分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Er3+/Yb3+ co-doped Li3Ba2Gd3(MoO4)8 phosphors were synthesized by conventional solid state reaction method, and their structure and spectral properties were investigated. The diffuse reflectance spectra showed that the 4I15/2 → 4I11/2 transition of Er3+ and the 2F7/2 → 2F5/2 transition of Yb3+ ions were highly overlapped. Under the excitation of 980 nm, three up-conversion (UC) luminescence bands around 530, 555 and 660 nm were observed, corresponding to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions of Er3+ ions, respectively. The effects of the concentration and pumping power on the UC intensities of Li3Ba2Gd3(MoO4)8:Er3+/Yb3+ phosphors were investigated, and the possible UC mechanism was proposed based on the results.
分类: 材料科学 >> 陶瓷学 提交时间: 2023-02-01
摘要: 研究了在真空烧结过程中,分别添加0.04 wt %、0.06 wt %、0.08 wt %、0.4 wt %、0.6 wt %至0.8 wt %的MgO和正硅酸四乙酯(C8H20O4Si、TEOS)作为辅助烧结剂,考察了它们对Ce3+掺杂透明Y3Al5O12 (Ce:YAG)陶瓷微观结构和发光性能的影响。采用X射线衍射、扫描电镜/能谱仪、光学光谱、光致发光光谱以及电致发光光谱进行了对比研究。掺量为0.8 wt %的MgO和TEOS均能获得优势石榴石相,而掺量为MgO的Ce:YAG陶瓷的平均晶粒尺寸(~ 5 ~ 10 m)较TEOS (~ 20 ~ 25 m)更细,分布更均匀。在Ce:YAG陶瓷中加入大量MgO会导致MgO偏析,而过量TEOS则会导致Al2O3偏析。在MgO助剂的作用下,Ce:YAG陶瓷在308 nm处出现了一个强吸收峰,这是由于Mg2+的电荷补偿效应导致了Ce4+的存在。添加0.6% wt % TEOS时,Ce:YAG陶瓷的最佳透过率可达80% @ 800 nm,发光效率最高可达106 lm/W。实验证明,与Mg2+相比,Si4+具有更好的光效优化效果。
分类: 材料科学 >> 电子、光学、磁材料 提交时间: 2019-04-30
摘要: 我们成功合成了CsKNaLi(Li3SiO4)4:Eu2+ (CKNLLSO:Eu2+)作为UCr4C4型结构氧基家族的新成员。该荧光粉的基质化合物的晶体结构和能带结构分别通过Rieveld精修方法和密度泛函理论分析和计算。由于高度压缩和刚性的阴离子骨架,取代Cs格位的Eu2+在InGaN基紫外LED的激发下,发出了明亮的绿色荧光,半峰宽为55 nm.当温度升高到190℃时,CKNLLSO:Eu2+的稳定性仍然较好。采用浓度优化的CKNLLSO:4%Eu2+制成的LED器件发出的绿光的色坐标为(0.2320, 0.6016),相关色温为7314K。分析结果表明,这种荧光粉是一种很有前景的白光LED绿色荧光粉。
分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: We obtained a single phase BLS:Eu2+, Ce3+, Mn2+ phosphor by solid-state reactions. Eu2+, Ce3+, and Mn2+ gives rise to the blue, green, and red emission, respectively. The Mn2+ red emission can be effectively enhanced via energy transfers from both Eu2+ and Ce3+. Thus a tunable full color emission from 410 to 750 nm was realized in this single phosphor. The Eu2+ ! Mn2+ energy transfer mechanism was investigated by the fluorescence decay curves. This single phosphor exhibits an efficient excitation band covering from 390 to 410 nm, which matches well with the emission light of the efficient NUV chips. The optimized BLS:Eu2+, Ce3+, Mn2+ phosphor shows a high quantum efficient of $62% and a good color stability. When this single phosphor was combined with a 395 nm NUV-chip, an ideal white LED with a high color render index (CRI) of 85 and a correlated color temperature (CCT) of 6300 K was obtained. This demonstrates the promising application of the BLS:Eu2+, Ce3+, Mn2+ single phosphor for the NUV-based white LEDs.