Dual-luminescence-center single-component white-light Sr2V2O7:Eu3+ phosphors for white LEDs

A high-performance white-light-emitting-diodes based on nano-single crystal divanadates quantum dots

“…The broad band emission for white light may consist of two parts. One part is the direct band gap transition from CB to VB, and that the transition probability of this part is often the most probable15252627. While the above experimental main peak value 2.259 eV (550 nm) is in good agreement with the theoretical direct band gap result 2.25 eV, evidently proving that this direct band gap transition should be the main origination of broad band emission.…”

“…1h). The η values of BVQD and SVQD measured at the wavelength of 325 nm at room temperature were respectively 95% and 93%, which are quite large among all the reported vanadate luminescent materials8151617. As shown in Fig.…”

“…2g. There are four characteristic peaks which correspond to the stretch vibrations of VO 4 dimers1516171819, namely, v 1  = 581 cm –1 , v 2  = 748 cm –1 , v 3  = 813 cm –1 and v 4  = 897 cm –1 .…”

“…Additionally, in Figs. 4c,4d, there are some electron transfer channels in left V-O bond not right V-O bond with an ELF value of 0.25, indicating that the luminescent is induced by one-electron charge-transfer transition from the oxygen 2 p orbital to the vacant 3 d orbital of V 5+ in the tetrahedral VO 4 with T d symmetry15. Subsequently, getting an additional electron, the tetrahedral VO 4 transforms the approximate C 3V symmetry, and in the meanwhile V 5+ for 3 d 0 also changes into V 4+ for 3 d 1 .…”

Theoretical spectra identification and fluorescent properties of reddish orange Sm-doped BaTiO 3 phosphors

“…Rare-earth (RE) elements doped phosphors, due to the inherent chemical and physical stability ascribed to a partially filled inner (4f n ) shell shielded from its surroundings by completely filled outer (5s 2 and 5p 6 ) orbitals, reach overwhelming superiority over other phosphors in the fields of optoelectronic and photonic applications, ranging from solid-state lasers, displays to optical fiber telecommunication and phosphors for colors lamps [1][2][3][4][5][6][7][8][9]. Among them, trivalent samarium Sm 3+ with 4f 5 configuration has the excellently stable emission spectra in the range of visible light originated from the various possible transitions among 6 H , 6 P , 4 G, 4 F, 4 I, and 4 M, suggesting that Sm 3+ -doped phosphors for the application of light emitting diodes (LEDs), especially for white LEDs [10,11,4].…”