温度、pH对含油污水荧光特性的影响

研究了中石化炼油厂出口处含油污水在温度5～55℃,pH 3～12范围内的荧光光谱特性.结果表明,温度只对含油污水的荧光强度有影响,而不改变荧光峰位置;在酸性条件下荧光峰右移,从413 nm移到426.5 nm;且荧光强度随酸性增强而递增.碱性条件下随着碱性增强荧光强度降低,但荧光峰的位置没有移动,始终保持在398 nm...     

六方单晶氮化铝薄膜的合成与紫光发光机理

利用无水三氯化铝与叠氮化钠在无溶剂的条件下直接反应,成功地合成出六方单晶氮化铝(h-AlN)薄膜.反应温度为450℃,有效反应时间为20 h.高分辨率透射电镜发现为薄膜形态；电子衍射和X射线衍射结果都表明,氮化铝薄膜为六方结构.光致发光实验显示,在可见光范围内有一较强的辐射峰,中心位于413 nm处,半高宽约为5 nm.同时,本文对六方单晶氮化铝薄膜的生长机理和光致发光机理也进行了讨论.     

退火对He注入及随后208 Pb27+辐照的Al2O3单晶PL谱的影响

利用高能离子研究了110 keV的He+注入Al2O3单晶及随后230 MeV的208pb27+辐照并在不同温度条件下退火样品的光致发光的特性.从测试结果可以清楚地看到在375 nm,390 nm,413 nm和450 nm出现了强烈的发光峰.经过600 K退火2 h后测试结果显示,390 nm发光峰增强剧烈,而别的发光峰显示不明显.在900 K退火条件下,390 nm的发光峰开始减弱相反在510 nm出现了较强的发光峰,到1100 K退火完毕后390 nm的发光峰完全消失,而510 nm的发光峰相对增强.从辐照样品的FTIR谱中看到,波数在460-510 cm-1间的吸收是振动模式,经过离子辐照后,吸收带展宽,随着辐照量的增大,Al2O3振动吸收峰消失,说明Al2O3振动模式被完全破坏.1000-1300cm-1之间为Al-O-Al桥氧的伸缩振动模式,辐照后吸收带向高波数方向移动.退火后的FTIR谱变化不大.     

铋/铒共掺光纤荧光特性实验研究

分别用980nm和830nm的半导体激光器作为泵浦源激发铋/铒共掺光纤,采用前向和背向泵浦方式分析放大的自发辐射谱特性.实验结果表明:随着泵浦功率的增大,荧光强度显著增强.利用980nm半导体激光器,采用前向泵浦方式可激发以1 142nm和1 536nm为中心的两个辐射带,以1 142nm为最高辐射峰的3dB带宽是141nm,以1 536nm为最高辐射峰的3dB带宽是29nm.利用830nm半导体激光器,采用前向泵浦方式可激发以1 421nm为中心的荧光谱,3dB带宽是447nm.980nm和830nm激光器分别前向泵浦铋/铒共掺光纤时,随着光纤长度的增加,荧光先增强后减弱;分别背向泵浦铋/铒共掺光纤时,随着光纤长度的增加,荧光强度先逐渐增强后保持稳定.在25~80℃的温度范围内,铋/铒共掺光纤的荧光强度几乎不受温度的影响.使用980nm和830nm泵浦源同时激发铋/铒共掺光纤,结果表明铋/铒共掺光纤的发光中心具有相对独立性,发光范围存在部分重叠.     

染料掺杂聚合物分散胆甾相液晶薄膜激光特性研究

采用激光染料DCM、向列相液晶TEB30A、手性剂S-811、聚乙烯醇(PVA), 通过微胶囊法制备了聚合物分散胆甾相液晶薄膜, 测量激光辐射谱, 研究了其激光辐射机理和温度调谐特性. 利用正交偏光显微镜观察器件织构, 看到液晶微滴分散均匀, 尺寸较大, 约为80 μm, 并且微滴中液晶分子呈现平面态排列织构. 以532 nm的Nd:YAG固体激光器作为抽运源, 测得在634.5 nm和680.2 nm波长处出现了尖锐的激光辐射峰, 线宽分别约为0.25 nm, 0.29 nm. 并与染料掺杂胆甾相液晶激光器件进行比较. 升高器件温度, 其输出激光波长蓝移, 获得666.7 nm至643.9 nm共22.8 nm的调谐范围. 由实验结果分析得出, 激光辐射机理为光子禁带末端激光, 出射波长分别对应光子禁带的两个边沿.     

蒽芘混合溶液二维荧光相关谱解析

采用二维荧光相关光谱技术有效地对严重重叠的蒽、芘混合溶液的荧光峰进行解析。为了实现上述研究目标,设计并配置了9个蒽、芘混合溶液。采集了蒽、芘单组份以及两种物质混合溶液的常规一维荧光谱,研究了其荧光特性,并进行对比、分析。在此基础上,以混合溶液中蒽和芘的浓度为外扰,构建二维荧光相关同步谱和异步谱。结果表明:在同步谱上出现6个较强的自相关峰,位置分别在373nm、379nm、391nm、401nm、413nm和425nm处;依据未被覆盖的蒽在425nm的处荧光与各波长处荧光交叉峰的正负,指出379nm、401nm和452nm处的荧光峰来自蒽,而373nm、391nm和413nm处的荧光峰来自芘。同时,又根据相关异步谱交叉峰的有无,进一步确认和验证了混合溶液中各荧光峰的来源。该方法为解析农业环境中多种污染物的光谱特征提供理论和实验基础。     

镓置换铝对SrAl2Si2O8∶Eu2+晶体结构和发光特性的影响

采用高温固相法在弱还原气氛下制备了Sr0.955Al2－xGaxSi2O8∶Eu2+ (x=0～1.0)系列荧光粉,研究了Ga3+置换铝Al3+对晶体结构和光谱特性的影响.Ga3+进入SrAl2Si2O8晶格与Al3+发生类质同相替代使晶胞参量a、b、c、β和晶胞体积V都随Ga3+置换量呈线性增大,表明形成了连续固溶体.镓置换铝对晶胞参量c的影响最明显,b其次,a最小.Eu2+的宽带激发光谱位于230～400 nm,表观峰值位于350 nm,可由267 nm、305 nm、350 nm和375 nm四个峰拟合而成.随着镓置换量增加,较短波长的三个激发峰发生红移并且267 nm和350 nm峰强度减弱,305 nm峰强度明显增强,375 nm峰位和强度基本不变,表观激发峰半高宽由109 nm减小至98 nm,基本不随镓置换量变化.发射光谱位于380～600 nm为不对称宽带,可由406 nm和441 nm两峰拟合而成并且随Ga3+置换量增加线性红移,拟合发射光谱峰面积之比线性递增,Ga3+进入晶格对较长波长发射中心影响较大.Ga3+置换量为1.0 mol时,表观发射峰位从407 nm线性红移至422 nm,表观峰值随Ga3+置换量线性增大,半高宽由58 nm增加至79 nm.镓置换铝造成Eu-O距离变小,发光中心Eu2+所处晶体场增强,5d轨道能级分裂变大,最低发射能级下移.     

退火对He注入及随后208Pb27+辐照的Al2O3单晶PL谱的影响

利用高能离子研究了110 keV 的He⁺注入Al₂O₃单晶及随后230 MeV的²⁰⁸Pb²⁷⁺辐照并在不同温度条件下退火样品的光致发光的特性. 从测试结果可以清楚地看到在375 nm，390 nm，413 nm 和450 nm 出现了强烈的发光峰. 经过600 K退火2 h后测试结果显示，390 nm发光峰增强剧烈，而别的发光峰显示不明显. 在900 K退火条件下，390 nm的发光峰开始减弱相反在510 nm出现了较强的发光峰，到1100 K退火完毕后390 nm的发光峰完全消失，而510 nm的发光峰相对增强. 从辐照样品的FTIR谱中看到，波数在460—510 cm^-1间的吸收是振动模式，经过离子辐照后，吸收带展宽，随着辐照量的增大，Al₂O₃振动吸收峰消失，说明Al₂O₃振动模式被完全破坏. 1000—1300 cm^-1之间为Al-O-Al桥氧的伸缩振动模式，辐照后吸收带向高波数方向移动. 退火后的FTIR谱变化不大.     

退火对非故意掺杂4H-SiC外延材料386 nm和388 nm发射峰的影响

10 K条件下,采用光致发光(PL)技术研究了不同退火处理后非故意掺杂4H-SiC外延材料的低温PL特性.结果发现,在370—400 nm范围内出现了三个发射峰,能量较高的峰约为3.26 eV,与4H-SiC材料的室温禁带宽度相当.波长约为386 nm和388 nm的两个发射峰分别位于~3.21 eV和~3.19 eV,与材料中的N杂质有关.当退火时间为30 min时,随退火温度的升高,386 nm和388 nm两个发射峰的PL强度先增加后减小,且退火温度为1573 K时,两个发射峰的PL强度均达到最大. 关键词： 光致发光 退火处理 能级 4H-SiC     

光动力学疗法新型光敏剂的光谱特性研究

实验研究了用于光动力学诊断和治疗的新型光敏剂二磺基二邻苯二甲酰亚胺甲基酞菁锌（ZnPcS2P)癌光啉（PsD-007)、血啉甲醚（HMME）以及早期应用于临床的血卟啉衍生物（HpD)分别在生理盐水和含10％人血清生理盐水中的光谱特性。结果表明：除ZnPcS2P2的最大吸收峰位于670nm之外，其余三种光敏剂在人血清环境中的最大吸收峰都位于405nm处，但与生理盐水环境相比索瑞（Soret)峰发生了12nm的红移。在波长为413和514.5nm光源激发下，HMME，HpD和PsD-007在人血清环境中的荧光发射峰都分别位于625和690nm，但413nm光源的激发效率比514.5nm光源高出3倍左右，而且HEEM的荧光激发效率最高，HpD次之，PsD-007最低。     

氮化铝铬的制备及其光学性质

利用直接氮化法得到了氮化铝和氮化铬,并用两种途径得到Cr³⁺掺杂的氮化铝样品。用X射线衍射仪分析了样品晶相并测试了两种样品的激发和发射光谱,计算了晶体场劈裂参数D_q和Racah参数B及D_q/B分别为1 800,693.69和2.59。光谱数据表明,Cr³⁺在氮化铝中属于强场环境,光发射来自于最低激发态²E能级,与在氧化铝中的环境相似。根据光谱数据给出了Cr³⁺在氮化铝晶体场中的能级。     

Effect of high-temperature annealing on AlN thin film grown by metalorganic chemical vapor deposition

The effect of high-temperature annealing on AlN thin film grown by metalorganic chemical vapor deposition was investigated using atomic force microscopy, Raman spectroscopy, and deep ultra-violet photoluminescence(PL) with the excitation wavelength as short as ～ 177 nm. Annealing experiments were carried out in either N2 or vacuum atmosphere with the annealing temperature ranging from 1200℃ to 1600℃. It is found that surface roughness reduced and compressive strain increased with the annealing temperature increasing in both annealing atmospheres. As to optical properties,a band-edge emission peak at 6.036 eV and a very broad emission band peaking at about 4.7 eV were observed in the photoluminescence spectrum of the as-grown sample. After annealing, the intensity of the band-edge emission peak varied with the annealing temperature and atmosphere. It is also found that a much stronger emission band ranging from 2.5 eV to 4.2 eV is superimposed on the original spectra by annealing in either N2 or vacuum atmosphere. We attribute these deep-level emission peaks to the VAL–ONcomplex in the AlN material.     

AlN微晶棒的的制备及光致发光性能研究

采用直流电弧放电方法,在无催化剂的条件下直接氮化Al合成纤锌矿结构的AlN微晶棒。分别利用拉曼光谱仪(Raman)、扫描电子显微镜(SEM)和光致发光(PL)谱等测试手段对所制备样品进行表征和发光性能的研究。结果表明:所制备的Al N微晶棒长度约为30μm,直径约为10μm。在AlN微晶棒的PL谱中,有两个主要发光峰,中心在430 nm的发射源于VN和(V_(Al)-O_N)~(2-)构成的深施主-深受主对缺陷发光,中心在650 nm的发射源于VAl形成的深受主能级到价带的缺陷发光。在激发波长由270 nm逐渐增大到300 nm的过程中发现,Al N微晶棒波长在430 nm处的发光峰先增强后减弱,在激发波长为285 nm时强度最大;650 nm处的发光峰随激发波长增大而逐渐增强。     

White light emission from Er,Pr co-doped AlN films

In this work, Er-doped aluminum nitride(AlN), Pr-doped AlN, and Er, Pr co-doped AlN thin films were prepared by ion implantation. After annealing, the luminescence properties were investigated by cathodoluminescence. Some new and interesting phenomena were observed. The peak at 480 nm was observed only for Er-doped AlN. However, for Er, Pr co-doped AlN, it disappeared. At the same time, a new peak at 494 nm was observed,although it was not observed for Er-doped AlN or Pr-doped AlN before. Therefore, the energy transfer mechanism between Er~(3+)and Pr~(3+)in AlN thin films was investigated in detail. Through optimizing the dose ratio of Er~(3+)with respect to Pr~(3+), white light emission with an International Commission on Illumination chromaticity coordinate(0.332, 0.332) was obtained. This work may provide a new strategy for realizing white light emission based on nitride semiconductors.     

Synthesis and characterization of ZnO nano/microfibers thin films by catalyst free solution route

Zinc oxide (ZnO) nano/microfibrous thin films were successfully synthesized by a catalyst free solution route on glass and Si substrates. X-ray diffraction study revealed the formation of ZnO nanofibers of hexagonal crystalline structure. The texture coefficient of different planes varied with annealing temperature and that of the (0 0 2) plane was the highest for films annealed at temperature 873 K. Scanning electron micrograph showed the well formation of ZnO nano/microfibers with an average diameter 500 nm and having an average aspect ratio 150. UV–Vis–NIR spectroscopic study for the films deposited on glass substrates showed the high transmittance in the visible and near-infrared region. It was also observed that the band gap energy decreased as the films were annealed at higher temperature. The band gap energies of nanostructured ZnO thin films were determined to be in the range 3.03–3.61 eV. The photoluminescence study showed an UV emission peak at 397 nm, a visible blue–green emission peak at 468 nm and a green emission peak at 495 nm. Field emission properties of nanofiber ZnO thin film showed considerably low turn-on field around 1.4 V/μm. The emission current was as high as 70 μA at the field of 3.6 V/μm.     

水热法制备YVO_4:Eu~(3+)的热处理及其发光性能

用水热法制备的YVO4:Eu3+分别在400～800℃下进行热处理,研究了所得样品的结构及其发光性能。实验结果表明:所得样品都为单相结构,随着热处理温度的升高,样品的结晶度变好,颗粒变大。在紫外光谱范围,YVO4:Eu3+的激发光谱由VO43-的吸收带和Eu3+的电荷迁移带组成。在真空紫外(VUV),激发光谱由基质吸收,Y3+、O2-的电荷迁移带组成。发射光谱均为Eu3+的5D0→7FJ(J=1,2,4)跃迁。紫外和真空紫外激发下,样品的发光强度比未经过热处理的样品有显著增强,归因于样品的结晶度的提高和OH-、VO43-等发光猝灭离子的去除。     

Single violet luminescence emitted from ZnO films obtained by oxidation of Zn film on quartz glass

The photoluminescence (PL) emission properties of ZnO films obtained on quartz glass substrate by the oxidation of Zn films were studied. The strong single violet emission centering about 413-424 nm was observed in the room temperature PL spectra of the ZnO films. The intensity of violet emission increased and the peak position shift from 424 to 413 nm with increasing oxygen pressures. The violet emission was attributed to the electron transition from the valence band to interstitial zinc (Zn_i) level under low oxygen pressure conditions (50-500 Pa). Under high oxygen pressure conditions (5000-23,000 Pa), both interstitial zinc (Zn_i) and zinc Vacancy (V_Zn) were thought to be responsible for the violet emission.     

Synthesis of hexagonal monocrystal AlN microtubes and nanowires at low temperature

This paper reports that pure hexagonal aluminium nitride microtubes and nanowires growing along the [0001] direction have been successfully synthesized by directly reacting AlClh-AlN, microtubes, nanowires,h-AlN, microtubes, nanowiresProject supported by the National Natural Science Foundation of China (Grant No 10474078) and the Science Foundation of the Education Office of Shanxi Province, China.2006-11-23This paper reports that pure hexagonal aluminium nitride microtubes and nanowires growing along the [0001] direction have been successfully synthesized by directly reacting AlCl3 with NaN3 at low temperature （450℃） under condition of non-solvent system. The grey-white powder of reacting product was characterized by high-resolution transmission electron microscope （HRTEM）, which shows that the powder is long straight-wire morphology with outer diameter from 40nm to 300 nm and length up to several micrometres. The results of both electron diffraction （ED） and x-ray diffraction （XRD） indicate that the AlN microtubes have a pure hexagonal monocrystal tubular structure with the combination of the curled AlN nanobelts. Room-temperature photoluminescence spectrum of the synthesized sample showed an emission peak, which is closely related to the small size of the microtubes.     

微波法合成红色长余辉发光材料Gd2O2S:Eu,Mg,Ti及其发光特性

用微波辐射法首次合成了Gd2O2S:Eu,Mg,Ti红色磷光化合物,用X射线粉末衍射(XRD)、扫描电镜(SEM)、荧光分光光度计等对合成产物进行了分析和表征.结果表明:材料的晶体结构为六方晶系,与Gd2O2S的相同.颗粒的形貌为类球形,分散性较好,尺寸在1～2 μm之间.Gd2O2S:Eu,Mg,Ti的激发光谱呈带状,激发光谱主峰位于360 nm,另外在400,422,472 nm等处也有激发峰存在;发射光谱为线状光谱,归属于Eu3 的5DJ(J=0,1,2)到7FJ(J=O,1,2,3,4)的跃迁.随着Eu浓度的增加,位于蓝绿区的586,557,541,513,498,471,468 nm处的发射峰逐渐减弱,而主峰位于627 nm处的红光发射明显增强.当Eu浓度为6 mol%时,红光发射最强.Mg,Ti共掺杂可显著改善其余辉性质.