Jianyan Ding, Xufeng Zhou and Yuhua Wang
Lanzhou University, China
Posters & Accepted Abstracts: Res. Rev. J Mat. Sci
The rare earth Eu2+/Eu3+ ions have been widely used to act as activator for phosphors, especially red phosphors. Compared with oxide, Eu2+ activated nitride based phosphors commonly present broad excitation band and red emission light due to the larger crystal field splitting and higher nephelauxetic resulting from N3- ions. The compact host lattices produced by the edge or face shared (Al, Si) N4 tetrahedrons present excellent thermal stability and high bright red emission light. However, its broad emission band resulted from 4f-5d transitions of Eu2+ ions leads to low color purity. Different from Eu2+ ions, Eu3+ activated phosphors can emit a sharp red emission light due to its f-f transitions, but sharp excitation band limits their application. For solving this problem, the charge transfer band of Eu3+-N3- in α-M3B2N4 (M=Ca, Sr) and Li2SiN2 has been investigated in our work. Meanwhile, Eu2+ activated Ca5Si2Al2N8 has also been displayed for comparison. The results show that Eu2+ or Eu3+ activated phosphors have its own advantages and disadvantages, which also indicates their different application in WLEDs and FEWs. Recent Publications 1. Ding J, Li Y, Wu Q et al. (2015) Novel red and green emitting Li 2 SiN 2: Eu 3+/Tb 3+ phosphors with a broad charge transfer band. Journal of Materials Chemistry C 3(33):8542-8549. 2. Ding J, Wu Q, Li Y, et al. (2016) Eu2+-activated Ca5Si2Al2N8 – A novel nitridoalumosilicate red phosphor containing the special polyhedron of separated corner-shared [Al2N6] and [Si2N6]. Chemical Engineering Journal 302: 466-474. 3. Ding J, You H, Wang Y, et al. (2018) Site occupation and energy transfer of Ce3+-activated lithium nitridosilicate Li2SrSi2N4 with broad-yellow-light-emitting property and excellent thermal stability. Journal of Materials Chemistry C 6(13):3435- 3444. 4. Ding J, Wu Q, Li Y, et al. (2017) α-M3B2N4 (M= Ca, Sr): Eu3+: a nitride-based red phosphor with a sharp emission line and broad excitation band used for WLED. The Journal of Physical Chemistry C 121(18): 10102-10111. 5. Ding J, Wu Q, Li Y, et al. (2016) Self-Activated Yellow Light Emitting Phosphors of α, β-Ca3B2N4 with Long Afterglow Properties. Inorganic Chemistry 55(21):10990-10998.
Jianyan Ding has expertise in Physics and Materials Science. At present, his main research interest is focused on nitride based red phosphors used for white light emitting diodes (WLEDs). In order to realize the red phosphors, several nitride based phosphors activated by Eu3+/Eu2+ have been reported by him. The red phosphors with narrow emission band and broad excitation band have been realized. However, there are still some problems need to be resolved, such as: thermal stability, quantum efficiency and preparation condition. In the future work, Eu3+/Eu2+ activated nitride based red phosphors would be improved through investigating the relationship between luminescence properties and crystal or electron structure.