Z.M. Yu,L.F. Shen,D.S. Li,E.Y.B. Pun,J. Guo,H. Lin
Tb(acac) 3 (TAH) and Eu(TTA) 3 Phen (ETP) doped polyacrylonitriles (PAN) have been electrospun into heterogeneous hybrid TAH/ETP/PAN and core-shell structured [(TAH/PAN) core + (ETP/PAN) shell ] wire-shaped flexible nanofibers with diameter of ∼350 nm. Differential photon releasing behaviors reveal the double-color-emitting potential of Tb 3+ /Eu 3+ combination systems and verify the effectiveness of coaxial configuration in avoiding the cross-relaxation between different rare earth ions. Luminous fluxes of the hybrid and the coaxial systems exceed 283.5 and 326.3 μlm under the excitation of 308 nm UVB-LED pump source, respectively. By adopting coaxial electrospun configuration, the color coordinates are tuned from (0.561, 0.332) in TAH/ETP/PAN to (0.435, 0.366) in [(TAH/PAN) core + (ETP/PAN) shell ] fibers, which demonstrates that the core-shell structure is promising to extend the dimension of color tuning. Nanofibrosis and electrospun configurations furnish a desired approach to develop multifunctional one-dimensional nanomaterials for color displays and optoelectronic sensors .
The key to developing laser-driven solid-state lighting lies in high-performance color converters, which must be thermally robust under the high-power density excitation of a laser. Phosphor-in-glass (PiG) films are considered as a kind of promising color converter for laser lighting, but the poor thermal dissipation of the glass matrix will cause large thermal quenching of the PiG films and hence low luminous flux of lighting sources. In this work, Al2O3 particles, acting as a heat transfer medium, are introduced into the La3Si6N11:Ce3+ (LSN:Ce3+) PiG film to form a composite color converter for realizing high-brightness laser lighting. By optimizing the ratio of glass frits to Al2O3 as well as the film thickness, the Al2O3–LSN:Ce3+ composite PiG film shows a luminance saturation threshold of 23.08 W mm−2, which is 26.3% higher than that of the Al2O3-free LSN:Ce3+ PiG film (18.27 W mm−2). The luminous flux of the composite PiG film under blue laser excitation is improved by 51.4% and reaches 3120 lm, and the luminous flux of the laser-driven white light can reach up to 2886 lm. It indicates that the Al2O3–LSN:Ce3+ composite PiG film would be an interesting color converter for producing high-brightness laser-driven white light.
Yufeng Huang,Yakai Feng,Xujun Sun,Ying Han,Dongshun Liu,Xiaohua Tan
Organic silicones have been used as encapsulant materials for light-emitting diodes (LEDs) for many years, while their performances need to be improved in order to satisfy the requirements of high-power LEDs. A ZrO 2 /silicone hybrid resin (ZHR) was synthesized for LEDs encapsulation by in situ sol-gel reactions. The oligosiloxane was synthesized as polymeric matrix by nonaqueous sol-gel condensation using diphenylsilanediol (DPSD), vinyltrimethoxysilane (VTMS), and 3-methacryloxy propyl trimethoxysilane (MPTMS) as monomers. Then zirconium propoxide was added into this polymeric matrix to be hydrolyzed to obtain the hybrid resin with a uniform dispersion of ZrO 2 nanoparticles. The Si–O–Zr covalent bond was detected and benefited for excellent dispersibility of the ZrO 2 nanoparticles and the well compatibility between organic and inorganic phases. The cured ZHR with 5 wt% ZrO 2 content showed high light transmittance (greater than 80% in visible light range), high refractive index (=1.56), and high thermal stability (no yellowing at 150°C for 240 hours). The luminous flux of the LED chip with ZHR encapsulant was 10% higher than that of the pure silicone resin, suggesting that ZHR has great application potential in the field of LED packaging.
危险品化学品经营许可证（带存储）