Rare-earth doped nanoparticles

Rare-earth doped nanoparticles consist of a host lattice in which different dopants are introduced during synthesis. These combinations give rise of different emission colors and are not dependant on the size of the crystal.

These particles have an inorganic core consistent of a non-fluorescent material which is getting doped with another substance during synthesis. This dopant introduces lattice defects in the crystal structure with electron excess which can be excited to fluorescence. Examples for these structures are barium sulfate or gadolinium vanadate phosphate as host lattice doped with rare-earth elements like europium or ytterbium. The fluorescence properties of these kind of nanoparticles is compared to semiconductor ones not dependant on the size of the crystal, moreover exclusively on the sort and amount of doping agent. Hence, these particles do not have to be that monodisperse. The fluorescence lifetime of these systems lies in the area of ms and is generally relatively high. Furthermore these particles are stable against treatment with heat and surface modifications because their emission features are only dependant on the defects. Since the stabilizing capping molecules can be changed on these particles as well dispersion in most media is suitable.

Typical examples for this kind of particle class are our CANdots Series X, rare-earth doped nanoparticles on the basis of phosphate, vanadate or sulfate. They are very stable against outer influences, have characteristic emission features and can be processed as colorless solutions when unexcited. Therefore these particles are highly suitable for the use as security labels or ink.

Series X fluorescent rare-earth doped nanoparticles with different emission colors (blue, yellow, green and red) are a cheap alternative to our CANdots Series A. The different emission colors come from a variation in doping agent and amounts. Excitation has to be with short-wavelength UV light around 250 nm. These particles can be processed to a totally colorless dispersion in polar media and are therefore eligible as additive to fluorescent inks.

Dr. Christoph Gimmler

Dr. Christoph Gimmler

Dr. Jan Niehaus

Dr. Jan Niehaus

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CANdot Series X