兰州大学机构库 >物理科学与技术学院
两种典型稀土掺杂荧光粉中量子剪裁现象的研究
Alternative TitleThe study of quantum cutting in two kinds of typical phosphors doped with different rare earth ions
谢乐春
Thesis Advisor王育华
2009-05-27
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword量子剪裁 能量传递 量子效率 荧光粉
Abstract本论文以YPO4和LaBaB9O16为研究对象,研究了这两种基质中不同离子对之间的能量传递和量子剪裁现象。 首先利用水热法制备了YPO4: Ln (Ln = Gd3+, Tb3+, Tm3+, Yb3+), 通过对其紫外及真空紫外发光性质的研究,考察了“Tb3+—Gd3+”离子对和“Tm3+—Yb3+”离子对中的能量传递和量子剪裁现象,结果表明: (1) 通过对Y0.99-xYbxPO4:Tm3+0.01的发射光谱,激发光谱和Tm3+的1G4能级的衰减时间曲线的测试和分析,发现在Tm3+→Yb3+之间存在有比较明显的能量传递和近红外的量子剪裁效应,其量子剪裁过程可以用1G4→2F5/2 + 2F5/2表示。另外通过拟合后的衰减时间曲线可以计算出Tm3+→Yb3+之间最大的量子剪裁效率( )为172.8%。 (2) 通过对Y0.99-xGdxPO4:Tb0.01系列样品在真空紫外下的发光性质进行分析,发现在真空紫外下样品有很好的发光性能,并且随着Gd3+的掺杂浓度的变大,Tb3+的发射在增强,说明在该系列样品中有Gd3+→Tb3+之间的能量传递。但是在该基质中没有发现Tb3+—Gd3+之间的量子剪裁现象,其主要原因与磷酸盐中声子能量有关。 另外利用高温固相法制备了LaBaB9O16: Ln (Ln = Tb3+, Dy3+, Yb3+), 通过对其紫外发光性质和能级衰减时间的研究,考察了“Tb3+—Yb3+”离子对和“Dy3+—Yb3+”离子对中的量子剪裁现象, 结果显示: (1) 通过对La0.99-xYbxBaB9O16:Tb0.01的发射光谱,激发光谱和Tb3+的5D4能级的平均衰减寿命的分析和计算,发现在Tb3+→Yb3+之间存在有能量传递和近红外量子剪裁效应,其量子剪裁过程可以用5D4→2F5/2 + 2F5/2简单表示。另外利用FT-IR谱的分析发现,这种多硼酸盐中[B9O16]基团并不是单纯的由[BO4]和[BO3]基团组成,而是由[BO3]和[BO4]基团混合构成,主要以B-O键的振动和扰动为主。通过Tb3+的5D4能级的平均衰减寿命可以计算出Tb3+→Yb3+之间量子剪裁效率( ) 最大可以达到152.5%。 (2) 通过对La0.99-xYbxBaB9O16:Dy0.01的发射光谱,激发光谱和Dy3+的4F9/2能级的衰减寿命的分析和计算,发现在Dy3+→Yb3+之间也存在有能量传递。通过分析Dy3+和Yb3+的能级图,由于Dy3+的4F9/2能级能量恰好是Yb3+2F5/2能级能量的两倍,因此可以发生近红外量子剪裁效应,其量子剪裁效应可以用4F9/2 → 2F5/2 + 2F5/2表示。通过拟合后的曲线计算了在不同Yb3+掺杂浓度下的Dy3+的4F9/2能级的衰减寿命。发现随着Yb3+掺杂浓度的增大,衰减寿命从0.752 ms减小到0.61ms,这说明Dy3+→Yb3+之间存在有能量传递而加剧了Dy3+的4F9/2能级的衰减。最后计算了Dy3+→Yb3+之间量子剪裁效率( ),当Yb3+的掺杂浓度达到25%时, 达到最大值175.6%。 由于Yb3+离子发射出的近红外光子的能量(980—1000nm)刚好与硅基太阳能电池匹配很好,并且可以将一个可见光子转化为两个近红外光子,在理论上会使太阳能电池的效率大大提高,所以上述近红外量子剪裁荧光粉在提高太阳能电池效率方面有潜在的应用。
Other AbstractIn this paper, the phenomena of energy transfer (ET) and quantum cutting (QC) in YPO4 and LaBaB9O16 have been investigated, when doping different ions. First, the phosphors of YPO4: Ln (Ln = Gd3+, Tb3+, Tm3+, Yb3+) were synthesized by hydrothermal method. Then according to the study of photoluminescence (PL) properties under ultraviolet (UV) and vacuum- ultraviolet (VUV) excitation, ET and QC in Tb3+—Gd3+ and Tm3+—Yb3+ ions-couple were identified. The results have been presented as follow, (1) The experimental evidences of cooperative ET from Tm3+ to Yb3+ have been presented by the photoluminescence properties of YPO4:Yb3+, Tm3+ and the decay lifetime curves about the 1G4 emission of Tm3+. Near-infrared (NIR) QC involving the 2F5/2 → 2F7/2 emission of Yb3+ (about 970-1010 nm) is achieved upon the excitation of 1G4 energy level of Tm3+ at 474 nm. The NIR QC process could be expressed as 1G4 → 2F5/2 + 2F5/2. Quantum efficiency (QE, ) related to Yb3+ concentration is calculated, and the maximum efficiency reaches 172.8%. (2) The PL properties of Y0.99-xGdxPO4:Tb0.01 under VUV excitation has been investigated and the emission intensity of Tb3+ reached maximum when the concentration of Gd3+ was 10%. Besides, according to the analysis about PL properties, it was indicated that ET from Gd3+ to Tb3+ occurred with increasing the concentration of Gd3+. However, QC in Tb3+—Gd3+ couple had not been observed because of the energy of phonons in phosphate. In addition, the phosphors of LaBaB9O16: Ln (Ln = Tb3+, Dy3+, Yb3+) were prepared by conventional solid-state reaction under reducing atmospheres. Then ET and QC in Tb3+—Yb3+ and Dy3+—Yb3+ ions-couple were researched on via the investigation on UV PL properties and the decay lifetimes of energy levels. The conclusion have been shown as follow, (1) According as the PL properties of La0.99-xYbxBaB9O16:Tb0.01 and decay lifetimes, it was concluded that ET and NIR QC from Tb3+ to Yb3+ existed in polyborates and the QC process could be expressed as 5D4 → 2F5/2 + 2F5/2. NIR QE ( ) was calculated by mean decay lifetimes and the maximum QE of 152.5% was obtained. Besides, from the analysis of FT-IR spectrum, the structure of [B9O16] in this polyborates not only consists of [BO3] group but also [BO4] group. (2) The cooperative ET and QC from Dy3+ to Yb3+ had been investigated by the emission spectra of Dy3+, Yb3+, and the decay lifetimes of the 4F9/2 of Dy3+. When excited at 474 nm, two near-infrared photons had be...
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229610
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
谢乐春. 两种典型稀土掺杂荧光粉中量子剪裁现象的研究[D]. 兰州. 兰州大学,2009.
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