Abstract: A Cd-free colloidal quantum dot which is a core particle that is coated with a shell made from a compound semiconductor and serves as a core for the shell, and emits visible fluorescence upon irradiation with excited light having a wavelength of a near ultraviolet region or a blue region. The colloidal quantum dot is represented by a chemical formula: A (B11-x, B2x) (wherein 0<x<1), has Zn as a Group-II element in the A site, Te as a Group-VI element in the B1 site, and Se or S as a Group-VI element in the B2 site, and has an average particle diameter of 1 nm or more and 10 nm or less.

Abstract: Disclosed is an ultraviolet fluorescent material having high light emission efficiency, wherein the peak wavelength of ultraviolet light to be emitted can be controlled by having a quantum dot structure wherein a fine crystal of zinc oxide having an average diameter of 1-10 nm serves as a core, and the surface of the zinc oxide fine crystal is covered with at least one of LiGaO2, LiAlO2, NaGaO2 and NaAlO2, which has a crystal structure similar to that of the zinc oxide and low lattice mismatch and hardly suffers from structural defects, or a solid solution thereof.

Abstract: Disclosed is an ultraviolet fluorescent material having high light emission efficiency, wherein the peak wavelength of ultraviolet light to be emitted can be controlled by having a quantum dot structure wherein a fine crystal of zinc oxide having an average diameter of 1-10 nm serves as a core, and the surface of the zinc oxide fine crystal is covered with at least one of LiGaO2, LiAlO2, NaGaO2 and NaAlO2, which has a crystal structure similar to that of the zinc oxide and low lattice mismatch and hardly suffers from structural defects, or a solid solution thereof.

Abstract: The present invention provides a lowly toxic phosphor and a production process thereof, and more particularly, the synthesis of nanoparticles having a chalcopyrite structure, a phosphor by compounding with a metal chalcogenite, and a production process thereof. The phosphor is a first compound composed of elements of groups I, III and VI having a chalcopyrite structure, or composite particles or composite compound containing the first compound, and the particle diameter of the first compound, or the composite particles or composite compound, is 0.5 to 20.0 nm. The phosphor is produced by mixing a first solution (Solution A), in which one or more of copper (I), copper (II), silver (I), indium (III), gallium (III) and aluminum (III) are respectively dissolved and mixed in a solution to which has been added a complexing agent, and a second solution (Solution C), in which a chalcogenite compound has been dissolved, followed by heat-treating under pre-determined synthesis conditions.

Abstract: The photocatalyst according to the present invention which exhibits a high catalytic function in the visible-light range comprises an oxide composite having a heterojunction comprising a p-type oxide semiconductor and an n-type oxide semiconductor which have photocatalytic properties with each other and at least one of which has photocatalytic properties even in the visible-light range. The p-type oxide semiconductor having photocatalytic properties even in the visible-light range is exemplified by a perovskite-type oxide Ca(Zr0.95Y0.05)O3−&dgr;, and the n-type oxide semiconductor by an anatase-type titanium oxide.

Abstract: The photocatalyst according to the present invention which exhibits a high catalytic function in the visible-light range comprises an oxide composite having a junction formed by oxide semiconductors (I) and (II) which have photocatalytic properties with each other and whose energy levels of electrons at the bottom of the conduction band and energy levels of electrons at the top of the valence band in an energy band structure, based on the vacuum levels, differ from each other; at least one of the oxide semiconductors having photocatalytic properties even in the visible-light range. The oxide semiconductor (I) having photocatalytic properties even in the visible-light range is exemplified by a pyrochlore-related structural oxide Ce2Zr2O8.0, and the oxide semiconductor (II) by an anatase-type titanium oxide.

Abstract: This invention is concerned with ceramic substrates for multilayer interconnection. This invention is also concerned with a raw batch for ceramic substrates which require a calcining temperature as low as 1,000.degree. C. or lower upon their production, are low in dielectric constant and have a coefficient of thermal expansion close to that of silicon and also with a process for the production of the substrates. This invention makes use of a raw batch which permits the use of a low resistance conductor such as Ag-Pd, Ag, Au or Cu and also the production of substrates by low-temperature calcination. The raw batch contains borosilicate silicate glass powder, and aluminum borate powder and at a weight ratio of 40-80 percent to 20-60 percent. The raw batch can additionally contain one or more specific oxides in particular proportions.