钙掺杂自激活锗酸锌长余辉材料的多色余辉及动态防伪应用

长余辉材料在安全指示、防伪和生物成像等领域具有广泛应用前景,但其缺陷调控及余辉机理尚不清晰。自激活长余辉材料以其物质组成及晶体结构简单,便于研究余辉机理而受到关注。本研究以自激活长余辉材料锗酸锌为基质,采用高温固相反应合成得到了一系列钙掺杂的长余辉材料Zn_2–xCa_xGeO₄(x=0、0.1、0.2、0.3、0.4、0.5)。实验表明,在锗酸锌中掺杂钙元素后,使用376nm紫外光激发时,观察到锗酸锌基质样品的黄色发光峰;同时在267 nm激发下, Zn_1.5Ca_0.5GeO₄荧光强度增强了6.2倍。从余辉光谱和余辉衰减曲线上看, Zn_1.5Ca_0.5GeO₄初始余辉强度增强了25.1倍;并且在所考察的300 s余辉时间里,与锗酸锌相比, Zn_1.5Ca_0.5GeO₄保持了近5倍的余辉强度。进一步热释曲线表征显示,材料主要陷阱的...     

天然多糖基室温磷光油墨的制备及防伪应用

目的 为解决常规发光防伪油墨环境不友好，防伪性能单一等问题，以生物基材料为刚性主体结构，芳香磺酸类化合物为客体分子制备水性生物基室温磷光油墨，探索其性能调控因素及包装防伪应用性能。方法 将生物基材料与芳香磺酸类化合物溶于水中获得室温磷光油墨，调控油墨组分、含量等因素，研究其对油墨黏度、油墨层磷光性能的作用机理，并套印不同发光颜色、余辉时长的防伪油墨，获得多色、动态发光的防伪图案，挖掘其包装防伪应用潜力。结果 实验表明，在水性油墨中，生物基材料添加的质量分数为8%，芳香磺酸类化合物添加量为0.16%时，油墨干燥后获得最佳的长余辉发光效果；使用模板刮涂方式印刷防伪图案，模板厚度为0.5mm时，防伪图案综合效果最佳。结论 具有丰富氨基、羟基等基团的生物基材料（如羧甲基壳聚糖、海藻酸钠），能形成具有强氢键作用的刚性结构，有效抑制芳香磺酸类化合物的非辐射跃迁，提升了所制备油墨的发光寿命和效率，有效提升了包装防伪油墨的环境友好度及防伪性能。     

小尺寸长余辉纳米颗粒的制备及发光性能

尺寸小且光学性能良好的长余辉纳米颗粒(PLNPs)在生物医学领域中具有广泛的应用前景。目前，PLNPs一般需要通过高温煅烧获得，而高温煅烧会造成颗粒团聚、尺寸过大、不利于在生物医学领域应用。因此，发展尺寸小且余辉发光性能良好的PLNPs制备方法具有重要意义。采用溶剂热法，以油酸和十八烯为溶剂，甲醇(CH₃OH)为辅助溶剂制备了铬掺杂镓酸锌PLNPs(ZGC-CH₃OH),对ZGC-CH₃OH煅烧后进一步用乙二胺四乙酸二钠进行刻蚀获得ZGC-CH₃OH-EDTA。研究了CH₃OH和EDTA刻蚀效应对PLNPs尺寸大小、余辉发光性能以及晶体结构的影响。结果表明：该方法制备的PLNPs(ZGC-CH₃OH-EDTA)不仅尺寸小，而且具有很长的余辉时间，其平均粒径为11.12nm,最大余辉发射波长为696nm, NIR余辉时间超过120h。     

硅铬共掺杂尖晶石长余辉材料Zn1+xGa2-2xSixO4:Cr3+中近红外余辉的增强及陷阱分布分析

本论文基于硅铬共掺杂, 合成得到了一种尖晶石长余辉材料Zn_1+xGa_2-2xSi_xO₄:Cr ³⁺。实验采用高温固相法, 按照设计的化学计量比精确称量ZnO、Ga₂O₃、SiO₂和Cr₂O₃等原料, 制备了一系列硅铬共掺杂的镓酸锌尖晶石长余辉材料, 其化学式为Zn_1+xGa_2-2xSi_xO₄:Cr ³⁺(x=0, 0.1, 0.15, 0.2, 0.5, 1)。实验结果表明: 采用硅铬共掺杂方式后, 引入合适浓度的硅离子可有效改善余辉性能。当x=0.2时, 样品余辉强度最佳, 相比ZnGa₂O₄:Cr ³⁺增强了3倍, 并且余辉持续时间长达24 h。进一步的陷阱分布分析表明, 在ZnGa₂O₄基质基础上引入硅掺杂, 可有效调控不同陷阱深度的分布。即在丰富的反位缺陷基础上, 硅的共掺杂可增加不等价替换缺陷和填隙缺陷等, 并可调控禁带宽度及缺陷形成, 从而实现改善余辉性能的目的。     

Gd2O2S发光材料的长余辉发光行为

使用固相合成技术制备了一系列Gd2O2S长余辉红色发光材料.在243nm紫外光激发下,具有很好的长余辉特性.这些发光材料具有多个发射峰,橙红色余辉发光是这些发射峰共同作用的结果.长余辉的形成是共激发离子Mg2+,Ti4+在Gd2O2S基质中形成一定浓度的电子陷阱的结果.在掺杂离子中,Ti4+的掺杂优于Mg2+的掺杂,而二者的共同掺杂获得了余辉特性更好的橙红色长余辉发光材料.     

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.     

绿色长余辉发光材料MgGa2O4:Mn2+的制备及性能研究

采用高温固相法合成了MgGa₂O₄:xMn²⁺(x=0.5%,1%,3%,5%)系列绿色长余辉发光材料。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、发光光谱、余辉光谱、热释光谱等表征手段对其长余辉发光性能进行了研究。样品的发射光谱的结果表明,Mn²⁺在509 nm处的特征发射峰,对应Mn²⁺离子的⁴T₁(⁴G)→⁶A₁(⁶S)电子跃迁,随着Mn²⁺掺杂浓度的增加,其发光强度先增强后减弱,掺杂浓度为3%时样品具有最好的发光性能;掺杂浓度为1%时其余辉强度最强,余辉时间可以持续1h以上;热释光谱在342 K附近出现一个宽峰,这表明样品存在大量的陷阱,这有利于捕获被激发的电子,形成长余辉发光。     

纳米级MgSiO3∶Mn2+,Nd3+红色发光材料的制备及发光性能

采用静电纺丝法制备MgO,SiO2,Nd2O3,MnCO3与PVA膜混合物,再通过高温固相法制备长余辉发光材料MgSiO3∶Mn2+,Nd3+,对这种红色长余辉材料的发光性能进行了研究。借助SEM对其表面形态进行表征,激发光谱、发射光谱和余辉衰减曲线表征样品的发光性能。研究发现,PVA及纺丝工艺没有对MgSiO3∶Mn2+,Nd3+样品的晶体结构造成破坏,样品发射峰型没有变化,相对可见光样品对紫外光的吸收更好。采用静电纺丝法制备的发光材料与高温固相法制备的发光材料相比其发光性能及粒径都有一定程度的改善。     

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。     

长余辉发光材料研究进展

第一次观察到Sm~(3 )、Tm~(3 )、Yb~(3 )的红色和橙红色长余辉发光;首次在含镉的氧化物中观察到红、绿、蓝等多种颜色的新型长余辉发光,特别第一次观察到非稀土离子如Pb~(2 )、Bi~(3 )、Sn~(2 )、Sb~(3 )的长余辉发光现象;首先发现在一种基质中由一种稀土离子(Dy~(3 ))激活产生的发白色光的长余辉发光材料;第一次观察到Er~(3 )、Ho~(3 )的绿色长余辉发光;在掺Tm~(3 )的材料中发现迄今为止未见国内外报道的800nm最长波长的长余辉发射;在掺Tm~(3 )的材料中初步观察到既有上转换发光又具有长余辉发射的新的发光现象;开展了长余辉发光材料的纳米组装,以及开拓这类材料在环境和生物医学领域的应用研究。研究的能产生长余辉发光的激活离子和基质化合物已有较大扩展,并发现了一些变化规律及用现有模型和规则难以说明和解释的新的现象。迄今,文献报道的具有长余辉发光的基质和离子主要是铝酸盐、硅酸盐、硫氧化钇等基质和Eu~(2 )、Eu~(3 )、Ce~(3 )、Tb~(3 )、Pr~(3 )、Mn~(2 )等离子,拓展到锗酸盐、钨酸盐、镓酸盐、石榴石、含镉的氧化物以及稀土硫氧化物等...     

Recent Advances of Carbon Dots with Afterglow Emission

Carbon dots (CDs) have gradually become a new generation of nano-luminescent materials, which have received extensive attention due to excellent optical properties, wide source of raw materials, low toxicity, and good biocompatibility. In recent years, there are many reports on the luminescent phenomenon of CDs, and great progress has been achieved. However,there are rarely systematic summaries on CDs with persistent luminescence. Here, a summary of the recent progress on persistent luminescent CDs, including luminous mechanism, synthetic strategies, property regulation, and potential applications, is given. First, a brief introduction is given to the development of CDs luminescent materials. Then, the luminous mechanism of afterglow CDs from room temperature phosphorescence (RTP), delayed fluorescence (DF), and long persistent luminescence (LPL) is discussed. Next, the constructed methods of luminescent CDs materials are summarized from two aspects, including matrix-free self-protected and matrix-protected CDs. Moreover, the regulation of afterglow properties from color, lifetime, and efficiency is presented. Afterwards, the potential applications of CDs, such as anti-counterfeiting, information encryption, sensing, bio-imaging, multicolor display, LED devices, etc., are reviewed. Finally, an outlook on the development of CDs materials and applications is proposed.     

Color-Tunable Polymeric Long-Persistent Luminescence Based on Polyphosphazenes

Organic long-persistent luminescence (OLPL) materials have attracted wide attention on account of their fascinating luminescence properties, presenting application prospects in the fields of bioimaging, information security, displays, anti-counterfeiting, and so on. Some effective strategies have been developed to promote the intersystem crossing (ISC) of the excited singlet state to triplet state and limit nonradiative transition, and thus OLPL materials with long lifetime (more than 1s) and high quantum yield have been explored. However, OLPL materials with dynamic and excitation-dependent characteristics are rarely reported. In this work, two novel polyphosphazene derivatives containing carbazolyl units are designed and synthesized successfully, and then they are doped into poly(vinyl alcohol) (PVA) films to achieve polymeric long-persistent luminescence (PLPL). Unexpectedly, excitation-dependent PLPL (ED-PLPL) is obtained under ambient conditions (in air at room temperature), and the persistent luminescence color can be changed from blue to green upon varying the excitation wavelength. At the same time, a dynamic cycle of ED-PLPL is realized based on the formation and destruction of hydrogen bonding interactions between the PVA chains and polyphosphazene phosphor. This work provides a new strategy for the design of color-tunable polymeric luminescent materials under ambient conditions.     

Eu掺杂KNN陶瓷的制备及可调性发光研究

稀土离子掺杂铁电陶瓷是一类新型光致变色材料, 在光开关、光信息存储等领域具有潜在应用价值。本研究采用水热法制备了(K_0.5 Na_0.5)_1-xEu_xNbO₃(KNN:xEu)前驱体粉体, 随后利用高温烧结得到对应陶瓷样品。在465 nm激发下, 观察到615 nm处有强的红色发光, 对应于Eu ³⁺的 ⁵D₀→ ⁷F₂跃迁。通过紫外光照射, KNN:Eu陶瓷从乳白色变为深灰色。随后经过200 ℃加热10 min, 着色陶瓷又变回到初始颜色, 显示出良好的光致变色行为。紫外照射和反复加热循环可以有效调控该陶瓷的发光强度。且经过多次循环之后, 发光强度没有明显衰减。在紫外光照射下, KNN:0.06Eu陶瓷发光强度的可调比(ΔR_t)高达83.9%, 说明发光具有良好的可调性。进而结合发光中心和色心之间的能量转移, 对KNN:Eu陶瓷的光致变色和发光机理进行了解释。     

A Fluorescence–Phosphorescence–Phosphorescence Triple‐Channel Emission Strategy for Full‐Color Luminescence

Organic luminogens constitute promising prototypes for various optoelectronic applications. Since gaining distinct color emissions normally requires the alternation of the conjugated backbone, big issues remain in material synthetic cost and skeleton compatibility while pursuing full‐color luminescence. Upon a facile one‐step coupling, three simple but smart perchalcogenated (O, S, and Se) arenes are synthesized. They exhibit strong luminescent tricolor primaries (i.e., blue, green, and red, respectively) in the solid state with a superior quantum yield up to >40% (5–10 times higher than that in corresponding solutions). The properties originate from a fluorescence–phosphorescence–phosphorescence triple‐channel emission effect, which is regulated by S and Se heavy atoms–dependent intersystem crossing upon molecular packing, as well as Se–Se atom interaction–caused energy splittings. Consequently, full‐color luminescence, including a typical white‐light luminescence with a Commission Internationale de I'Eclairage coordinate of (0.30, 0.35), is realized by complementarily incorporating these tricolor luminescent materials in the film. Moreover, mechanochromic luminescent color conversions are also observed to achieve the fine‐tuning of the luminescent tints. This strategy can be smart to address full‐color luminescence on the same molecular skeleton, showing better material compatibility as an alternative to the traditional multiple‐luminophore engineering.     

Energy Manipulation in Lanthanide-Doped Core–Shell Nanoparticles for Tunable Dual-Mode Luminescence toward Advanced Anti-Counterfeiting

Developing advanced luminescent materials and techniques is of significant importance for anti-counterfeiting applications, and remains a huge challenge. In this work, a new and efficient approach for achieving efficient dual-mode luminescence with tunable color outputs via Gd³⁺-mediated interfacial energy transfer, Ce³⁺-assisted cross-relaxation, and core–shell nanostructuring strategy is reported. The introduction of Ce³⁺ into the inner core not only serves the regulation of upconversion emission, but also facilitates the ultraviolet photon harvesting and subsequent energy transfer to downshifting (DS) activators in the outer shell layer. Furthermore, the construction of the core@shell nanoarchitecture enables the spatial separation of upconverting activators and DS centers, which greatly suppresses their adverse cross-relaxation processes. Consequently, efficient and multicolor-tunable dual-mode emissions can be simultaneously observed in the pre-designed NaGdF₄:Yb/Ho/Ce@NaYF₄:X (X = Eu, Tb, Sm, Dy) core–shell nanostructures under 254 nm ultraviolet light and 980 nm laser excitation. The proof-of-concept experiment demonstrates that 2D-encoded patterns based on dual-mode emitting nanomaterials are very promising for anti-counterfeiting applications. It is believed that this preliminary study will advance the development of the fluorescent materials for potential applications in anti-counterfeiting and optical multiplexing.     

Wide‐Range Tuning and Enhancement of Organic Long‐Persistent Luminescence Using Emitter Dopants

Most long‐persistent luminescent (LPL) materials, which slowly release energy absorbed from ambient light, are based on inorganic compounds. Organic long‐persistent luminescent (OLPL) systems have advantages over inorganic LPL materials in terms of solubility, transparency, and flexibility. Here, the characteristics of OLPL emission are improved by doping emitter molecules into an OLPL matrix. Greenish‐blue to red and even warm white emission are achieved by energy transfer from exciplex in the OLPL matrix to the emitter dopants. The dopants also improve brightness and emission duration through efficient radiative decay and the trapping of electrons, respectively. This technique will enable the development of a wide range of organic glow‐in‐the‐dark paints.     

Temporal and Remote Tuning of Piezophotonic‐Effect‐Induced Luminescence and Color Gamut via Modulating Magnetic Field

Light‐emitting materials have been extensively investigated because of their widespread applications in solid‐state lighting, displays, sensors, and bioimaging. In these applications, it is highly desirable to achieve tunable luminescence in terms of luminescent intensity and wavelength. Here, a convenient physical approach of temporal and remote tuning of light‐emitting wavelength and color is demonstrated, which is greatly different from conventional methods. It is shown that by modulating the frequency of magnetic‐field excitation at room temperature, luminescence from the flexible composites of ZnS:Al, Cu phosphors induced by the piezophotonic effect can be tuned in real time and in situ. The mechanistic investigation suggests that the observed tunable piezophotonic emission is ascribed to the tilting band structure of the ZnS phosphor induced by magnetostrictive strain under a high frequency of magnetic‐field excitation. Furthermore, some proof‐of concept devices, including red–green–blue full‐color displays and tunable white‐light sources are demonstrated simply by frequency modulation. A new understanding of the fundamentals of both luminescence and magnetic–optics coupling is thus provided, while offering opportunities in magnetic–optical sensing, piezophotonics, energy harvesting, novel light sources, and displays.     

发光波长可调的聚吡咯甲烷的制备及光学特性

聚合物发光材料因其拥有诸多优点,在有机发光二极管器件方面的应用前景广阔.然而,对于蓝光聚合物发光材料,由于其发光性能、使用寿命等方面仍然存在不足,难以满足全色显示的需要.以吡咯类单体和4-乙基苯甲醛单体为原料,采用溶液缩聚法制备了3种聚吡咯甲烷(聚{吡咯-[2,5-二(4-乙基苯甲烷)]}(PPE)、聚{N-甲基吡咯-...     

新型彩色长余辉材料的制备及其发光性能的研究

将红色染料罗丹明B与绿色长余辉材料混配间接获得可被可见光激发的橙红色长余辉材料,并在此基础上根据三基色原理得到了一系列彩色长余辉发光材料,同时对其发光性能进行了系统研究.通过对材料的余辉谱以及余辉曲线分析,发现随着加入的蓝、绿色长余辉材料与罗丹明B相对浓度的变化,其位于510和580nm左右的余辉光谱特征峰分别发生一定...