Figure 1
FWPVs.
(a). Schematic three-dimensional representation and working scheme of a typical FWPV, with scattering occurring at the bottom layer. Excluding the non-trapped light (ray 1), some of the trapped light was directly incident to the solar cell (ray 2) or guided to the solar cell through TIR (ray 3), while some escaped from the top surfaces (ray 4) or edges (ray 5); furthermore, some light was absorbed by the waveguide material (ray 6). (b). Normalized EQE spectra of a poly-Si solar cell and a 3 × 3 1-cell FWPV. An obvious decrease in efficiency occurred at the UV region (below ca. 360 nm), due to the strong UV absorption of TiO2 NPs. (c). Normalized real and imitation specular reflections. Obvious differences appear at low incident angles (10–40°). The ideal Lambertian surface exhibited uniform scattering intensity at low incident angles, whereas the specular intensity of the TiO2 NP/PDMS layer increased more rapidly to become larger than that in the ideal Lambertian system. The ABg parameters were fitted to match the normalized measured results at incident angles from 10° to 60°.
