单取代聚乙炔的荧光光谱在低温下的裂变

在18至300 K的温度范围内,对聚乙炔的一种单取代衍生物的荧光特性进行了研究.在室温时,这种聚乙炔的单取代衍生物的薄膜能够发出强的绿色荧光,其荧光光谱的主要荧光峰位于510 nm,而它的两个次要荧光峰分别位于440 nm和380 nm.位于510、440 nm的两个荧光峰分别是该高分子材料所形成的激发缔合物的主要和次要发光峰,而位于380 nm的荧光峰是单条高分子链的发光峰.当温度从300 K降到18 K的过程中,原荧光光谱发生中的激发缔合物的主要发光峰从510 nm逐渐红移到570 nm,而其激发缔合物的次要发光峰逐渐消失;与此同时,该高分子材料的380 nm的荧光峰逐渐与主荧光峰分开.这些光谱方面的变化可用该高分子在低温下所发生的结构上的变化来解释.     

带有咔唑支链的聚乙炔的发光特性研究

在室温下,对单取代聚乙炔(PACz-1)和两种双取代聚乙炔[PACz-2(m=3)、PACz-2(m=9)]的荧光特性和电子结构进行了研究.每种聚乙炔的支链上有一个咔唑单元.虽然它们的分子结构不同,但它们的稀溶液却有相同的吸收峰和强的绿色荧光发射峰,并且它们的吸收谱和发射谱很相似.当溶液的浓度增大到～1×10~(-3)M时,发现有强的绿色荧光发射,峰位位于475 nm.运用Huckel扩展紧束缚计算方法,从理论上计算了带咔唑支链的聚乙炔的电子结构。结果表明单取代聚乙炔和两种双取代聚乙炔的吸收峰、低浓度下的360 nm紫外光发射峰与高浓度下的475 nm的绿色荧光峰都是由于聚乙炔支链上咔唑生色团引起的.     

含铝的富硅二氧化硅薄膜的发光特性及结构

采用双离子束共溅射技术制备出掺铝的富硅二氧化硅复合薄膜(A1SiO)，采用荧光分光光度计对样品进行PL测试表明：A1SiO复合膜共有三个发光峰，分别在370nm、410nm、510nm处。发光峰的位置随铝含量的变化基本上没有改变，峰强随铝含量有变化，且510nm处的峰强随铝含量增加而增强。PLE结果表明：370nm和410nm的PL峰与样品中的氧空位缺陷有关，而510nm的PL峰则是由于铝的掺入改变了样品中的缺陷状态所致，是Al、Si、O共同而复杂的作用。     

动脉粥样硬化斑块和血管壁的光谱学实验研究

为区分动脉粥样硬化斑块和血管壁,给激光血管成形术的实时监控提供依据,研究了动脉粥样硬化斑块和血管壁的激光诱导荧光光谱(LIFS)和拉曼光谱.日本雄性大耳白兔15只,以高脂饲料喂养3个月,取主动脉弓作纵行切开,分别采用380 nm紫外激光和532 nm绿激光作为激发光源诱导动脉粥样硬化斑块和血管肇的荧光光谱;采用532 nm绿激光作为激发光源诱导动脉粥样硬化斑块和血管壁的拉曼光谱.结果表明,380 nm紫外激光诱导的动脉粥样硬化斑块和血管壁的荧光光谱在416 nm处均有明显特征峰,但前者的强度显著高于后者;532 nm绿激光诱导的动脉粥样硬化斑块和血管壁的荧光光谱在800 nm处均有明显特征峰,但强度无明显差别;动脉粥样硬化斑块的拉曼光谱在3000 nm和3300 nm处存在明显的波峰和波谷,而血管壁的拉曼光谱曲线较光滑,无明显特征峰.说明380 nm紫外激光诱导的荧光光谱和拉曼光谱均有可能有效区分动脉粥样硬化斑块和血管壁,而532 nm绿激光诱导的荧光光谱不能有效区分动脉粥样硬化斑块和血管壁.     

动脉粥样硬化斑块和血管壁的荧光光谱学实验研究

为区分动脉粥样硬化斑块和血管壁,以给激光血管成形术的实时监控提供依据,我们研究了动脉粥样硬化斑块和血管壁的激光诱导荧光光谱.选用日本雄性大耳白兔15只,以高脂饲料喂养3个月,取主动脉弓作纵行切开,分别采用380nm紫外激光和532nm绿激光作为激发光源诱导动脉粥样硬化斑块和血管壁的荧光光谱.结果显示:380nm紫外激光诱导的动脉粥样硬化斑块和血管壁的荧光光谱在416nm处均有明显特征峰,但前者的强度显著高于后者;532nm绿激光诱导的动脉粥样硬化斑块和血管壁的荧光光谱均在532nm和800nm处有明显特征峰,但强度无明显差别.说明紫外激光诱导的荧光光谱可以有效区分动脉粥样硬化斑块和血管壁,而532nm绿激光诱导的荧光光谱不能有效区分动脉粥样硬化斑块和血管壁.     

室温350~850 nm ZnSe晶体生长及阴极荧光光谱图谱分析

室温下利用阴极荧光光谱技术对ZnSe晶体进行了350~850 nm的无损全光阴极荧光图谱检测,分析了晶体内部缺陷及夹杂情况,室温下测得ZnSe晶体在400~550 nm的阴极荧光光谱,阴极荧光光谱测得462 nm处的ZnSe本征发光峰。缺陷处测得462 nm的本征发光峰和453 nm的缺陷发光峰,结合能谱分析,ZnSe晶体表面缺陷处的Zn：Se比约为6：4。阴极荧光图谱中缺陷处发光峰主要来自Zn夹杂缺陷发光。     

p型掺杂ZnO薄膜的光致发光特性研究

采用磁控溅射技术,以N2作为p型掺杂源,制备p型N掺杂ZnO薄膜,着重研究了不同掺杂量的N掺杂ZnO薄膜的光学特性。结果表明,掺杂ZnO薄膜在360 nm、380 nm处出现主荧光峰,409 nm、440 nm处出现次荧光峰,而且随着N掺杂量的不同,主、次荧光峰 峰位和强度都会发生变化。当O2∶N2的体积流量比为15∶5时,薄膜中N含量最大,荧光谱中发光峰强度最佳,霍尔效应检测薄膜具有明显的p型导电特征。     

ZnS∶Er纳米晶的水热合成及其性能研究

该文以硫代乙酰胺为硫源,采用水热法合成了ZnS∶Er纳米晶。并用X线衍射(XRD)、透射电子显微镜(TEM)、X线光电子能谱仪(XPS)、荧光光谱仪对其物相、形貌、组成及光学性能进行了表征。结果表明,ZnS∶Er纳米晶为立方闪锌矿结构,粒径约为5nm。由XPS图谱可知,ZnS∶Er纳米晶中存在Zn、S、C、O、Er等元素。ZnS∶Er纳米晶荧光光谱中出现了2个主要发射峰,分别位于469nm和583nm处。两发射峰的发光强度随着pH的升高而增强且发光峰的位置存在微弱的蓝移,pH=12时,两发射峰的荧光强度最强;随着Er3+掺杂量的增加,469nm处发射峰的强度先增强后减弱,583nm处发射峰的强度随之减弱。     

荧光光谱技术在晚期糖基化终末产物中的应用

提出了一种把荧光光谱技术应用于检测晚期糖基化终末产物的方法,重点阐述了该荧光光谱检测系统的测量原理,设计了该荧光光谱检测系统.采用氙灯作为激发光源,利用该系统分别对发射波长为440 nm、445 nm、450 nm、455 nm进行激发光谱扫描测试,得出370 nm为最佳激发波长;采用370 nm的单色光作为激发光源,分别对正常人和糖尿病患者的皮肤组织进行荧光光谱检测,通过获得的荧光光谱分析可发现,两者在450 nm附近的荧光光谱存在明显差异.实验结果证明,该荧光光谱测量系统可应用于晚期糖基化终末产物的检测.     

掺氮ZnO薄膜的光致发光特性研究

采用射频磁控溅射技术,通过改变O2:N2比在玻璃衬底上制备不同浓度N掺杂的ZnO薄膜,研究了掺杂薄膜的光致发光(PL)特性.观察到370～380 nm、390～405 nm附近的2个荧光峰.结果表明,随着薄膜中N掺杂量的不同,荧光峰峰位发生了相应的变化,强度也发生了明显的变化.当Ar:O2:N2为15:7:8时,薄膜中N含量最多,分别在374 nm、391 nm处出现了发光峰且发光强度最佳,此时薄膜已明显表现出p型ZnO薄膜的特征.     

纳米ZnO光学性质研究进展

介绍了纳米ZnO常见发光谱的发光机制。在室温光致发光谱(PL)中,一般在380 nm处出现紫外发光,也有报道在357和377 nm处的紫外发光,列举了几种不同的发光解释。对于深能级发光,一般在400～550 nm出现连续的发光带,也有观察到深能级的声子伴线和声子复制现象。在低温光致发光谱的紫外发射中,一般观察到由自由激子发射(FX)、中性施主束缚激子发射(D0X)、施主-受主对跃迁峰(DAP)、中性施主束缚激子对应的双电子卫星峰(TES)以及声子伴线。综述了纳米ZnO的喇曼光谱、透射光谱、电致发光谱(EL)的特征,最后展望了纳米ZnO的光学性能研究前景。     

Effect of growth conditions on zinc oxide nanowire array synthesized on Si (100) without catalyst

A uniformly distributed ZnO nanowire array has been grown on silicon (100) substrates by catalyst-free chemical vapor transport and condensation. The effect of growth conditions including source heating temperature, substrate temperature, and gas flow rate on growth properties of ZnO nanowire arrays are studied. Scanning electron microscopy, X-ray diffraction, and room temperature photoluminescence are employed to study the structural features and optical properties of the samples. The results show a correlation among experimental growth parameters. There is a zone for substrate temperature, by controlling gas flow rate, that uniformly distributed and well aligned ZnO nanowire arrays can be grown. Also, experiments indicate that ZnO nanowire arrays with different diameter along their length have been formed under various growth conditions in the same distance from source material. It is found that supersaturation is a crucial parameter determining the growth behavior of ZnO nanowire arrays. The growth mechanism of ZnO nanowires is discussed. The room temperature photoluminescence spectrums of ZnO nanowire array show two emission bands. One is the exciton emission band (centered at 380 nm) and the other is a broad visible emission band centered at around 490 nm. As the substrate temperature decreases, the intensity of UV emission increases while the intensity of visible emission peak decreases.     

Electrodeposition and Characterization of ZnO Thin Films

Thin films of ZnO were electrodeposited from an aqueous solution of Zn（NO3 ）2 on indium tin oxide（ITO）-covered glass substrate. The analysis of X-ray diffraction（XRD） and scanning electron micrograph （SEM） indicated that the obtained ZnO films had a compact hexagonal wurtzite type structure with preferable （002） growth direction. A sharp near-UV emission peak located at 380 nm and a strong orange-red emission peak located at 593 nm were observed in the photoluminescence, when excited with 325 nm wavelength at room temperature. Then the prepared ZnO films were introduced as anode phosphors into the field emission test. It was found that orange-red cathode-luminescence was observed and the luminescent brightness was enhanced by annealing. When annealing temperature increased about 600 ℃, the photoluminescence with peak of 531 nm and the green cathode-luminescence were observed. The tests showed that the brightness of about 2 × 102 cd/m^2 was obtained at electric field of 2 V/μm for annealed sample. The results revealed that the film could be a good kind of low-voltage drived cathode-luminescence phosphor.     

用脉冲激光沉积方法制备的ZnO薄膜的结构及光致发光特性

在从室温到800℃的温度范围内,用脉冲激光沉积方法在Al₂O₃（0001）衬底上制备了ZnO薄膜。采用X射线衍射仪、原子力显微镜以及荧光光谱仪分别研究了衬底温度对ZnO薄膜表面形貌、结晶质量和光致发光特性的影响。X射线衍射仪和原子力显微镜的结果表明,当衬底温度从室温升高到400℃时,ZnO薄膜的结构及结晶质量逐渐提高,而当衬底温度超过400℃时,其结构和结晶质量变差;在400℃下生长的ZnO薄膜具有最佳的表面形貌和结晶质量。室温光致发光的测量结果表明,400℃下生长的ZnO薄膜的紫外发光强度最强,且发光波长最短（386 nm）。     

脉冲激光沉积法制备氧化锌薄膜

ZnO是一种新型的Ⅱ-Ⅵ族半导体材料,具有优良的晶格、光学和电学性能,其显著的特点是在紫外波段存在受激发射。利用脉冲激光沉积法(PLD)在氧气氛中烧蚀锌靶制备了纳米晶氧化锌薄膜,衬底为石英玻璃,晶粒尺寸约为28-35 nm。X射线衍射(XRD)结果和光致发光(PL)光谱的测量表明,当衬底温度在100-250℃范围内时,所获得的ZnO薄膜具有c轴的择优取向,所有样品的强紫外发射中心均在378-385 nm范围内,深能级发射中心约518-558 nm,衬底温度为200℃时,得到了单一的紫外光发射(没有深能级发光)。这归因于其较高的结晶质量。     

Near-infrared emission from PbS quantum dots in polymer matrix

PbS quantum dots were prepared in the aqueous medium from readily available precursors. The shape of the particles isapproximately spherical, and the average particle size observed from HRTEM image was 7-8 nm. We applied PbS quantumdots and PMMA polymer to fabricate PbS quantum dots-PMMA composites, and investigate the photoluminescence PbSquantum dots in PMMA matrix with different mass ratio. PbS quantum dots in PMMA matrix have broad emission be-tween 900 nm and 1 500 nm and photoluminescence peak at 1 179 nm. Additionally, the photoluminescence intensityincreases with increasing the dopant concentration. PbS quantum dots-PMMA polymer composites can be potentially usedfor polymer optical fiber and electroluminescence (EL) in optical communication.     

C_(60)薄膜荧光非单指数衰减的四能级模型研究

研究了高真空蒸发技术制备的Ｃ６０薄膜在温度自１２７Ｋ至室温范围的时间分辨荧光光谱，在１２７Ｋ时，Ｃ６０薄膜的荧光峰处于７３０ｎｍ且其时间弛豫特性呈单指数衰减行为；当温度上升时，荧光峰红移，其弛豫特性明显偏离单指数行为。采用四能级模型处理Ｃ６０激发态的弛豫行为，得到双指数衰减规律，并用双指数函数对实验结果进行了拟合，结果表明，当温度上升时，单重态至三重态Ｔ１的系间交叉速率明显增大     

Tris（8—Hydroxyquinoline）Aluminum／2—（4—Biphenylyl）—5—（4—Tertbutylphenyl）—1,3,3—O—xadiazole Organic Multiple Quantum Wells for Electroluminescent Devices

Organic multiple quantum wells(OMQWs) consisting of alternating layers of organic materials have been fabricated from tris(8-hdroxyquinoline) aluminum(Alq)and 2-(4-biphenylyl)-5-(4-tertbutylphenyl)-1,3,3-oxadiazole(PBD)by a multisource-type high-vacuum organic molecular deposition.From the small-angle X-ray diffraction patterns of Alq/PBD OMQWs,a periodically layered structure is confirmed through the entire stack.The Alq layer thickness in the OMQWs was varied from 1 nm to 4 nm.From the optical aborption, photoluminescence and electroluminescence measurements,it is found that the exciton energy shifts to higher energy with decreasing Alq layer thickness,The changes of the exciton energy could be interpreted as the confinement effects of exciton in the Alq thin layers.Narrowing of the emission spectrum has also been observed for the electroluminescent devices(ELDs)with the OMQWs structure at room temperature.     

The First Template‐Free Growth of Crystalline Silicon Microtubes

A simple template‐free high‐temperature evaporation method was developed for the growth of crystalline Si microtubes for the first time. As‐grown Si microtubes were characterized using X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and room‐temperature photoluminescence. The lengths of the Si tubes can reach several hundreds of micrometers; some of them have lengths on the order of millimeters. Each tube has a uniform outer diameter along its entire length, and the typical outer diameter is ≈ 2–3 μm. Most of the tubes have a wall thickness of ≈ 400–500 nm, though a considerable number of them exhibit a very thin wall thickness of ≈ 50 nm. Room‐temperature photoluminescence measurement shows the as‐synthesized Si microtubes have two strong emission peaks centered at ≈ 589 nm and ≈ 617 nm and a weak emission peak centered at ≈ 455 nm. A possible mechanism for the formation of these Si tubes is proposed. We believe that the present discovery of the crystalline Si microtubes will promote further experimental studies on their physical properties and smart applications.