An object is to provide a multifunctional multi-piezo material having both high piezoelectric properties and high mechanoluminescence properties. It is a multi functional multi-piezo material represented by the chemical formula Li.sub.(1−X)(1+a)Na.sub.XNbO.sub.3:M.sub.Y (where M is at least one type of metal ion selected from transition metal ions), wherein the value of X is in the range from 0.10 or more to 0.98 or less, the value of Y is in the range from 0.0001 or more to 0.2 or less; and α is in the range from 0 or more. Such a multifunctional multi-piezo material has both high piezoelectric properties and high mechanoluminescence properties.

The present invention relates to a red phosphor, a preparation method thereof and a light-emitting device prepared therefrom. A particle of the red phosphor consists of a phosphor inner core having a chemical formula of A.sub.x1Ge.sub.z1F.sub.6:y.sub.1Mn.sup.4+ and an outer shell having a chemical formula of B.sub.x2M.sub.z2F.sub.6:y.sub.2Mn.sup.4+, wherein 1.596≤x.sub.1≤2.2, 1.6≤x.sub.2≤2.2, 0.001≤y.sub.1≤0.2, 0≤y.sub.2≤0.2, 0.9≤z.sub.1≤1.1, and 0.9≤z.sub.2≤1.1; A and B are independently selected from alkali metal elements; and M is Si, or Si and Ge. The red phosphor provided by the present invention has high luminous efficiency and stability. Moreover, the phosphor alone or in combination with other luminescent materials can be used for preparing a light-emitting device with high performance.

Disclosed is a quantum dot light emitting device including a ligand-substituted quantum dot light emitting layer with a polymer having amine groups. The introduction of the ligand-substituted quantum dot light emitting layer with a polymer having amine groups changes the energy level of an electron transport layer and enables control over the charge injection properties of the device so that the flow of electrons can be controlled. In addition, the ligand substitution is effective in removing oleic acid as a stabilizer of quantum dots to prevent an increase in driving voltage caused by the introduction of the additional material, achieving markedly improved efficiency of the device. Also disclosed is a method for fabricating the quantum dot light emitting device.

There is provided a display backlight (604), including an excitation source (644) for generating blue light (650); and a wavelength converter (654) being a unitary construction including a combination of a wavelength selective filter layer (658) bonded to a photoluminescence layer (660), where the photoluminescence layer (658) includes a green photoluminescence material and a red photoluminescence material; and where the wavelength selective filter layer (658) is transmissive to blue light and reflective to green and red light.

A display device including a light source (A), a color conversion layer (B), and a color filter (C), wherein the color conversion layer (B) contains quantum dots (B-r) that emit red light, the color filter (C) has a blue color filter (C-b), a green color filter (C-g), and a red color filter (C-r), and the display device satisfies α≤1.80 and (II) β≥63.0.

A phosphor composition of an embodiment and a light emitting device package including the same includes: a green phosphor excited by blue light to emit green light; a first red phosphor of a nitride series which is excited by the blue light and emits first red light; and a second red phosphor of a fluorine series which is excited by the blue light and emits second red light, and is capable of emitting white light without deterioration of optical characteristics at a high temperature while improving luminous flux and color reproduction rate as compared with a light emitting device package including a conventional phosphor composition.

The present invention provides a method for producing a fluoride fluorescent material, the method comprising: contacting potassium ions with first complex ions comprising tetravalent manganese ions and second complex ions comprising at least one member selected from the group consisting of elements belonging to Groups 4 and 14 of the Periodic Table in a liquid medium comprising hydrogen fluoride to obtain a dispersion containing fluoride particles represented by the following formula (I):
K.sub.2[M.sub.1−bMn.sup.4+.sub.bF.sub.6]  (I) wherein M is the at least one member selected from the group consisting of elements belonging to Groups 4 and 14 of the Periodic Table, and b satisfies the relationship: 0<b<0.2; adding a reducing agent to the dispersion; and contacting the fluoride particles in the dispersion to which the reducing agent is added with at least one of additional second complex ions and additional potassium ions in the presence of hydrogen fluoride to obtain a fluoride fluorescent material.

A method of increasing the luminescence efficiency of titanium-doped oxide crystal, used as a laser material, is disclosed. This is accomplished by tempering the crystal at a temperature from 1750° C. to 50° C. below the melting point of the oxide crystal in a hydrogen protecting atmosphere with a constant partial pressure of the aluminium suboxide Al.sub.2O gas. By applying the method of the present invention, its luminescence efficiency of titanium-doped oxide crystal increases by 10 to 50 percent, and possibly by as much as 100 percent or more compared to previous technological treatments.

A coated phosphor comprises phosphor particles, wherein said phosphor particles comprise manganese-activated complex fluoride phosphors; and a coating on individual ones of said phosphor particles, said coating comprising a layer of carboxylic acid material encapsulating the individual phosphor particles.

The purpose of the present invention is to provide a luster coating composition which can form a pearl color coating when used on automobile bodies, characterized in that bluish interference is insignificant in a highlight of the coating film, a yellowish transparent color is weak in a shade of the coating film and the white color development of the white base coating film is visible in every direction. The present invention provides a luster coating composition comprising an interference luster pigment and a titanium dioxide pigment, wherein a volume average particle size D90 of the titanium dioxide pigment is within a range of 700 to 1200 nm, and a volume average particle size D50 of the titanium dioxide pigment is within a range of 250 to 900 nm, and a mass ratio of the interference luster pigment and the titanium dioxide pigment is within a range of 10/1 to 5/1 represented in the mass ratio “the interference luster pigment/the titanium dioxide pigment”. The present invention further provides a multi layered coating film obtained by a method for producing a multi layered coating film in which the luster coating composition is used, and a multi layered coating film formed thereby.