【作者】 潘文；

【导师】 宁桂玲；

【作者基本信息】 大连理工大学 ， 化学工艺， 2009， 博士

【摘要】 硅酸盐磷光体是一类重要的光致发光材料，具有优异的化学物理性能和抗紫外辐射性能，成为近年来国内外学者们研究的热点。但是大部分硅酸盐磷光体的发光效率和余辉时间有待改进，故离产业化还有一定的差距，有必要通过研究组成变化进一步提高其发光性能。此外，合成硅酸盐磷光体主要采用的是传统的固相混料高温煅烧法，存在能耗高和因混料带来性能不稳定等固有缺陷，而且合成产物的粒径和形貌有待进一步改善。同时，如何开发非金属离子激活的硅酸盐磷光体，对于拓宽硅酸盐基磷光体的应用范围也具有重要意义。本文通过吸收磷光体材料相关机理和制备技术的最新研究结果，致力于探索组成关系和合成方法，制备出性能优越且形貌可控的硅酸盐磷光体。论文中详细地研究了碱土金属硅酸盐磷光体各组分对其发光性能的影响，开发了不同的湿化学法制备高性能磷光体，探索了温度、催化剂、合成方法及产物形貌等因素与磷光体发光性能的关系，并采用热重-差热分析（TG-DTG）、X-射线衍射（XRD）、荧光光谱（PL）、傅立叶变换红外光谱（FT-IR）、扫描电镜（SEM）、透射电镜（TEM）等表征手段对产物的结构和性质进行了分析。具体研究内容和结果如下：1．在基质Sr₂MgSi₂O₇中，RE³⁺（RE=Ce,Nd,Gd）可有效地把能量传递给发光中心Eu²⁺。本论文通过系统地研究碱土含镁硅酸盐磷光体的组成关系，探讨了磷光体各组分对其发光性能的影响。结果表明，通过改变SrO与SiO₂的比率，基质组成的变化引起磷光体发射光谱位置和发射峰强度的变化；RE³⁺（RE=Ce，Nd,Gd）作为共掺杂的稀土离子对磷光体各个方面性能有着积极的影响，来自RE³⁺的能量传递是提高磷光体发光性能关键所在。这就为研究碱土硅酸盐磷光体在紫外可见激发下的发光机理、改善商用硅酸盐磷光体的发光性能打下了基础。2．为了克服传统制备方法带来的固有缺陷，本论文尝试纳米包覆法和共沉淀法合成了碱土金属硅酸盐超细磷光体，并研究了样品的发光性能。研究结果表明：两种方法合成的磷光体在发光强度和余辉性能方面都有明显的提高。采用纳米包覆法制备的前驱物具有核壳结构形貌，对这种特殊结构的形成过程作了推断，并通过多方面分析肯定了这种形貌前驱物对于合成Sr₃MgSi₂O₈：Eu²⁺，Dy³⁺磷光体在各个方面性能的促进作用；APTES共沉淀法制备的Sr₂MgSi₂O₇：Eu²⁺,Dy³⁺硅酸盐磷光体具有可直接应用的超细颗粒度，而作为制备前驱物的硅源，APTES其特殊的厌水亲油性决定了合成出磷光体的优越性能。3．进一步考察了形貌控制对于硅酸盐磷光体发光性能的影响，基于范德华力和氢键作用力的特点，本论文通过改进的溶胶凝胶法，制备了微米级球形磷光体。研究结果表明：微米级球形颗粒可以很有效改善磷光体的发光性能；通过改变制备前驱物中氨水的量可以在一定程度上控制球形颗粒的大小；而继续增加氨水的量，可以实现从Sr₂MgSi₂O₇到Sr₃MgSi₂O₈基质晶格的转变，从而引起了光谱和余辉性能各方面的变化。4．为了突破光谱位置方面的局限性，又兼顾硅酸盐磷光体基质的优点，针对硅铝酸盐磷光体材料的研究逐渐成为该领域的热点之一。本论文采用醇盐水解溶胶凝胶法分别制备了SrAl₂Si₂O₈：Eu²⁺，Dy³⁺磷光体与Sr₂Al₂SiO₇：Ce³⁺，Tb³⁺磷光体，对比高温固相法合成磷光体，发光性能有显著的提高。特别是Sr₂Al₂SiO₇：Ce³⁺，Tb³⁺白色磷光体，其颗粒形貌呈准球形，同时可以通过调节浓度观察到Tb³⁺和Ce³⁺之间的能量传递。5．为了进一步拓宽硅酸盐基磷光体的理论研究深度和应用范围，本论文研究了非金属离子激活的无定型二氧化硅发光球体。提出了一种在碱性条件下合成微米范围内可调控的单分散发光硅球新方法，不需要加入有机或者无机的荧光团：用水热法制备了具有核壳结构的空心发光硅球，这种核壳结构空心球体在紫外光照射下具有蓝色的发射光谱。更多还原

【Abstract】 Afterglow phosphor is a kind of photoluminescence material which can absorb the excitation energy and slowly release the visible light after shutting down the stimulate source. Because of its unique chemical and physical characteristics, afterglow phosphor has an unexpectedly large field of applications, such as safety exigence, transportation, building anddecorating...... Recently, silicate-based phosphor attracted much attention and became aninteresting topic in the field of afterglow luminescent materials because of their excellent chemical and physical properties and UV radiation resistance. However, compared with aluminate phosphor, silicate phosphor has relatively poor performance in luminescence efficiency and afterglow characteristic. It is necessary to study the relationship between the crystal structure and luminescence properties of silicate-based phosphor to further enhance its luminescent properties. Also, its synthetic route is the traditional solid-state reaction. The shortcomings of this approach are the need for high-temperature and long-time calcination. The unreacted phases appeared easily which reduced greatly its luminescent brightness and afterglow characteristic. Therefore, wet chemical approach to prepare silicate-based phosphor semms to be an attractive alternative. Especially in recent years, well-control over phosphor’s particle size and morphology to improve its luminescnt performance through the wet chemical approach became the goal of researchers’ studies. Meanwhile, because of its moderate synthetic conditions and controllable luminescence scope, non-metallic ions activated silicate-based phosphor has attracted people’s great interest. In the dissertation, with the recently development in synthetic technology and phosphor formation mechanism, we hope to overcome the above motioned question, develop effective silicate phosphor synthesis method, and improve the luminescent properties and morphology control of silicate phosphor. XRD, PL, FT-IR, TG-DTG, TEM, and SEM adsorption were used to characterize the silicate phsophor. The results are listed below:1. The relationship between the crystal structure and luminescence properties of silicate-based phosphor was systematic studied to further enhance its luminescent properties. The results showed that different ratio of SrO to SiO₂ in matrix lattice resulted in the variations of emission spectrum and intensity; Because of relatively lower concentration、trap density and depth of luminescence center Eu²⁺, luminescence intensity and afterglow performance is poorer in rich-Sr crystal phase; RE³⁺ （RE = Ce, Nd, Gd） as a co-doping rare earth ions has positive impact on the various aspects of phosphor performance and the persistent energy transfer from RE³⁺ to Eu²⁺ is the key to explain this phenomenon.2. Different wet chemical synthesis ways were applied to improve all aspects of alkine earth silicate phosphors’ performance. Long afterglow silicate phosphor which prepared by nano-coating method have better luminescence intensity and afterglow characteristic. Its precursor particles had core-shell structure and quasi-spherical morphology. This particular precursor’s structure has great influence on the phosphor’s performance in all aspects. Long afterglow silicate phosphor was also prepared by （aminopropyl）-triethoxysilane （APTES） co-precipitation method. Effects of synthetic temperature on the crystal characteristics, luminescent properties and afterglow performance of phosphors have been discussed in detail.3. By using modified sol-gel method, micron-size spherical Sr₂MgSi₂O₇:Eu²⁺, Dy³⁺ and Sr₃MgSi₂O₈:Eu²⁺, Dy³⁺ phosphor were obtained. With increasing the volume of ammonia in the preparation of the precursor, the phosphor’s particle size can be controlled to some extent. Further insceasing the ratio, it can be realized from Sr₂MgSi₂O₇ to Sr₃MgSi₂O₈ matrix lattice changes, which caused a series of changes in spectral properties and decay curves of as-synthesized phosphors.4. Rare earth activated silicate aluminate phosphor SrAl₂Si₂O₈:Eu²⁺,Dy³⁺ and Sr₂Al₂SiO₇: Ce³⁺,Tb³⁺ were prepared by the alkoxide sol-gel method. The resluts showed that phosphor prepared by alkoxide sol-gel method can provide more luminescent intensity and better afterglow characteristic compared with the same phosphor prepared by solid-state method. Especially for Sr₂Al₂SiO₇:Ce³⁺,Tb³⁺ white phosphor, the emission spectra of the samples with different doping concentrations showed that the Tb³⁺ emission was dominant because of the persistent energy transfer from Ce³⁺.5. Non-metallic ions activation amorphous silicon dioxide luminescent sphere were also studied in this thesis. A new class of monodisperse, luminescent silica spheres were produced upon calcination of hybrid amine-functionalized silica spheres. Silica microcapsules （hollow spheres） were synthesized successfully by combination of CTAB- stabilized water/oil emulsion system with mediated hydrothermal method. More importantly, it is also observed that under ultraviolet light excitation such a hollow core-shell structure spheres would emit blue light.更多还原