How to
Prepare the Brightest Luminescent Coatings?
- Publication date
- Publisher
Abstract
We address here the question of studying
the parameters affecting the brightness of luminescent nanoparticulate
coatings, among which are the absorption rate, the internal quantum
yield of the phosphor nanoparticles, and the extraction factor of
the emitted light in a solid angle perpendicular to the substrate.
Experimental investigations are achieved on spray-deposited YVO<sub>4</sub>:Eu particles, a system whose synthesis and properties are
well documented so that particles of different sizes and microstructure
can be considered. This allows a quantitative evaluation of the factors
affecting film brightness. Considering a film made from raw colloidal
particles, this work shows that its brightness is limited by a factor
of 5 due to altered quantum yield of nanoparticles, a factor of 1.75
by dielectric effects and a factor of 2.4 by light extraction issues.
This investigation, through providing quantitative evaluations of
these different parameters, opens the way toward a possible rational
design of inorganic luminescent coatings, with a possible improvement
of brightness that could reach a factor of 30 as compared to simple
films made directly from colloidal suspensions