长余辉发光材料研究进展

90年代发现和发展起来的铝酸盐体系长余辉发光材料是一类重要的新 型能源材料和节能材料。本文主要综述了最近几年来铝酸盐体系中长人科辉发光研究进展。指出了氧化物体系长余辉发光材料的特点和优势,总结了新型长余辉发光材料的基质和激活剂种类、性质及其对稀土 离子 长余辉发光性能的影响和作用,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。     

稀土红色长余辉发光材料研究进展

综述了稀土元素掺杂红色长余辉发光材料的研究进展，总结了硫化物、钛酸盐、硫氧化物、硅酸盐、氧化物和磷酸盐等基质体系的红色长余辉发光，并指出硫氧化物和磷酸盐等基质是最具有发展前景的红色长余辉发光体系，讨论了Eu^2 在硫化物、Pr^3 在钛酸盐以及Eu^3 和Sm^3 等稀土离子在硫氧化物和硅酸盐等体系中的红色长余辉发光机制。介绍了传统的高温固相法以及溶胶．凝胶法、微波合成法等稀土红色长余辉材料的制备技术。提出了从基质材料、制备技术和稀土离子发光机制入手是稀土红色长余辉发光材料今后研究与开发的发展方向。     

长余辉发光材料在陶瓷行业的应用研究

长余辉发光材料和陶／搪瓷材料的结合始于80年代,当时采用的是传统的硫化物体系长余辉发光材料。20世纪90年代,随着多种新型长余辉材料的发现,使性能更佳的长余辉陶／搪瓷制品的开发成为可能。本文介绍新型铝酸盐体系、硅酸盐体系及新型红色长余辉材料应用于低温陶／搪瓷釉料（800－900℃）、中温陶瓷釉料（980－1100℃）,及将低温陶／搪瓷釉料、中温陶瓷釉料应用于陶／搪瓷制品的研究,以及将各种新型长余辉材料应用于花纸、玻璃行业中。这种长余辉陶／瓷制品性能稳定、发光强度达到发光粉的80％,发光时间可达12h以上;而且应用工艺简单,可直接用传统的陶／搪瓷制品工艺进行生产。     

激活CaO-MgO-SiO_2长余辉玻璃发光性质

报道了一种新型的Eu~(2+)离子激活硅酸盐玻璃,该玻璃组成为2CaO-MgO-3SiO_2-0.015Eu_2O_3(CMSE)。通过透射光谱、稳态荧光光谱、余辉光谱和热释光等技术手段对CMSE的发光性质进行了深入研究。研究发现CMSE可以被紫光和近紫外光激发,获得黄色长余辉发光。热释光曲线的分析表明,CMSE的长余辉性质主要来自于玻璃基质中陷阱深度为0.83 e V左右的定域能级。研究认为对CMSE发光性质的研究有利于开发新型稀土离子激活近紫外激发LED用硅酸盐玻璃发光材料。     

pH值对硅烷偶联剂表面改性稀土长余辉发光材料的影响

为提高稀土长余辉发光材料SrMgAl4 O8:Eu2+,Dy3+在非极性树脂中的分散性和相容性,用硅烷偶联剂YDH-570在强酸条件下对其进行了表面改性.通过质量变化、比表面积、ATR-FTIR、SEM(能谱分析)和发光性能分别研究了该条件下不同ptH值改性对材料表面组成、形貌和性能的影响.结果发现:强酸条件下改性效果十分显著;当pH值由0.6增加到0.72时,样品增重率达23.3％,33.3％,53.3％,比表面积净增75.6％,215.2％,265.4％;对于改性效果较明显的pH为0.72的样品,能谱分析证实是一种片状有机包覆层结构;余辉衰减曲线表明,表面改性对材料发光性能影响不大.     

长余辉发光玻璃SrAl2O4∶Dy, Eu的制备与发光性能研究

在低熔点破璃中掺杂一定量的长余辉发光粉制备了性能优良的长余辉发光玻璃。在保证发光玻璃均匀透明的基础上，发光性能随发光粉掺杂量的增加而增强，尽量降低假烧温度和减少保温时间可以保持良好的发光性能，在还原气氛制备的发光玻璃性能优于在空气中制备的。煅烧工艺对发光玻璃的微观结构有显著的影响。     

ZnO-B2O3∶Tb3+长余辉玻璃的发光性质

通过还原方法制备了Tb3+离子掺杂的硼酸锌玻璃,并观察到在254 nm紫外光激发后有明亮的绿色长余辉发光现象,余辉时间达6 h.通过激发与发射光谱、余辉光谱、余辉衰减曲线、热释光谱、热释光释出速率衰减曲线等得到的信息,研究了Tb3+离子掺杂的硼酸锌玻璃的发光性质.     

用两种方法合成长余辉发光玻璃的对比研究

在还原性气氛下高温固相反应法（一步法）合成了长余辉发光玻璃GA；用SrAl2O4:Eu,Dy荧光粉（SAED）与玻璃粉混合高温熔融（二步法）合成了长余辉发光玻璃GB和GC，通过XRD，发光光谱和磷光衰减曲线对样品进行了表征，荧光粉SAED和玻璃GA，GB，GC的发射峰值依次是525，493。462，516nm，发光强度和余辉时间都是SAED＞GC＞GB＞GA，玻璃的发射光谱峰随玻璃组成不同发生位移，两种发生合成的夜光玻璃发光性质存在明显的差异，同一合成方法下，玻璃基料决定着玻璃网络结构，同时也影响着夜光玻璃的发光性质。     

长余辉碳点材料研究进展

长余辉材料因其特殊的发光效果而广受关注,但现有长余辉体系普遍存在成本高、工艺烦琐等问题,因此构筑廉价高效的新型余辉材料体系成为主流趋势.碳点是近年来发展迅速的荧光纳米碳材料之一,除其荧光特性广受重视之外,以室温磷光(RTP)、热活化延迟荧光(TADF)为主的余辉特性也引起广大科研工作者的关注.综合碳点低成本、低毒且制备...     

Long Lasting Phosphorescence Properties and Multi-peak Fitting on Thermoluminescence of Red LaAlO3: Eu3+ Phosphor

Red long lasting phosphorescence(LLP) was firstly observed in LaAlO₃:Eu³⁺ phosphor synthesized by solid state method at 1773 K. It reveals that the Eu³⁺ ions occupy the asymmetric La³⁺ sites, resulting in the orange-red emission of Eu³⁺. The LLP of the optimum LaAlO₃:0.6%Eu³⁺ sample can come to about 2000 s according to a definition of 0.32 mcd/m². The LLP decay curve can not be fitted even by a function of three exponential terms, due to the complicated retrapping process of carriers. The result of a classical multi-peak fitting method on thermoluminescence reveals that the excellent LLP performance of LaAlO₃:Eu³⁺ material originates from the rich distribution of shallow traps(E=0.7875 eV).     

Long Afterglow Room‐Temperature Phosphorescence from Nanopebbles: A Urea Pyrolysis Product

Materials having long afterglow are highly sought after for various applications such as light‐emitting diodes, security signs and bioimaging. Herein, we report a simple, low‐cost synthesis of a purely organic room‐temperature phosphorescent nanomaterial with a pebble‐like structure by heating urea, a biocompatible and easily available precursor, at 200 °C with a high phosphorescence lifetime of 1.0365 s and a visible afterglow for up to 10 s. This urea derived phosphorescent nanocomposite (UPNC) can be mixed with commercially available acrylic paint base and common gum, which can be readily used as a phosphorescent pigment.     

Manipulation of Triplet Excited States in Two-Component Systems for High-Performance Organic Afterglow Materials

The past several years have witnessed the tremendous development of novel chemical structures, new design strategies and intriguing applications in the field of room-temperature phosphorescence (RTP) and organic afterglow materials. This Review article focuses on recent advancements of high-performance organic afterglow materials obtained by two-component design strategies such as a dopant-matrix, donor–acceptor, sensitization, and energy-transfer strategies. Based on some cutting-edge studies, organic afterglow efficiency has been largely improved, exceeding 90 % in several cases. Organic afterglow durations reach tens of seconds in phosphorescence systems and hours in donor–acceptor systems. Organic afterglow brightness outcompetes some inorganic afterglow materials in the first several seconds after ceasing excitation source. Organic afterglow colors cover the whole visible regions and extend to near-infrared regions with respectful afterglow efficiency. On the basis of these achievements, researchers demonstrate promising applications of organic afterglow materials in diverse fields, which has also been reviewed.     

蓝紫色ZnO-Al2O3-SiO2长余辉陶瓷

通过高温固相法首次合成并报道了兰紫色ZnO-Al2O3-SiO2长余辉陶瓷，系统地研究了其发光和缺陷性质，在强度0.6mW.cm^-2，主峰254nm的UVP紫外灯下激发15min，然后关闭激发源，样品发射兰紫色长余辉，撤去激发源以后5s，余辉初始强度为230mcd.m^-1，色坐标为（0．1292，0．0984），暗视场中，8h以后余辉仍然肉眼可辨，样品的紫外可见发射和不同时间的余辉发射光谱显示，荧光发射位于390nm，来源于基质的自致发光，而余辉有两个发射峰，主峰位于390nm，肩峰位于520nm，这表明样品中存在两种余辉发射中心，由余辉衰减曲线可以看出，这两种余辉发光都由一个快过程和一个慢过程组成，其中，慢过程决定了材料的长余辉时间，从时间依赖的余辉强度倒数曲线可以看出，余辉强度与时间成反比，这表明余辉发光的机理为电子空穴复合过程，热释光谱显示，样品分别在92和250℃附近出现两个宽的热释峰，说明材料中至少存在两种具有不同陷阱深度的电子或空穴缺陷中心。     

喷雾热解法制备球形SrAl_2O_4:Eu,Dy长余辉发光材料

采用喷雾热解两段法制备了SrAl2O4:Eu,Dy长余辉发光材料,利用SEM、荧光长余辉亮度测试、F-4500荧光分光光度等方法分析了不同制备工艺条件下SrAl2O4:Eu,Dy发光材料的形貌、余辉性能以及光谱性能的变化。采用喷雾热解两段法可制备出余辉性能良好的球形SrAl2O4:Eu,Dy长余辉发光材料。前驱体溶液浓度、热解温度、添加剂对产物的形貌、粒度分布、发光性能有较大影响。较之高温固相法,喷雾热解法制备的SrAl2O4:Eu,Dy具有合成温度低、发光性能好、形貌好、粒度分布窄等优点。     

Y2O2S:Eu,Ti,Mg的光谱性质和长时发光特性

研究了Ti, Mg, Eu等离子掺杂的Y2O2S材料的光谱性质和长时发光特性, 并发现了光致激发下Y2O2S∶Ti中峰值为594nm的宽带发射及长时发光现象. 根据发射光谱和衰减曲线的分析, 认为Ti掺杂后在Y2O2S晶体中形成施主能级, 有效地捕获离化的电子, 造成长时发光现象. 共掺入Mg进行电荷补偿可增强初始发光亮度和发光时间. 在红色长时发光材料Y2O2S∶Eu, Ti, Mg中, Eu3 作为发光中心, 接受被俘获的电子和空穴重新复合后释放的能量, 发射Eu3 的626和616 nm等特征光谱.     

Alcohol‐Soluble Electron‐Transport Materials for Fully Solution‐Processed Green PhOLEDs

Two alcohol‐soluble electron‐transport materials (ETMs), diphenyl(4‐(1‐phenyl‐1H‐benzo[d]imidazol‐2‐yl)phenyl)phosphine oxide (pPBIPO) and (3,5‐bis(1‐phenyl‐1H‐benzo[d]imidazol‐2‐yl)phenyl)diphenylphosphine oxide (mBPBIPO), have been synthesized. The physical properties of these ETMs were investigated and they both exhibited high electron‐transport mobilities (1.67×10^?4 and 2.15×10^?4 cm² V^?1 s^?1), high glass‐transition temperatures (81 and 110 °C), and low LUMO energy levels (?2.87 and ?2.82 eV, respectively). The solubility of PBIPO in n‐butyl alcohol was more than 20 mg mL^?1, which meets the requirement for fully solution‐processed organic light‐emitting diodes (OLEDs). Fully solution‐processed green‐phosphorescent OLEDs were fabricated by using alcohol‐soluble PBIPO as electron‐transport layers (ETLs), and they exhibited high current efficiencies, power efficiencies, and external quantum efficiencies of up to 38.43 cd A^?1, 26.64 lm W^?1, and 10.87 %, respectively. Compared with devices that did not contain PBIPO as an ETM, the performance of these devices was much improved, which indicated the excellent electron‐transport properties of PBIPO.