Selectively transparent and conducting photonic crystal solar spectrum splitters made of alternating sputtered indium-tin oxide and spin-coated silica nanoparticle layers for enhanced photovoltaics

Selectively-transparent and conducting photonic crystals (STCPCs) made of alternating layers of sputtered indium-tin oxide (ITO) and spin-coated silica (SiO2) nanoparticle films exhibit Bragg-reflectance peaks in the visible spectrum of 95% reflectivity and have a full width at half maximum that is greater than 200 nm. At the same time, their conductive properties are comparable to that of solid sputtered ITO films. Moreover, the average transmission of the STCPCs in the pass-band can be increased to ∼88%, or within 3.3% of the bare glass slide they are fabricated on. Furthermore, we also show that these STCPCs can readily be fabricated on textured surfaces similar to those used for micromorph solar cells. In this context wave optics analysis shows that these STCPCs can be utilized as intermediate reflectors that boost the relative photo-current generated in textured micromorph cells by more than 20% over a broad range of incident angles.

► Conductive and transparent Bragg-reflectors made with silica nanoparticle films.
► >95% Bragg-reflectance peaks with FWHM >200 nm in the visible spectrum.
► Average pass-band transmission as high as 88%.
► Can be fabricated on textured TCO substrates used in micromorph cells.
► Wave optics analysis shows a photocurrent increase of >20% in micromorph cells.