•The luminescence intensity of S7.6ZSPO:0.04Eu3+ can be increased with Li+ ions co-doping.•The intensity of 595 and 618 nm emission bands achieved 2.93 and 3.32 times increases.•The optimal sample presented 1.26 times greater intensity than commercial DS-200.An effective strategy based on the host composition design has been adopted to obtain novel high luminescent efficiency red phosphor Sr7.6Zn1-xSc(PO4)7:0.04Eu3+,xLi+. This research reveals that Li+ ions co-doping can offer charge compensation in host Sr8ZnSc(PO4)7 with 5% mol Eu3+ doped and produce oxygen vacancies as the sensitizer transferring energy to nearby Eu3+. Meanwhile, Li+ ions can assist raising grain sizes of Sr7.6Zn1-xSc(PO4)7:0.04Eu3+,xLi+ phosphors by lowering their melting temperature, further improve their luminescence properties. The luminescence intensity of 595 and 618 nm emission bands of the optimal phosphor Sr7.6Zn0.97Sc(PO4)7:0.04Eu3+,0.03Li+ achieved 2.932 and 3.316 times increase compared with the sample without Li+ ions incorporated, and it presented 1.26 times greater intensity than commercially red phosphor DS-200. Meanwhile, it also presented excellent thermal stability. Thus, the novel phosphors Sr7.6Zn1-xSc(PO4)7:0.04Eu3+,xLi+ show the potential application value on WLEDs.In contrast to the lithium-free S7.6ZSPO:0.4Eu3+, with 3 mol% Li+ ions’ incorporation the luminescence intensity of 595 and 618 nm emission bands were increased to 2.932 and 3.316 times under 395 nm excitation, and their integrated luminescence intensity can present 1.26 times greater than commercially red phosphor DS-200.

The strategy of co-doping Li+ was used with the aim of enhancing the emission intensities of Sr8ZnSc(PO4)7 under near ultraviolet excitation. The luminescence enhancement was related to the deep defects VO¨ which were produced by the introduction of Li+ ion. Furthermore, much deep VO¨ were produced with the incorporation amount of Li+ ion increasing. As the sensitizer, the produced deep VO¨ can effectively tunnelling transfer energy to the nearby activator Dy3+ resulting in the photoluminescence enhancement in SZSPO:1.5%Dy3+,5%Li+. In addition, its yellow/blue emitting ratio and photoluminescent quantum yields both were improved under longer wavelength excitation. Furthermore, the excellent thermal stability of optimal SZSPO:1.5%Dy3+,5%Li+ excelled over commercial phosphor DS-200 below 225 °C. The electroluminescence properties of fabricated ABPD-WLED reach the optimum with V=10 V and I=800 mA (λex=365 nm) or 700 mA (λex=388 nm), then the bright white luminescence can be obviously observed. These photoluminescence, electroluminescence and thermal properties testified the potential application of Sr8ZnSc(PO4)7:1.5%Dy3+,5%Li+ as a new-style warm-white emitting LEDs phosphor.The mechanism of the luminescence enhancement is consider as that a little amount introduction of Li+ ion can produce defects LiZn′ and oxygen vacancies VO¨, and with the incorporation amount of Li+ increasing, the more deep VO¨ are produced. As sensitizer, the productive deeper VO¨ can effectively tunneling transfer energy to nearby activator Dy3+ inducing its photoluminescence enhancement.Download high-res image (151KB)Download full-size image

A Lewis acid promoted cascade cycloaddition/ring-opening of 2-furylcarbinols with alkyl or aryl azides is described. The reaction features an initial formal [3 + 2] cycloaddition to form a trisubstitued triazole motif, followed by a ring opening of furan to generate the (E)-configuration of the enone. A wide range of highly functionalized triazoles is expediently and efficiently synthesized in a highly step-economical manner.