scattering rear reflectors by means of Ag nanoparticles to the rear of front-planar high efficiency PERT (Passivated Emitter and Rear Totally-Diffused) solar cell. The optical absorption and spectrum response results have been compared for the planar and scattering rear reflectors. Conventional planar Al reflector only increases the spectrum response at 1150 nm by 1.4-fold, while the new fabricated scattering reflector by Ag nanoparticles enhance the spectrum response at the same wavelength by 4.0 fold. Moreover, by adding a detached metal mirror, the enhancement from the scattering rear reflector reaches to 5.3-fold. The photocurrent from 900 nm - 1200 nm was improved by 7.7% using planar Al reflector. 15.6% by Ag nanoparticle scattering reflector and 22.3% when combined with a detached metal film. We characterize solar cell light trapping features by calculating the normalized effective optical path length Z, obtaining a maximum Z value of 17.5 from the best performing scattering reflector at 1200 nm. The optical properties of rear scattering structures under different rear passivating SiO2 thicknesses were also investigated. We found that thin rear surface passivation layer brings higher absorption enhancement for near band-gap wavelength light, owing to the higher coupling efficiency and increased scattering cross-section from Ag nanoparticles deposited on thin spacer layer. Optical properties of scattering reflectors combined with Ag nanoparticles, oxide capping layer, and evaporated/detached metal layer were also studied in the paper.

Topics

• nanoparticle
• surface
• Silicon