Abstract: The disclosure relates to the technical field of preparation of circularly polarized luminescence materials, in particular to a central chirality induced helical chiral tetradentate cyclometalated platinum (II) complex, an electronic device and application thereof. The central chirality induced helical chiral tetradentate cyclometalated platinum (II) complex provided in the disclosure has a general structure as shown in formula (I) or (I?) in which (I) and (I?) are enantiomers to each other: Helical chiral metal complex molecules can autonomously induce a whole tetradentate ligand to coordinate with metal ions in a less sterically hindered manner by means of a central chiral fragment La in the tetradentate ligand, to form an optically pure helical chiral metal complex-based circularly polarized luminescence material, without need for chiral resolution. Moreover, the material has high chemical stability and thermal stability, and has important applications in circularly polarized luminescence elements.

Abstract: The present invention provides a high radiation rate platinum complex based on 1,8-substituted carbazole and an application thereof. The luminescent material of the present invention can efficiently control the excited state properties of material molecules by introducing substituents at 1-, 8-position of carbazole, which increases components of metal-to-ligand charge transfer state (MLCT), and improves the intersystem crossing rate of molecules; at the same time, the introduction of substituents at the 1-, 8-position of carbazole can increase the dihedral angle thereof with a pyridine ring, which can improve the rigidity of molecules, effectively reduce the energy consumed by the vibration and rotation of the carbazole ring in the molecules, and reduce non-radiative attenuation. The described factors can jointly increase the radiation rate of material molecules and shorten the lifetime of the excited state.

Abstract: Disclosed are a central chirality induced spiro chiral tetradentate cyclometalated platinum (II) and palladium (II) complex-based circularly polarized luminescence material and an application thereof. Spiro chiral metal complex molecules can be autonomously induced by a whole tetradentate ligand to coordinate with metal ions in a less sterically hindered manner by means of a central chiral fragment La in the tetradentate ligand, to form an optically pure spiro chiral metal complex-based circularly polarized luminescence material, without need for chiral resolution. Moreover, the material has high chemical stability and thermal stability, and has important applications in circularly polarized luminescence devices.

Abstract: A method for preparing a sintered metal matrix diamond saw blade used for cutting a QFN packaging device includes steps of: preparing metal matrix by employing metal powder and inorganic filler, wet-mixing and stirring the metal matrix, adding diamond grains to form a mixed material with evenly distributed diamond grains, performing the mixed material through cold pressing for pre-shaping, preparing a sintered metal matrix diamond saw blade blank through hot-pressing sintering, and finally machine-shaping the sintered metal matrix diamond saw blade blank to meet the dimensional requirements. The firm interface metallurgical bond is formed between the metal matrix and the diamond grains by the hot-pressing sintering process, which enhances holding force of the metal matrix on the diamond grains, in such a manner that abrasive grains are not easy to fall off untimely during cutting, thus prolonging service life of the sintered metal matrix diamond saw blade.

Abstract: A method for preparing a sintered metal matrix diamond saw blade used for cutting a QFN packaging device includes steps of: preparing metal matrix by employing metal powder and inorganic filler, wet-mixing and stirring the metal matrix, adding diamond grains to form a mixed material with evenly distributed diamond grains, performing the mixed material through cold pressing for pre-shaping, preparing a sintered metal matrix diamond saw blade blank through hot-pressing sintering, and finally machine-shaping the sintered metal matrix diamond saw blade blank to meet the dimensional requirements. The firm interface metallurgical bond is formed between the metal matrix and the diamond grains by the hot-pressing sintering process, which enhances holding force of the metal matrix on the diamond grains, in such a manner that abrasive grains are not easy to fall off untimely during cutting, thus prolonging service life of the sintered metal matrix diamond saw blade.