An inkjet composition for an inkjet printer, a light-emitting device including the same, and a method of manufacturing the light-emitting device are provided. The ink composition may include light-emitting diodes and a solvent. The solvent may have a first viscosity at a first temperature section that may be greater than a second viscosity at a second temperature section. The solvent may include an ester compound of citric acid, glycol, alkanediol, alkanolamine, alkenic acid, alkenol, a pyrrolidone group-containing compound, glycerol, a compound represented by Formula 1, a compound represented by Formula 2, or any combination thereof: ##STR00001##
Substituents in Formula 1 and Formula 2 may be understood as described in connection with the detailed description. Each of the light-emitting diodes may have a size in a range of about 0.1 μm to about 10 μm.

An inkjet composition for an inkjet printer, a light-emitting device including the same, and a method of manufacturing the light-emitting device are provided. The ink composition may include light-emitting diodes and a solvent. The solvent may have a first viscosity at a first temperature section that may be greater than a second viscosity at a second temperature section. The solvent may include an ester compound of citric acid, glycol, alkanediol, alkanolamine, alkenic acid, alkenol, a pyrrolidone group-containing compound, glycerol, a compound represented by Formula 1, a compound represented by Formula 2, or any combination thereof: ##STR00001##
Substituents in Formula 1 and Formula 2 may be understood as described in connection with the detailed description. Each of the light-emitting diodes may have a size in a range of about 0.1 μm to about 10 μm.

Disclosed is a composite particle for use in a marking that is suitable for identification/authentication purposes. The particle comprises at least one superparamagnetic portion and at least one thermoluminescent portion coated with an thermoisolating portion. Optionally also a thermoconductive portion between the superparamagnetic and thermoluminscent portions.

Disclosed is a composite particle for use in a marking that is suitable for identification/authentication purposes. The particle comprises at least one superparamagnetic portion and at least one thermoluminescent portion coated with an thermoisolating portion. Optionally also a thermoconductive portion between the superparamagnetic and thermoluminscent portions.

A thermochromic pigment composition comprising: (A) at least one electron-donor organic dye compound, (B) at least one electron-acceptor compound, and (C) at least one compound. The thermochromic pigment composition is microencapsulated and is useable in writing instruments.

A thermochromic pigment composition comprising: (A) at least one electron-donor organic dye compound, (B) at least one electron-acceptor compound, and (C) at least one compound. The thermochromic pigment composition is microencapsulated and is useable in writing instruments.

A method for obtaining at least one particle, including: (a) preparing solution A including at least one precursor of at least one of Si, B, P, Ge, As, Al, Fe, Ti, Zr, Ni, Zn, Ca, Na, Ba, K, Mg, Pb, Ag, V, Te, Mn, Ir, Sc, Nb, Sn, Ce, Be, Ta, S, Se, N, F, and Cl; (b) preparing aqueous solution B; (c) forming droplets of solution A; (d) forming droplets of solution B; (e) mixing droplets; (f) dispersing mixed droplets in a gas flow; (g) heating dispersed droplets to obtain the at least one particle; (h) cooling the at least one particle; and (i) separating and collecting the at least one particle. The aqueous solution is acidic, neutral, or basic. In step (a) and/or step (b) at least one colloidal suspension of a plurality of nanoparticles is mixed with the solution. Also, a device for implementing the method.

A method for obtaining at least one particle, including: (a) preparing solution A including at least one precursor of at least one of Si, B, P, Ge, As, Al, Fe, Ti, Zr, Ni, Zn, Ca, Na, Ba, K, Mg, Pb, Ag, V, Te, Mn, Ir, Sc, Nb, Sn, Ce, Be, Ta, S, Se, N, F, and Cl; (b) preparing aqueous solution B; (c) forming droplets of solution A; (d) forming droplets of solution B; (e) mixing droplets; (f) dispersing mixed droplets in a gas flow; (g) heating dispersed droplets to obtain the at least one particle; (h) cooling the at least one particle; and (i) separating and collecting the at least one particle. The aqueous solution is acidic, neutral, or basic. In step (a) and/or step (b) at least one colloidal suspension of a plurality of nanoparticles is mixed with the solution. Also, a device for implementing the method.

A photochromic composition having at least one photochromic naphthopyran-based component with R′ and R″ groups selected from hydrogen, alkyl, fluorinated alkyl, alkenyl, alkynyl, alkylaryl, cycloalkyl, alkoxy, halogen, amine, carbonate ester, carboxylate, aryl, substituted aryl, heteroaryl, substituted heteroaryl or a heterocyclic group and Ar′ and Ar″ groups selected from unsubstituted or substituted cyclic five-membered or six-membered structures including benzene, pyridine, thiophene, furan, carbazole, triphenylamine, dibenzothiophene, dibenzofuran, fluorine, naphthalene, anthracene and pyrene. The photochromic composition is excitable under a visible light range to produce a color change. A second photochromic naphthopyran-based component with a different thermal decay rate constant (k) may further be included in the photochromic composition. The photochromic composition is incorporated into color-changing inks and polymers.

A thermochromic pigment composition including: (A) at least one electron-donor organic dye compound, (B) at least one electron-acceptor compound, and (C) at least one compound corresponding to the following formula (I): in which: X is 0 or a single bond, Z is COO or OCO, R.sub.1 is O-alkyl or (CH.sub.2).sub.mCH.sub.3—R.sub.2 is OCO(CH.sub.2).sub.nCH.sub.3 or H, —y=0-3, —m=12-18; —p=8-18, and on the condition that, when X is 0, y is other than 0. The thermochromic pigment composition are also useable in thermochromic pigment microcapsules ink compositions including the thermochromic pigment microcapsules, and writing instruments including the ink compositions.