稀土掺杂LaGaO3荧光粉因具有优良的发光性能、 高的显色性和稳定性等优点而适合应用于场发射显示和LED器件中, 其中, LaGaO3∶Tb3+发光强度和色纯度高于商用Y2SiO5∶Ce3+荧光粉。 通过共掺Sn4+提高LaGaO3∶Tb3+荧光粉的发光性能使其更好地应用在白光LED中； 利用高温固相法制备一系列LaGaO3∶Tb3+和LaGaO3∶Tb3+,Sn4+绿色荧光粉, 并通过XRD和光致发光光谱分别对样品的晶体结构和发光性能进行表征。 结果表明： 掺杂Tb3+和Sn4+分别取代La3+和Ga3+进入到基质LaGaO3的晶体结构中, 并未出现其他杂相, 形成纯相的荧光粉。 样品的激发光谱均由位于231, 257和274 nm处的宽峰和位于300～500 nm锐利峰组成, 其中, 231和274 nm分别对应于Tb3+的4f-5d自旋允许跃迁（LS, 7F6→7DJ, ΔS=0）和自旋禁戒跃迁（7F6→9DJ, ΔS=1）； 257 nm归因于基质中GaO6基团自激活光学中心的跃迁； 300～500 nm锐利峰归因于Tb3+的f-f特征激发跃迁, 如7F6→5H6, 5H7, 5L6, 5L9, 5L10, 5G9和5D4。 相对于LaGaO3∶Tb3+, 共掺Sn4+主要提高Tb3+的4f-4f特征激发跃迁强度, 主激发峰由Tb3+的f-d跃迁变为f-f跃迁。 在380 nm光激发下, 样品LaGaO3∶Tb3+和LaGaO3∶Tb3+,Sn4+的发射光谱均由Tb3+的特征跃迁5D4→7F6 (487和493 nm), 5D4→7F5 (545 nm), 5D4→7F4(584和589 nm)和5D4→7F3 (622 nm)组成, 其中, 以5D4→7F5跃迁为主。 样品LaGaO3∶Tb3+和LaGaO3∶Tb3+,Sn4+的CIE色坐标分别位于绿色区域（0.287 4, 0.545 9）和（0.279 7, 0.576 1）； 荧光寿命分别为1.63和1.38 ms； 色纯度分别为54.81%和62.67%。 共掺Sn4+不仅没有影响发射峰的位置, 而且提高了发射强度（提高近一倍）, 改变样品的浓度猝灭机理, 由双极子-双极子(d-d)相互作用转变为双极子-四极子(d-q)相互作用。 LaGaO3∶Tb3+和LaGaO3∶Tb3+,Sn4+中Tb3+的最佳掺杂量分别为0.05和0.07； Sn4+的最佳掺杂量为0.03, 说明Sn4+共掺提高Tb3+的最佳掺杂量, 有利于发光强度的提高。 样品LaGaO3∶0.05Tb3+和LaGaO3∶0.07Tb3+,0.03Sn4+的光视效能（LER）分别为464和485 lm·W-1； 内量子效率分别为21.8%和39.2%。 随着温度的升高, 由于热猝灭, 样品LaGaO3∶Tb3+,Sn4+的发光强度逐渐下降； 但在140 ℃时, 发光强度仍可保持70%以上； 通过Arrhenian公式计算, 热活化能ΔE为0.169 0 eV, 说明样品具有良好的稳定性。 结果表明： LaGaO3∶Tb3+,Sn4+可作为绿色荧光粉实际应用于UV激发的白光LED器件中。

Rare earth doped LaGaO3 phosphors could be suitable for use in field emission display and LED applications, owing to the excellent luminescent properties, high color rendition and stability, et al. The luminescent intensity and color purity of LaGaO3∶Tb3+ are higher than those of commercial Y2SiO5∶Ce3+ phosphor. In order to expand application in white LED, the luminescent intensity of LaGaO3∶Tb3+ is enhanced by co-doping Sn4+ ions in this paper. A series of green phosphor LaGaO3∶Tb3+ and LaGaO3∶Tb3+,Sn4+ were synthesized by high-temperature solid-state method. The crystal structures and luminescent properties were characterized by XRD and photoluminescence spectrum, respectively. The results show that all Tb3+ and Sn4+ ions preferably substitute for La3+ and Ga3+ ions, respectively, in the crystal lattice of LaGaO3 without impurity phases, indicating obtained samples are single phase phosphors. All excitation spectra consist of some broad peaks (231, 257, and 274 nm) and sharp peaks (from 300 to 500 nm). The bands at 231 and 274 nm are assigned to the spin allowed transition (LS, 7F6→7DJ, ΔS=0) and the spin forbidden transition (7F6→9DJ, ΔS=1) for 4f-5d of Tb3+, respectively. The band at 257 nm is assigned to the transition of a self-activated optical center related to octahedral coordinated GaO6 groups. Some excitation peaks in the range of 300～500 nm are attributed to f-f characteristic transitions of Tb3+, such as 7F6→5H6, 5H7, 5L6, 5L9, 5L10, 5G9 and 5D4. Compared with LaGaO3∶Tb3+, co-doped Sn4+ ion can enhance the 4f-4f characteristic excitation intensity of Tb3+. The main excitation peak changes from f-d transition of Tb3+ to its f-f transition. Under excitation at 308 nm, the emission spectra of LaGaO3∶Tb3+ and LaGaO3∶Tb3+,Sn4 all consist of Tb3+ ions characteristic transitions, such as 5D4→7F6 (487, 493 nm), 5D4→7F5 (545 nm), 5D4→7F4 (584, 589 nm), and 5D4→7F3 (622 nm). The strongest emission peak is at 545 nm. The CIE color coordinates of LaGaO3∶Tb3+ and LaGaO3∶Tb3+,Sn4+ are (0.287 4, 0.545 9) and (0.279 7, 0.576 1) in green region, respectively. The fluorescence lifetime of LaGaO3∶Tb3+ and LaGaO3∶Tb3+,Sn4+ are 1.63 and 1.38 ms, respectively； the color purity values of LaGaO3∶Tb3+ and LaGaO3∶Tb3+,Sn4+ are 54.81% and 62.67%, respectively. Co-doped Sn4+ ion has no impact on the position of emission peaks, but the emission intensity of Tb3+ increases to nearly double. Mechanism of concentration quenching can be changed from dipole-quadrupole (d-q) to quadrupole-quadrupole (q-q) interactions. The optimum doping concentration of Tb3+ is 0.05 and 0.07 in the LaGaO3∶Tb3+and LaGaO3∶Tb3+,Sn4+, respectively. The optimum Sn4+ doping concentration is 0.03. The optimum doping concentration of Tb3+ increases by co-doped Sn4+, which is beneficial to improving luminous intensity. The luminous efficacy values of the radiation (LER) of LaGaO3∶0.05Tb3+ and LaGaO3∶0.07Tb3+, 0.03Sn4+ are 464 and 485 lm·W-1, respectively. The internal quantum efficiency values of LaGaO3∶0.05Tb3+ and LaGaO3∶0.07Tb3+, 0∶03Sn4+ are 21.8% and 39.2%, respectively. The emission intensity decreases gradually with the increasing temperature due to the thermal quenching. The emission intensity of the LaGaO3∶Tb3+,Sn4+ sample remains to be above 70% at 150 ℃. According to the Arrhenius equation, the thermal activation energy ΔE for quenching is calculated to be 0.169 0 eV, which indicates that this phosphor has excellent thermal stability. All the results show that the LaGaO3∶Tb3+,Sn4+ phosphor is a promising green phosphor for the n-UV excited w-LEDs.