长余辉发光材料的研究进展

长余辉发光材料因其具有特殊的储能发光性能,是一类绿色环保型材料.综述了主要体系长余辉发光材料的研究历程,总结了长余辉材料的制备方法和余辉效应,概括了长余辉发光研究上存在的问题,提出了今后研究和应用的发展方向.     

稀土掺杂无机长余辉发光材料研究概况

主要介绍了长余辉材料的发展历史及其最近的发展概况;以及长余辉发光材料的主要分类,包括硫化物基长余辉发光材料,铝酸盐基长余辉发光材料和硅酸盐基长余辉发光材料等;并对长余辉材料发光机理的模型进行了比较详尽的探讨;同时根据长余辉材料的发展现状探讨了其研究方向和发展前景.     

长余辉发光材料的研究进展

铝酸盐长余辉发光材料因为其优异的性能,是一类新型储能和环保材料.本文主要综述了90年代发展起来的铝酸盐体系长余辉发光材料的研究进展.总结了铝酸盐长余辉材料的发光特征和长余辉特性,指出了制备技术上的最新方法,概括了长余辉发光模型,并提出了今后研究和应用的发展方向.     

掺杂长余辉发光材料的研究概况

长余辉发光材料是一种光致发光材料,具有广阔的应用前景。按照基质材料的不同,长余辉发光材料从最初的硫化物基质,逐渐发展形成了几大体系。系统地介绍了长余辉发光材料的分类,给出了各类型发光材料的典型代表,并对掺杂长余辉发光材料的研究历史和现状进行了综述。对各类型掺杂长余辉材料进行了横向和纵向对比,指出了存在的问题和进一步的研究方向,最后对长余辉材料的应用现状进行了简单介绍。     

稀土长余辉发光材料的研究进展

介绍了长余辉材料的类型(主要为硫化物型、碱土铝酸盐型及其它基质型余辉发光材料)及发展历史,总结了其研究现状与发光机制,概括了常规制备方法,指出了长余辉发光材料存在的问题和今后研究与应用的方向.     

碱土铝酸盐长余辉发光材料发光性能影响因素的研究进展

铝酸盐长余辉发光材料是一类新型储能和环保材料,其储光-发光性能受很多因素影响.在介绍以铝酸盐为基质,稀土为激活剂或主激活剂的新型长余辉材料的发光机理模型的基础上,重点综述了粉末粒度、基质结构、原料纯度、助熔剂等多种因素对铝酸盐发光材料长余辉性能的影响,并指出杂质猝灭也是影响其余辉特性的重要因素.     

长余辉发光材料的研究进展

长余辉发光材料在太阳能转换和利用方面具有独特的优势,是一类重要的光-光转换和节能材料。综述了长余辉发光材料的光谱特性、余辉时间以及相应的发光机理,简单介绍了长余辉发光材料的一些常见制备方法,并对今后研究的重点和方向做了展望。     

硅酸盐长余辉发光材料的最新研究进展

系统地分析和概括了稀土离子激活硅酸盐体系长余辉发光材料的种类、特性、组成、结构、发光机理和制备技术。并根据长余辉发光材料研究现状，探讨了硅酸盐长余辉发光材料的研究方向与发展前景。     

SrAl2O4:Eu2+材料的发光性能研究

制备了发光性能良好的SrAl2O4:Eu^2 材料，对其激光光谱、发射光谱和长余辉曲线进行了测试与分析讨论，结果表明长余辉衰减符合函数L＝ct^a（a＝0.754）形式。讨论SrAl2O4:Eu^2 材料的长余辉机理，指出长余辉应来自陷阱对空穴的俘获与缓慢释放。发现了SrAl2O4:Eu^2 材料的力至发光性能并分析了其可能原因。     

铝酸盐长余辉光致发光材料的制备及其发光机理的研究

回顾了长余辉光致发光材料的研究历程,比较了各种长余辉光致发光材料的物理化学性能,对以铝酸盐为基体的长余辉光致发光材料的制备方法进行了综合描述,并对其发光机理进行了详细的分析。     

Triply Hiding Optical Information via Excitation-Dependent Allochroic Photoluminescence Based on Cellulose Derivates

Optical encryption technologies are widely used in information security, whereas the technology with one single optical secret key can be easily cracked. Here, a triple encryption is reported, which hides patterned information in excitation-dependent allochroic materials with long afterglow, enhancing the security level. The allochroic materials are based on a uniaxial co-assembly structure of cellulose nanocrystals (CNCs) and silica. The assembled CNCs present blue emission with quantum yield of 19.8% under 367 nm UV radiation. The blue emission is maintained in the inverse structure when CNCs are calcinated and converted to carbon dots (CDs). The inverse uniaxial-assembly structure improves the CD emission by 6.7 times. The assembly structure can even improve the phosphorescence of CDs, leading to excellent excitation-dependent allochroic properties. Specifically, the materials maintain a cyan long afterglow luminescence at 480 nm after removing 365 nm UV light, whose lifetime is 0.492 s. Changing the excitation wavelength to 254 nm, a UV emission at 343 nm can be obtained, alongside a blue long afterglow luminescence of 420 nm, whose lifetime is 1.574 s. Combining with blue afterglow materials, optical encryption labels are prepared, which hide different patterned information in three scenarios: natural light, UV light, and afterglow luminescence.     

多色长余辉材料的发光性质及动态防伪应用

发光防伪具有可视性强、设计简便的特点, 是众多防伪技术中常用的方法。传统防伪材料存在发光颜色单一、防伪图案和颜色静态的缺点, 易于模仿, 亟需开发可实现动态、可靠防伪性能的发光材料。本工作采用水热法制备了铬掺杂镓锗酸锌多色长余辉材料, 并对其余辉性能和动态防伪应用进行研究。实验结果表明: 通过改变镓锗比, 可以调节蓝绿光和红光区的发射强度, 实现发光颜色的可调。该系列样品在波长为254和365 nm的紫外光激发下分别呈现白色和红色, 发光颜色具有多模态发光特征。此外该系列样品具有多色的余辉发光, 不同颜色的衰减速率不同, 可以实现余辉颜色随时间发生动态变化的效果。据此设计成的防伪图案, 发光颜色在时间维度上具有动态变化特性, 可显著提高防伪安全性, 表明所制备的铬掺杂镓锗酸锌多色长余辉材料在动态防伪领域有重要的应用前景。     

长余辉蓄光玻璃的制备及其性能研究

利用传统陶瓷制备方法合成了SrAl2O4:Eu,Dy长余辉发光粉体,该磷光体主发射波长位于520nm,余辉时间长达8h以上。并以硼硅酸盐低熔点玻璃为底材,掺杂该发光粉体,在一定温度下烧成,结果制得长余辉蓄光玻璃。研究还表明,烧成温度对该玻璃的发光性能影响较大,随着温度的升高,发光强度及余辉时间明显下降。     

Sunlight-activated long-persistent luminescence in the near-infrared from Cr(3+)-doped zinc gallogermanates

Visible-light persistent phosphors are being widely used as self-sustained night-vision materials because of their sufficiently strong and long afterglow (>10 h) and their ability to be excited by sunlight as well as room light. In contrast, persistent phosphors for near-infrared (NIR) wavelengths are lacking. Here we report a series of Cr(3+)-doped zinc gallogermanate NIR persistent phosphors that exhibit strong emission at 650-1,000 nm, extending beyond the typical 690-750 nm, and with a super-long afterglow of more than 360 h. These new NIR persistent phosphors are all-weather materials that can be rapidly, effectively and repeatedly charged by natural sunlight in almost all kinds of outdoor environment. Seconds to minutes of sunlight activation can result in more than two weeks of persistent NIR light emission. This new series of NIR persistent materials have potential applications in night-vision surveillance, solar energy utilization and in vivo bio-imaging.     

废玻璃再生利用制备长余辉蓄光釉面砖及其性能的研究

利用传统陶瓷制备方法合成了SrAl2O4:Eu,Dy长余辉发光粉体,该磷光体主发射波长位于520nm,余辉时间长达20h以上,将发光粉掺入适量的低熔点玻璃料,经780℃烧成30min合成了性能较好的低温发光釉料,以废玻璃,粘土为主要原料添加其它少量助剂,经过成型,预烧,将低发光釉料涂覆在其上,在一定温度下烧成,制得长余辉蓄光釉面砖。     

沉淀-燃烧法合成SrAl2O4:Eu2+,Dy3+长余辉材料

通过沉淀-燃烧法合成了SrAl2 O4∶Eu2+,Dy3+长余辉材料,对合成样品进行了物相、形貌、发光特性研究,探讨了尿素用量对材料发光性能的影响.结果表明,当尿素用量为原料中金属硝酸盐总物质的量的6倍时,产物主晶相为单斜晶系的SrAl2O4;激发、发射光谱均为宽带谱,峰值分别位于368nm、518nm处;测得初始发光亮度为18700mcd/m2,在暗室中放置9天后,仍可观察到明显发光现象.     

SrAl2O4:Eu2+,Dy3+光致发光搪瓷涂层的制备

稀土Eu^2 激活的铝酸盐发光材料是近年来新发展起来的新型长余辉光致发光材料，由于其发光亮度和发光余辉比传统的硫化物高许多，且无毒，无放射性，因而引起广泛关注，采用高温固相反应法制备了SrAl2O4:Eu^2 ,Dy^3 发光材料，并利用SrAl2O4:Eu^2 ,Dy^3 发光材料，参考普通搪瓷的制备工艺，制得了性能稳定的光致发光搪瓷涂层，余辉时间长达12h以上，这种发光搪瓷涂层可用于制造广告牌，交通标牌和建筑物标识牌等，在许多领域有应用前景。     

Preparation and characterization of an Hf-doped zinc silicate long-lasting phosphorescent material

Hf⁴⁺-doped Zn₂SiO₄ phosphor emitting long-lasting cyan light was prepared by the conventional high temperature solid-state technique. The emission spectrum of the Hf⁴⁺-doped phosphor exhibits one broad band peaking at 471 nm in the visible region excited by 254 nm. The cyan-light afterglow can last about 40 min in darkness after being irradiated with 254 nm UV lamp for 10 min (250 mW/cm²). The afterglow decay curve can be fitted into a second-order exponential curve. The thermoluminescence (TL) curve shows two glow bands centered at about 386 K (0.61 eV) and 440 K (1.56 eV), respectively, with the lower trap energy level being responsible for the long-lasting afterglow emission. A possible mechanism of the long-lasting phosphorescence based on the experimental results is proposed.     

Luminescent properties of long lasting phosphor Ca2MgSi2O7:Eu

Long afterglow phosphors (Ca_1−xEu_x)₂MgSi₂O₇ (0.002 ≤ x ≤ 0.02) were prepared by solid-state reactions under a weak reductive atmosphere. X-ray diffraction pattern, photoluminescence spectra, decay curve, afterglow spectra and thermoluminescence curves were investigated. The phosphors showed two emission peaks when they were excited by 343 nm, due to two types of Eu²⁺ centers existing in the Ca₂MgSi₂O₇ lattice. However, only one emission peak can be found in their afterglow spectra. Energy transfer between Eu²⁺ ions in inequivalent sites was found. A possible mechanism was presented and discussed. The afterglow decay time of Ca_1.998MgSi₂O₇:Eu_0.002 was nearly 12.5 h which means it was a good long lasting phosphor.     

BaAl_2O_4:Eu~(2+),Dy~(3+)长余辉发光材料的燃烧合成及其发光特性

以金属硝酸盐和尿素为原料,采用燃烧法合成了发青绿光的BaAl2O4:Eu2+,Dy3+长余辉发光材料。采用XRD、SEM、荧光分光光度计等手段对其进行分析表征。研究结果表明:随着燃烧温度升高,燃烧反应加剧,副产物BaCO3的含量减少,BaAl2O4的结晶程度增加,晶粒尺寸增大。Ba-Al2O4:Eu2+,Dy3+的激发光谱和发射光谱峰值分别为310nm和500nm,均呈宽谱带特征,其发光是由Eu2+的4f65d1→4f7跃迁引起,长余辉特性主要基于Dy3+的电子陷阱作用。