Improvement of self‐activated luminescence from introduced cation disorder in Sr₆V₂O₁₁

Abstract

Adjusting the elemental composition of a host is regarded to be an effective strategy to tune its luminescent properties such as peak energy, emission efficiency, and bandwidth. In this work, the cation substitution of (Ba2+ → Sr2+) in self‐activated Sr6V2O11 was conducted to investigate the luminescence modification. All the phosphors of Sr6‐6xBa6xV2O11 (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) were synthesized by the traditional chemical sol‐gel method. The morphological properties were measured through scanning electron microscope and energy dispersive spectrum measurements. The cation substitution brings out the disorder in the structure, which exerts modifications on the luminescence properties of Sr6V2O11. The luminescence intensity and corresponding decay lifetime were enhanced with the cation disorder in the self‐activated phosphor. Cation disorder in a phosphor lattice could be one of the effective approaches to improve the luminescence efficiency.

Unraveling the Photoluminescence Properties of the Sr10V6O25 Structure through Experimental and Theoretical Analyses

“…All samples show a broadband emission from 375 to 650 nm, with a maximum near 440 nm (2.82 eV) (see Figure b). These transitions are attributed to ligand–metal charge transfers in the tetrahedral [VO 4 ] cluster with T d symmetry. Given these results, a PL mechanism was proposed for the Sr 10 V 6 O 25 structure.…”

“…17 Strontium vanadate compounds are promising for use as lightemitting phosphors, and some structures have already been elucidated regarding the PL property, such as Sr 2 V 2 O 7 , 918 Sr 3 V 2 O 8 , 1920 and Sr 6 V 2 O 11 . 15 The optical properties of the Sr 10 V 6 O 25 structure have not yet been reported and are the subject of this paper. For this purpose, Sr 10 V 6 O 25 samples were synthesized using a microwave-assisted hydrothermal (MAH) system at 120 °C and with short synthesis times.…”

“…Strontium vanadate compounds are promising for use as light-emitting phosphors, and some structures have already been elucidated regarding the PL property, such as Sr 2 V 2 O 7 , Sr 3 V 2 O 8 , and Sr 6 V 2 O 11 . The optical properties of the Sr 10 V 6 O 25 structure have not yet been reported and are the subject of this paper.…”

“…The vanadate family has been considered promising for LEDs since they present a broadband emission covering almost the entire visible light region, high luminescence efficiencies, and excellent chemical stabilities. ,− In past years, different vanadate structures have been investigated, motivated by their luminescence properties. ,, Given that the vanadates exhibit the self-activated emitting properties of the VO 4 3– group, they can effectively convert UV radiation into visible light. , The luminescence mechanism of vanadium materials has been justified by the charge transfer in the VO 4 3– group from the 2p orbital of O 2– to the 3d orbital of V 5+ . The photoluminescence (PL) of the vanadium compounds is strongly dependent on the deformation degree of the VO 4 tetrahedron, which is influenced by the types and amounts of cations that are around the structure since the ( 3 T 1 , 3 T 2 → 1 A 1 ) forbidden transitions by the spin selection rule in the ideal T d symmetry become partially permitted by the spin–orbit interaction due to distortions in the VO 4 tetrahedron. Different photoluminescent emissions have been obtained by substituting the network-modifying cation and also by structural lattice changes …”

New Structural Design Strategy: Optical Center VO4-Activated Broadband Yellow Phosphate Phosphors for High-Color-Rendering WLEDs

“…These broad excitation bands are attributable to the CT absorption from the ground state 1 A 1 to the excited states 1 T 2 and 1 T 1 of VO 4 groups. 63,64 As the number of VO 4 centers increases, we observe that the excitation intensity of KBCP 2−x V x phosphors gradually increases, along with a spectral red shift from 341 to 356 nm. The red shift of the excitation spectra is attributable to the transition probability of 1 A 1 − 1 T 1 gradually increasing with increasing V 5+ content (Figure S2).…”