No abstract

Significant photocurrent enhancement has been achieved for evaporated solid-phase-crystallized polycrystalline silicon thin-film solar cells on glass, due to light trapping provided by Ag nanoparticles located on the rear silicon surface of the cells. This configuration takes advantage of the high scattering cross-section and coupling efficiency of rear-located particles formed directly on the optically dense silicon layer. We report short-circuit current enhancement of 29% due to Ag nanoparticles, increasing to 38% when combined with a detached back surface reflector. Compared to conventional light trapping schemes for these cells, this method achieves 1/3 higher short-circuit current.

Polycrystalline silicon films of 10 mm thickness are formed on glass in a single-step continuous wave diode laser crystallisation process, creating large crystal grains up to 1 mm wide and 10 mm long. Solar cells are formed on the layers by employing a rear point contacting scheme. Intermediate layers between the glass and the silicon are shown to heavily influence the cell characteristics. A stack of silicon oxide/silicon nitride/silicon oxide has produced the best cell efficiency so far of 8.4 % with open-circuit voltage of 557 mV. With simple optimisation of the contacting scheme, 10 % efficient cells are expected in the near future.

A systematic investigation of the nanoparticle-enhanced light trapping in thin-film silicon solar cells is reported. The nanoparticles are fabricated by annealing a thin Ag film on the cell surface. An optimisation roadmap for the plasmonenhanced light-trapping scheme for self-assembled Ag metal nanoparticles is presented, including a comparison of rearlocated and front-located nanoparticles, an optimisation of the precursor Ag film thickness, an investigation on different conditions of the nanoparticle dielectric environment and a combination of nanoparticles with other supplementary backsurface reflectors. Significant photocurrent enhancements have been achieved because of high scattering and coupling efficiency of the Ag nanoparticles into the silicon device. For the optimum light-trapping scheme, a short-circuit current enhancement of 27% due to Ag nanoparticles is achieved, increasing to 44% for a "nanoparticle/magnesium fluoride/ diffuse paint" back-surface reflector structure. This is 6% higher compared with our previously reported plasmonic shortcircuit current enhancement of 38%.

No abstract

No abstract

No abstract

A doubling of the photocurrent due to light trapping is demonstrated by the combination of silver nanoparticles with a highly reflective back scatterer fabricated by Snow Globe Coating on the rear of a 2 μm polycrystalline silicon thin film solar cell. The binder free high refractive index titania particles can overcome light losses due to transmission. Modelling indicates that adding plasmonic nanoparticles to the back scatterer widens the angular distribution of scattered light such that over 80% of long wavelength light is scattered outside the Si/air loss cone and trapped in the cell, compared to 30% for the titania alone.