In this work, a novel red-emitting oxyfluoride phosphor Na₂NbOF₅:Mn⁴⁺ with an ultra-intense zero-phonon line (ZPL) was successfully synthesized by hydrothermal method. The phase composition and luminescent properties of Na₂NbOF₅:Mn⁴⁺ were studied in detail. The photoluminescence excitation spectrum contains two intense excitation bands centered at 369 and 470 nm, which match well with commercial UV and blue light-emitting diode (LED) chips. When excited by 470 nm blue light, Na₂NbOF₅:Mn⁴⁺ exhibits red light emission dominated by ZPL. Notably, the color purity of the Na₂NbOF₅:Mn⁴⁺ red phosphor can reach 99.9%. Meanwhile, the Na₂NbOF₅:Mn⁴⁺ phosphor has a shorter fluorescence decay time than commercial K₂SiF₆:Mn⁴⁺, which is conducive to fast switching of images in display applications. Profiting from the intense ZPL, white light-emitting diode (WLED) with high color rendering index of Ra = 86.2 and low correlated color temperature of T_c = 3133 K is realized using yellow YAG:Ce³⁺ and red Na₂NbOF₅:Mn⁴⁺ phosphor. The WLED fabricated using CsPbBr₃ quantum dots (QDs) and red Na₂NbOF₅:Mn⁴⁺ phosphor shows a wide color gamut of 127.56% NTSC (National Television Standard Committee). The results show that red-emitting Na₂NbOF₅:Mn⁴⁺ phosphor has potential application prospects in WLED lighting and display backlight.

Epoxy thermal conductive adhesives with high thermal conductivity and dynamic mechanical properties are important thermally conductive materials for fabricating highly integrated electronic devices. In this paper, micro-Al₂O₃ is used as a thermally conductive filler for the epoxy resin composite and investigated the effect of micron-sized alumina particle size on the thermal conductivity and dynamic mechanical property of epoxy resin by the transient planar hot plate method and DMA (Dynamic mechanical analysis). The experimental results show that with the same amount of alumina filling, the thermal conductivity and Tg (glass transition temperature) of epoxy/Al₂O₃ composite material decrease with the increase of alumina particle size. The maximum thermal conductivity of the composite material is 0.679 (W/mK), while the energy storage modulus of epoxy/Al₂O₃ composite material increases with the increase of alumina particle size, and the maximum energy storage modulus of the composite material is 160MPa. Compared with pure epoxy resin, the thermal conductivity and energy storage modulus have increased by 2.7 and 3.2 times, respectively. The epoxy/Al₂O₃ composite was applied to the COB (Chips On Board) type LED package, and the substrate temperature of the LED dropped to the lowest after 1.5 hours of operation using EP-A5 composite, and the temperature was stabilized at 38.2°C, indicating that the addition of 5-micron alumina composite has the best heat dissipation in the COB type LED package. These results are critical for the implementation of particulate-filled polymer composites in practical applications because relaxed material specifications and handling procedures can be incorporated in production environments to improve efficiency.

The CLP Publishing collects CLP journals and partnered optics and photonics journals, and provides readers an optical publishing platform with global influence. SPIE, OSA, CUP. Chinese Laser Press (CLP), established by Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS) and Chinese Optical Society (COS) in 2009, nowadays publishes eight journals and manages three online platforms.