Plasmonic reflection grating back contacts for microcrystalline silicon solar cells

Abstract

We report on the fabrication and optical simulation of a plasmonic light-trapping concept for microcrystalline silicon solar cells, consisting of silver nanostructures arranged in square lattice at the ZnO:Al/Ag back contact of the solar cell. Those solar cells deposited on this plasmonic reflection grating back contact showed an enhanced spectral response in the wavelengths range from 500 nm to 1000 nm, when comparing to flat solar cells. For a particular period, even an enhancement of the short circuit current density in comparison to the conventional random texture light-trapping concept is obtained. Full three-dimensional electromagnetic simulations are used to explain the working principle of the plasmonic light-trapping concept.

Diffraction and absorption enhancement from textured back reflectors of thin film solar cells

“…3 Alas, it took more than a decade before suitable periodic structures for solar cell fabrication were demonstrated, 4,5 and still some time elapsed before acceptable device efficiencies were demonstrated for thin film silicon solar cells with periodic interface textures. [6][7][8][9][10][11][12][13] From a modelling point of view, periodic structures pose fewer difficulties than random ones; consequently, many reports on rigorous calculations appeared. [14][15][16][17][18][19] While increasing computing power made the modelling faster and more accurate over the years, the understanding of the actual mechanisms of light trapping is still limited.…”

New progress in the fabrication of n–i–p micromorph solar cells for opaque substrates

“…As they have lower absorption coefficient in the NIR than other materials used as absorber layer in solar cells, a-Si:H and mc-Si:H layers necessitate light trapping to enhance the light path in the absorber layers, improving the probability that NIR photons will be absorbed and converted into electron-hole pairs. The desired light trapping can be achieved either via plasmonic effects [8][9][10] or via light scattering with random [11][12][13] and periodic [14][15][16] structures. Owing to its deposition sequence, the n-i-p configuration opens the route for direct depositions on opaque substrates like commercial ceramic tiles [17], flexible stainless steel [18,19] and plastic foils [20][21][22].…”

Thin-film silicon triple-junction solar cell with 12.5% stable efficiency on innovative flat light-scattering substrate

“…In general, textured electrodes or substrates on which cells are deposited are used to improve the short-circuit current density (J sc ). [3][4][5][6][7][8][9][10][11][12][13][14][15] However, most of the time, a rough surface induces structural defects in the device grown on top of it, leading to reduced opencircuit voltage (V oc ) and fill factor (FF). 12,[14][15][16][17][18] Therefore, a compromise between roughness for efficient light scattering (high J sc ) and smoothness for high V oc and FF has to be made.…”