毕业论文-荧光材料的发光性能研究论文.doc

摘 要 在全球能源短缺的大背景下，半导体发光二极管（LED）作为一种新型光源，在照明市场上的前景备受全球瞩目。与第一代（白炽灯）和第二代（荧光灯）照明光源相比，它具有发光效率高、使用寿命长、无污染、可使用低电压和低电流、可小型化和轻薄化、节能等一系列优点。随着世界能源短缺和环保的要求，以21世纪的绿色照明光源半导体白光LED取代能耗高的白炽灯和易污染环境的汞激发荧光灯，已成为必然的趋势。采用传统的高温固相法制备了一系列单相蓝绿色Ca2Al2SiO7:Eu2 +荧光粉，并详细研究了其成相（XRD）和发光特性（PL）。Ca2Al2SiO7:Eu2 +的荧光粉的发射光谱包括蓝色波段（419nm）和绿色波段（542nm），而且随着Eu2 +的掺杂浓度和激发波长的改变，相对强度也随着改变，其发光性能归属于不同能级的Eu2+的4 f 7–4 f 65跃迁。本实验中还发现可通过改变基质的组分即改变基质晶体场强度，影响Eu2+的f-d的跃迁行为。本结果表明：Eu2+离子掺杂Ca2Al2SiO7荧光材料可作为潜在的近紫外激发LED用蓝绿光发光材料。 关键词：Ca2Al2SiO7；荧光材料；发光性能； ABSTRACT In the background of the global energy shortage, the semiconductor light emitting diodes LED as a new type of light source, have received particularly attention. As the most challenging application to replace traditional incandescent and fluorescent lamps, white light emitting diodes can offer benefits in terms of stability, energy saving, high luminous efficiency, longer lifetime, and environmental friendly, they are called the next-generation solid state light. A series of single-phase blue green emitting phosphors of Ca2Al2SiO7:Eu2+ has been synthesized by the solid-state reaction and investigated in detail by the X-ray powder diffraction XRD , photoluminescence PL properties in this study. The emission spectra of the Ca2Al2SiO7:Eu2+ phosphors consisted of a blue band 419nm and a green band 542nm , the relative intensities of which changed with the Eu2+ dopant concentration and the excitation wavelength. The 4f7–4f65d0 transition of Eu2+ ions at different energy level was attributed to the unique photoluminescence phenomenon for the Ca2Al2SiO7 host crystal structure. For the crystal field strength was considered to be tailed by controlling the host composition, the photoluminescence properties of Eu2+ ions was investigated by changing the host composition and some relative conditions. It was found that Eu2+ doped Ca2Al2SiO7 luminescent material can be used as potential near ultraviolet excitation LED as blue-green light emitting phosphors. Keyword: Ca2Al2SiO