Efficient Light Trapping Structures of Thin Film Silicon Solar Cells Based on Silver Nanoparticle Arrays

Abstract

We report on an investigation into the light trapping efficiency for structures of thin film silicon solar cells, with silver nanoparticle arrays at both front and rear surfaces of the cells. The light trapping efficiencies of the structures are quantified by the weighted mean values of the photons absorbed by the silicon layer, over a wavelength range of 400 to 1100 nm. The weighted mean values are calculated under various combinations of the structural parameters for the silver nanoparticle arrays. The results show that efficient light trapping structures of the solar cells can be achieved by carefully choosing the structural parameters of the metal arrays. This great light absorption by the cell is attributed to the effects induced by the surface plasmon excitation of the metal particles. Based on the analyses, we also suggest that the method employed in this work may be a useful tool to probe other similar structures of the solar cells with metal nanoparticle arrays.

Optimization of morphology of submonolayer metallic nanoparticles to enhance light trapping on a semiconductor surface

“…In practically meaningful problems of light-trapping in solar cells, the absorption profile is expected to be near constant value in the visible spectral range [5,12]. For example, in Ref.…”

“…In Ref. [12], optimal light trapping was achieved in the visible range by means of homogeneous plasmonic enhancement by a submonolayer of silver nanoparticles covering the silicon surface. Thereof, it seems quite reasonable to take as a target of optimization some constant value of local field enhancing, including the absorption in the system of nanoparticles.…”

“…where α 1 and α 2 are positive constants chosen from the theory of constrained optimization and the Karush- Taking the additional restriction of the surface coverage into account, the unconstrained problem (11) can be represented as the minimum of the effective target function (12). The second and the third terms in the righthand side of (12) with α 1 and α 2 are non-zero, when the surface density falls out of the restrictions .…”

“…The introduction of metallic nanoparticle arrays with different morphologies at the front and rear surfaces of the active layer of thin (few micrometers) silicon solar cells has been also shown to significantly modify the transmission of light at these contacts. Specifically, optimized morphologies to increase transmission at the front contact, while reducing it at the rear one, have been intensively discussed [12].…”

Absorption enhancement in thin film solar cells with bilayer silver nanoparticle arrays

“…However, the surface recombination rate increases with a rough surface and such solar cells have low material quality, resulting in degradation. A method for achieving light trapping in thin film solar cells is the use of metallic nanoparticles (NPs) [1][2][3][4][5][6][7][8][9][10][11][12][13]. Metallic NPs exhibit the phenomenon of surface plasmon resonance when illuminated with light of suitable frequency [14].…”