A wavelength converting structure is disclosed, the wavelength converting structure including an SWIR phosphor material having emission wavelengths in the range of 1000 to 1700 nm, the SWIR phosphor material including at least one of a perovskite type phosphor doped with Ni.sup.2+, a perovskite type phosphor doped with Ni.sup.2+ and Cr.sup.3+, and a garnet type phosphor doped with Ni.sup.2+ and Cr.sup.3+.

Provided are a quantum dot material, a preparation method and use thereof. The quantum material includes a quantum dot, and a first cladding layer and a second cladding clad outside of the quantum dot, wherein the first cladding layer is located between the quantum dot and the second cladding layer. The quantum dot material provided herein has good water and oxygen barrier properties and good stability.

A core-shell type quantum dot comprising, a semiconductor nanocrystal core including at least In and P, and having group III-V elements as constituent elements and a single or a plurality of semiconductor nanocrystal shells having group II-VI elements as constituent elements covering the semiconductor nanocrystal core, wherein a buffer layer comprising semiconductor nanocrystals having group II-V elements as constituent elements is included between the semiconductor nanocrystal core and the semiconductor nanocrystal shell. As a result, quantum dots using group II-V semiconductor nanocrystals as a core and having improved fluorescence emission efficiency are provided.

Provided is a method of producing semiconductor nanoparticles that exhibit a band-edge emission, and are superior in quantum yield. The method includes raising the temperature of a first mixture containing a silver (Ag) salt, a salt containing at least one of indium (In) and gallium (Ga), a solid compound that serves as a supply source of sulfur (S), and an organic solvent to a temperature in a range of from 125° C. to 175° C., and heat-treating, subsequent to the raising of the temperature, the first mixture at a temperature in a range of from 125° C. to 175° C. for three seconds or more to obtain a solution containing semiconductor nanoparticles, and decreasing the temperature of the solution containing semiconductor nanoparticles. The solid compound that serves as a supply source of S contains thiourea.

A quantum dot including a multi-component core including a first semiconductor nanocrystal including indium (In), zinc (Zn), and phosphorus (P) and a second semiconductor nanocrystal disposed on the first semiconductor nanocrystal, the second semiconductor nanocrystal including gallium (Ga) and phosphorus (P) wherein the quantum dot is cadmium-free and emits green light, a mole ratio (P:In) of phosphorus relative to indium is greater than or equal to about 0.6:1 and less than or equal to about 1.0, and a mole ratio (P:(In+Ga)) of phosphorus relative to indium and gallium is greater than or equal to about 0.5:1 and less than or equal to about 0.8:1, a quantum dot-polymer composite pattern including the same, and a display device.

A quantum dot including a core including a first semiconductor nanocrystal including a Group III-V compound; and a semiconductor nanocrystal shell disposed on the core, the semiconductor nanocrystal shell including zinc, tellurium, and selenium, wherein the quantum dot does not include cadmium, and the semiconductor nanocrystal shell has a mole ratio of tellurium to selenium of less than about 0.025:1, a composition including the quantum dot, a quantum dot-polymer composite, a patterned layer including the composite, and an electronic device including the patterned layer.

A security system, such as a banknote, comprises: i) a substrate, ii) a first ink, which is applied on at least a part of at least one surface of the substrate, wherein the first ink includes at least one IR luminescent dye and/or at least one IR luminescent pigment, and iii) a second non-luminescent ink, which is applied on at least a part of at least one surface of the substrate onto which the first ink is/are applied, wherein the second ink includes at least one non-luminescent IR absorbing pigment and/or a least one non-luminescent IR absorbing dye, wherein the first ink and the second ink at least partially overlap on the at least one surface of the substrate, wherein the second ink is applied in the overlapping area onto the first ink, and wherein the emission spectrum of the first ink and the absorption spectrum of the second ink at least partially overlap.

A security system, such as a banknote, comprises: i) a substrate, ii) a first ink, which is applied on at least a part of at least one surface of the substrate, wherein the first ink includes at least one IR luminescent dye and/or at least one IR luminescent pigment, and iii) a second non-luminescent ink, which is applied on at least a part of at least one surface of the substrate onto which the first ink is/are applied, wherein the second ink includes at least one non-luminescent IR absorbing pigment and/or a least one non-luminescent IR absorbing dye, wherein the first ink and the second ink at least partially overlap on the at least one surface of the substrate, wherein the second ink is applied in the overlapping area onto the first ink, and wherein the emission spectrum of the first ink and the absorption spectrum of the second ink at least partially overlap.

The objective of the invention is to provide a wavelength conversion film demonstrating a high optical density, a wavelength conversion film forming composition used suitably for forming the wavelength conversion film, and a production method for a cluster-containing quantum dot that may be applied suitably to the wavelength conversion film and the wavelength conversion film forming composition. In this invention, for a wavelength conversion film containing a quantum dot converting blue light into red light or green light, the light beam transmittance of the wavelength conversion film at 450 nm wavelength is set to 40% or lower, the light beam transmittance of the wavelength conversion film at 650 nm wavelength is set to 90% or higher if the hue of the light beam after the wavelength conversion is red, and the light beam transmittance of the wavelength conversion film at 550 nm wavelength is set to 90% or higher if the hue of the light beam after the wavelength conversion is green.

The present inventive concept relates to a hybrid wavelength converter including both a metal halide perovskite nanocrystal particles and non-perovskite-based quantum dots or non-perovskite-based phosphors converting a wavelength of light generated from an excitation light source to specific wavelengths, and a light-emitting device including the same. By including metal halide perovskite nanocrystal particles and non-perovskite quantum dots or non-perovskite phosphors in the dispersion medium, the hybrid wavelength converter according to the present inventive concept enables to make simultaneous wavelength conversion to red and green light, and to be optically stable and improved color purity and luminescence performance without changing the emission wavelength range even with a lower cadmium content than the conventional quantum dot wavelength converter.