Chemical solution route to conformal phosphor coatings on nanostructures

An experiment was conducted to show that polymer-assisted deposition technique (PAD) can be used as a solution technique to produce high-quality Eu:YVO₄ on glass, c-cut sapphire, and photonic lattice substrates. The yttrium nitrate solution was prepared by mixing 1.3g yttrium nitrate hexahydrate with 1.0g ethylenediamine-tetraacetic acid and 1.0g polyethyleneimine. All metal-polymer solutions were filtered through a 0.45-micrometer filter, diluted to 200 mL with nanopure water, and purified by amicon filtration with a 3,000MW cut-off filter. The coating solutions were spin-coated onto c-cut Al₂O₃ or display glass substrates were heated on a hot plate at 540°C for 1 minute. The film composition was determined by peak integration method, using the computer code RUMP. PAD produced a conformal coating of phosphor on the nanostructured anodisc® and silica inverse opals yielding highly luminescent materials.