可见光长余辉材料的设计合成及其余辉特性的研究

发布时间：2018-01-05 11:16

本文关键词：可见光长余辉材料的设计合成及其余辉特性的研究　出处：《兰州大学》2016年博士论文　论文类型：学位论文

【摘要】：长余辉发光材料因其在弱光紧急照明等领域的广泛应用而受到人们关注。随着长余辉材料的不断发展,人们对长余辉材料的余辉性能及颜色提出更高的要求。同时长余辉发光机理尚未取得共识。针对上述问题,设计合成了多种可见光长余辉材料,并系统研究其发光、余辉特性。本论文主要涉及以下几个方面内容:一.采用分离陷阱中心和发光中心在不同基质,利用Ca Al2O4:Eu2+,Nd3+(CA)优越的储能能力和Y3Al5O12:Ce3+(YAG)高效的黄光发射的特点,制备了CA/YAG复合长余辉材料,通过辐射能量传递方式实现了余辉颜色从蓝到黄可调,复合样品的余辉时间较纯CA的有很大提高,由原来的19h达到48h,提高到原来的2.8倍。复合样品的余辉初始亮度也得到提高,达到3200 mcd/m2,提高到原来的2.7倍,复合样品余辉性能提高可能是YAG的500nm到700nm的宽带发射光激励CA中的深陷阱,使其释放深陷阱中的载流子,与热扰动下释放的载流子共同对余辉起作用。同时,YAG把CA发出的蓝光转换为黄光时,虽然辐射量Φe(λ)降低,但是由于黄光的光视效率V(λ)要比蓝光的要高很多,综合的结果就是复合样品的余辉亮度提高,余辉时间增长。采用该方法制备的白色长余辉材料余辉时间达到45h,克服三基色复合得到白色长余辉材料要求衰减、强度和激发波长一致的两个难点。二.单一基质余辉可调:采用高温固相法制备了蓝色到白色可调的新型长余辉材料(Ca0.65-xSr0.35-x)7(Si O3)6Cl2:Eu3+x,Tm3+x(0.01≤x≤0.08),获得蓝色长余辉材料余辉时间达27h,初始亮度1275mcd/m2。白色余辉材料余辉时间超过22h,比目前最长的白色余辉Cd Si O3:Dy3+要长17h。热释光曲线表明共掺Tm3+后引入了三个深度不同深度的陷阱中心,分别由Tm3+替代不同格位上的阳离子所产生的缺陷聚集而成,即:[Tm·sr],[Tm·Ca-Tm·sr],[Tm·Ca]。通过分析衰减不同时间热释光曲线表明,[Tm·sr],对余辉起主导作用,[Tm·Ca-Tm·sr]和[Tm·Ca]在室温下难以释放。通过研究不同温度下的余辉光谱,证明陷阱的非随机分布。由于[Tm·sr]离Eu1近,更易捕获来自Eu1的电子,[Tm·Ca-Tm·sr]离Eu2近,所以易捕获Eu2的电子。[Tm·Ca]离两个发光中心的距离相当,所以捕获概率相差不大。对比不同激发源下的热释光曲线表明,254nm激发下,电子被激发到导带,然后,电子再被陷阱捕获。365nm激发下,电子被激发到Eu2+激发态,随后直接通过遂穿到陷阱能级。三.开发了新型蓝色长余辉材料Ca3Al2O6:Ce3+、绿色长余辉材料Sr3Al2O5Cl2:Tb3+、黄色长余辉材料Ba3P4O13:Eu2+,Ga3+、橙色长余辉材料Ca3Si O4Cl2:Eu2+,R3+(R=Dy,Ce,Nd)、红色长余辉材料Ca4(PO4)2O:Eu2+,R3+(R=Y,Tm,Ce,Gd,La,Lu),拓宽了基质和激活剂的选择。合成了Ce3+掺杂的Ca3Al2O6的系列样品,发射光谱为400nm到600nm的非对称宽带发射,发射主峰在485nm,归属于Ce3+占据Ca3Al2O6中2个不同Ca离子格位所引起5d→4f跃迁发射。热释光曲线表明33℃的热释峰所对应的陷阱对长余辉有直接的关系。合成了绿色长余辉材料Sr3Al2O5Cl2:Tb3+,最佳余辉时间达1h。通过改变激发时间,发现绿色长余辉材料Sr3Al2O5Cl2:Tb3+中不同深度陷阱的填充规律。在黄色长余辉材料Ba3P4O13:Eu2+发现共掺非稀土Ga3+对余辉性能提升起重要作用,余辉时间达8.5h,而共掺稀土离子并不能有效提高余辉性能,甚至反而降低了余辉时间。该研究拓展了共掺离子的选择。开发了新型近橙色长余辉发光材料Ca3Si O4Cl2:Eu2+,R3+(R=Dy,Ce,Nd)。系列样品在380nm激发下呈现主峰在615nm的一个宽带发射。单掺Eu2+样品余辉只有2min,共掺稀土离子Dy,Ce,Nd使得样品余辉性能提高,效果最好的是共掺Dy,余辉时间达到40min。合成了新型近红外长余辉发光材料Ca4(PO4)2O:Eu2+,R3+(R=Y,Tm,Ce,Gd,La,Lu)。系列样品在467nm激发下呈现主峰在690nm的一个宽带发射。共掺稀土离子Y,Tm,Ce,Gd,La,Lu均有余辉,Eu2+,Y3+共掺的余辉时间最长,可达2h。这种新型的红长余辉发光材料拓宽了基质和激活剂的选择。
[Abstract]:Long afterglow materials attracted attention because of the wide application in the weak light of emergency lighting and other fields. With the continuous development of long afterglow materials, afterglow properties and color of long afterglow materials put forward higher requirements. At the same time long afterglow mechanism has not yet been agreed. Aiming at the above problems, the design and synthesis of a variety of visible light long afterglow materials, and systematically study the light, afterglow characteristics. This paper mainly involves the following several aspects: 1. The separation of trap center and luminescence centers in different matrix, using Ca Al2O4:Eu2+ Nd3+ (CA) superior energy storage capacity and Y3Al5O12:Ce3+ (YAG), yellow light emission characteristics of CA/YAG composite the afterglow materials were prepared, the afterglow color from blue to yellow can be adjusted by radiation energy transfer, afterglow time of composite samples was higher than pure CA has greatly improved, from 19h to 48h, improve To the original 2.8 times. The afterglow initial brightness composite sample is also improved, reached 3200 mcd/m2, increased to 2.7 times the original, composite luminescent performance improvement may be YAG to 700nm 500nm broadband emission light excitation deep traps in CA, the release of carriers in deep traps, and the release of heat carrier disturbance under the common role of Yu Huiqi. At the same time, YAG put the blue light from the CA converted to yellow light, although the amount of radiation with E (lambda) decreased, but due to the yellow light luminous efficiency V (lambda) to be much higher than the blue, comprehensive is the result of the composite sample to improve the brightness, afterglow time growth. The preparation method of the white long afterglow afterglow time reached 45h, overcome three color composite white long afterglow materials require attenuation, intensity and excitation wavelength of two points consistent. Two. Single matrix afterglow adjustable: the high temperature solid phase method Blue to white adjustable new long afterglow materials were prepared (Ca0.65-xSr0.35-x) 7 (Si O3) 6Cl2:Eu3+x, Tm3+x (x = 0.01 ~ 0.08), get the blue long afterglow materials afterglow time of 27h, the initial brightness white 1275mcd/m2. afterglow afterglow time is more than 22h, than the long white Cd Si O3:Dy3+ long afterglow 17h. thermoluminescence curves show that Co doped Tm3+ after the introduction of the three depth of trap center, shortcomings were replaced by Tm3+ cation on different sites have gathered together, namely: [Tm, sr], [Tm, Ca-Tm, sr], [Tm and Ca].. Through the analysis of different attenuation time thermoluminescence curves show that [Tm, sr], the leading role of Yu Huiqi, [Tm Ca-Tm sr] and [Tm Ca] to release at room temperature. Through the study of afterglow spectra under different temperatures, non random distribution of proof trap. Because the [Tm sr] near Eu1, more easily capture electrons from Eu1, [Tm Ca-Tm. Sr] closer to Eu2, so easy to capture Eu2.[Tm Ca] from the two electronic luminescence center distance, so the capture probability difference. Comparing the different excitation sources under the thermoluminescence curves show that under 254nm excitation, electrons are excited into the conduction band, then, is electron trap under the excitation of.365nm, electrons are excited to the Eu2+ excited state, followed by tunneling to trap energy directly. Three. The development of a new type of blue long afterglow materials Ca3Al2O6:Ce3+, Sr3Al2O5Cl2:Tb3+ yellow green long afterglow materials, long afterglow materials Ba3P4O13:Eu2+, Ga3+, orange long afterglow phosphor Ca3Si O4Cl2:Eu2+, R3+ (R=Dy, Ce, Nd), red phosphor Ca4 (PO4) 2O:Eu2+, R3+ (R=Y, Tm, Ce, Gd, La, Lu), broaden the substrate and activator. The samples with Ce3+ doped Ca3Al2O6 was synthesized, the emission of 400nm to asymmetric broadband 600nm, emission peak at 485nm, belonging to Ce3+ occupy C A3Al2O6 in 2 different Ca ion site caused by emission 5D to 4f transition. The thermoluminescence curve shows that 33 degrees of pyroelectric peaks corresponding to the trap has a direct bearing on the long afterglow. Green long afterglow phosphor Sr3Al2O5Cl2:Tb3+ was synthesized, the best afterglow time of 1h. by changing the excitation time, the different depth of trap green long afterglow in Sr3Al2O5Cl2:Tb3+ filling rule. Found Co doped rare earth Ga3+ on non afterglow properties play an important role in the promotion of yellow long afterglow phosphor Ba3P4O13:Eu2+, afterglow time of 8.5H and Co doped rare earth ions and can effectively improve the afterglow properties, but reduces the afterglow time. Even the study extends the selection of doped metal ions. The development of the a new near orange phosphor Ca3Si O4Cl2:Eu2+, R3+ (R=Dy, Ce, Nd). A series of samples showed a peak in the broadband 615nm emission under the excitation of 380nm doped Eu2+ samples. Only Yu Hui 2min, Co doped rare earth ions Dy, Ce, Nd improves the luminescent performance, is the best effect of Co doped Dy, the afterglow time reached 40min. synthesis of new near infrared luminescent materials Ca4 (PO4) 2O:Eu2+, R3+ (R=Y, Tm, Ce, Gd, La, Lu). A series of samples showing peak in a broadband 690nm emission in 467nm Co doped rare earth ions under excitation. Y, Tm, Ce, Gd, La, Eu2+, Lu have the afterglow, the afterglow time of Y3+ Co doped 2h. was the longest, the red long afterglow luminescent material model broadens the matrix and activator.

【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O482.31

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