An organic electroluminescent device having an anode, a cathode, and a light emitting layer between the anode and the cathode, in which the light emitting layer contains a first organic compound, a second organic compound, and a third organic compound that satisfy the following expression (A), the second organic compound is a delayed fluorescent material, and the third organic compound is a light emitting material, is capable of enhancing the light emission efficiency. E.sub.S1(A), E.sub.S1(B) and E.sub.S1(C) represent a lowest, singlet excitation energy level of the first, second and third organic compound, respectively.
E.sub.S1(A)>E.sub.S1(B)>E.sub.S1(C)(A)

The purpose of the present invention is to provide a mechanoluminescent material which can be exhibit brighter luminescence compared to traditional SAO mechanoluminescent material even with respect to small strains and which has a relatively high mechanoluminescent capability even when left to stand for a long period of time after excitation. Provided is a strontium aluminate mechanoluminescent material containing Zr ions, characterized in that the Zr ions are contained in a reduced state, the content of the Zr ions is 10 mol % or less, and in a thermoluminescence measurement, one or more luminescence peaks are observed at a temperature of 100 C. or higher.

A light-emitting device is described that includes a plurality of partially drivable light sources, and a color conversion component configured to convert at least part of incident light from at least part of the light sources and emit outgoing light falling in a different wavelength region from the incident light, where the color conversion component includes a pyrromethene derivative.

A composition formed of a mixture of two compounds having similar thermal evaporation properties that are pre-mixed into an evaporation source that can be used to co-evaporate the two compounds into an emission layer in OLEDs via vacuum thermal evaporation process is disclosed. The first and second compounds can have an evaporation temperature T.sub.1 and T.sub.2, respectively, of 150 to 350 C., and the absolute value of T.sub.1-T.sub.2 can be less than 20 C. The first compound can have a concentration C.sub.1 in the mixture and a concentration C.sub.2 in a film formed by evaporating the mixture in a vacuum deposition tool at a constant pressure between 110.sup.6 Torr to 110.sup.9 Torr, at a 2 /sec deposition rate on a surface positioned at a predefined distance away from the mixture being evaporated, where the absolute value of (C.sub.1C.sub.2)/C.sub.1 is less than 5%.

A family of phosphorescent emitter compounds containing a carbene ligand L.sub.A selected from the group consisting of: ##STR00001##
is disclosed. These compounds enhance the performance of OLEDs when incorporated therein.

Provided are fluorescent microparticles and/or nanoparticles that have a polymeric matrix and at least one porphyrinic macrocycle associated therewith. The porphyrinic macrocycles associated with the presently disclosed fluorescent microparticles and/or nanoparticles are in some embodiments selected from the group consisting of porphyrins (including 17,18-didehydrophorbines), chlorins (including phorbines), bacteriochlorins (including bacteriophorbins), and isobacteriochlorins (including isobacteriochlorins containing a fused E ring). In some embodiments, the porphyrinic macrocycles have structures selected from Formulas I and H. Also provided are populations made up of a plurality of distinct fluorescent microparticles and/or nanoparticles, methods of making and using the same, sets of separately detectable fluorescent microparticles and/or nanoparticles and methods for preparing and using the same, porphyrinic macrocycle-containing dyads conjugated to particles and methods for using the same to calibrate multi-laser flow cytometers, align and/or calibrate confocai fluorescence microscopes, and/or differentially labeling cells and/or other biomolecules, and biomolecules such as antibodies, fragments, and derivatives thereof covalently conjugated to the presently disclosed fluorescent microparticles and/or nanoparticles and/or to the presently disclosed porphyrinic macrocycle-containing dyads.

A composition formed of a mixture of two compounds having similar thermal evaporation properties that are pre-mixed into an evaporation source that can be used to co-evaporate the two compounds into an emission layer in OLEDs via vacuum thermal evaporation process is disclosed. The first and second compounds can have an evaporation temperature T.sub.1 and T.sub.2, respectively, of 150 to 350 C., and the absolute value of T.sub.1T.sub.2 can be less than 20 C. The first compound can have a concentration C.sub.1 in the mixture and a concentration C.sub.2 in a film formed by evaporating the mixture in a vacuum deposition tool at a constant pressure between 110.sup.6 Torr to 110.sup.9 Torr, at a 2 /sec deposition rate on a surface positioned at a predefined distance away from the mixture being evaporated, where the absolute value of (C.sub.1C.sub.2)/C.sub.1 is less than 5%.

Provided are fluorescent microparticles and/or nanoparticles that have a polymeric matrix and at least one porphyrinic macrocycle associated therewith. The porphyrinic macrocycles associated with the presently disclosed fluorescent microparticles and/or nanoparticles are in some embodiments selected from the group consisting of porphyrins (including 17,18-didehydrophorbines), chlorins (including phorbines), bacteriochlorins (including bacteriophorbines), and isobacteriochlorins (including isobacteriochlorins containing a fused E ring). In some embodiments, the porphyrinic macrocycles have structures selected from Formulas I and H. Also provided are populations made up of a plurality of distinct fluorescent microparticles and/or nanoparticles, methods of making and using the same, sets of separately detectable fluorescent microparticles and/or nanoparticles and methods for preparing and using the same, porphyrinic macrocycle-containing dyads conjugated to particles and methods for using the same to calibrate multi-laser flow cytometers, align and/or calibrate confocal fluorescence microscopes, and/or differentially labeling cells and/or other biomolecules, and biomolecules such as antibodies, fragments, and derivatives thereof covalently conjugated to the presently disclosed fluorescent microparticles and/or nanoparticles and/or to the presently disclosed porphyrinic macrocycle-containing dyads.

An optical marking device including at least a first layer and a second layer disposed at least partially opposite each other, at least one of the first and second layers having an optically variable element being able to change colour between a first colour and a second colour, the first and second colours contrasting from a colour of the other layer in such a way that when the optically variable element displays the first colour, the first layer is visible and when the optically variable element displays the second colour, the second colour is visible, or when the optically variable element displays the first colour, the second layer is visible and when the optically variable element displays the second colour, the first layer is visible.

Light emitting nanoparticles have improved photostability, thermal stability and emission properties, and a process of preparing the nanoparticles.