纳米晶LaAlO3掺Eu3+的复合沉淀法制备及发光性质

以NH₃·H₂O-NH₄HCO₃混合溶液为复合沉淀剂,制备了LaAlO₃:Eu³⁺纳米晶体.通过X射线衍射、扫描电镜和透射电镜对产物进行了表征,用荧光光度计测试了样品的三维荧光光谱、激发光谱和发射光谱.结果表明:前驱沉淀物经800℃焙烧处理2h,制备出球型形貌,颗粒分散性好、尺寸约为40nm的立方相LaAlO₃纳米晶.由三维荧光光谱确定了LaAlO₃:Eu³⁺的最佳监测波长和激发波长,在395nm波长光的激发下观察到纳米LaAlO₃中Eu³⁺的591nm(⁵D₀-⁷F₁)和613nm(⁵D₀-⁷F₂)特征发射谱,磁偶极跃迁⁵D₀-⁷F₁的发射峰强度要比电偶极跃迁⁵D₀-⁷F₂更强,而且这种趋势随着焙烧温度的升高明显增强,说明由该法制备的纳米LaAlO₃中Eu³⁺离子占据的位置具有高的对称性.     

Eu2+掺杂KCaCl3晶体的生长及发光性能

通过坩埚下降法生长出不同物质的量分数Eu²⁺掺杂的KCa_1-xEu_xCl₃(x=0.005、0.01、0.02、0.03、0.05)单晶,并对晶体进行了X射线粉末衍射、热重、透过率、光致发光光谱、衰减时间、X射线激发发射光谱等测定。通过相图及结构分析,判断出该晶体为一致熔融化合物,并得出其为正交结构,晶胞参数为a=0.75604 nm,b=1.04823 nm,c=0.72657 nm,空间群为Pnma(62)。在紫外光的激发下,晶体在434 nm左右有一个宽的发射峰,对应于Eu²⁺的4f⁶5d¹→4f⁷跃迁;光致衰减时间1.473μs,晶体在X射线激发下的发光强度随Eu²⁺离子浓度增加而增强。     

1,4-双(4′-N,N-二甲基氨基苯乙烯基)萘的合成及荧光性质

利用Wittig反应合成了一个以萘为π-Center的对称型“D-π-D”有机绿色发光化合物1,4 双(4′-N,N-二甲基氨基苯乙烯基)萘(BDASN),并测试了其在不同环境中的光谱性质.在378nm激发波长的激发下,BDASN显示出很强的荧光发射峰,峰位在521nm(CH₂Cl₂).随着溶剂极性增大,最大发射波长红移且荧光强度降低,与“D-π-A”分子具有相似的分子内电荷转移(TICT)行为.在β-环糊精(β-CD)中BDASN的绿色发光带被猝灭,同时在450nm附近蓝发光带的荧光强度骤增.     

Cr,In共掺杂MgGa2O4小尺寸近红外长余辉纳米颗粒的制备及发光性能

采用乙二醇辅助共沉淀法制备了小尺寸Cr,In共掺杂MgGa₂O₄(MGO∶Cr, In)近红外长余辉发光纳米粒子(Persistent luminescence nanoparticles, PLNPs), 并考察了Cr, In共掺杂及煅烧温度对MGO晶体结构、 余辉发光性质和尺寸的影响. 结果表明, 最优Cr, In共掺杂浓度分别为0.3%和0.02%, MGO∶Cr, In晶体属于Fd3m空间群, Cr, In共掺杂对纳米颗粒的结构无影响, 平均粒径为(8.61±2.23) nm, 分散性良好, 最佳煅烧温度为700 ℃. 并且, In掺杂可有效延长其余辉发光寿命, 平均发光寿命(τ_av)从49.33 s增大至52.89 s; 荧光量子产率增高至44.9%; 活化能E_a为(0.36±0.04) eV, 具有良好的热稳定性; 陷阱深度为0.696 eV. 此外, 该PLNPs分别在260 nm、410 nm和600 nm处有激发峰, 表明UV光、 蓝绿光以及红光皆可实现对其的激发, 发射波长皆位于705 nm处, 属于Cr³⁺的²E(²G)→⁴A₂(⁴F)跃迁. 该PLNPs在红色LED灯、 光学储器件以及生物医学等领域具有巨大潜在应用价值.     

新型Ce3+掺杂亚磷酸锰开放骨架材料的合成与荧光性质

通过高通量实验方法制备了一系列新型的Ce³⁺离子掺杂亚磷酸锰(NH₄)₄[Mn_4-xCe_x(HPO₃)₆](简称JIS-10∶xCe³⁺) 无机开放骨架材料. 通过粉末X射线衍射(PXRD)谱图、 扫描电子显微镜(SEM)、 微量元素能谱(EDS)、 X射线光电子能谱(XPS)、 傅里叶变换红外(FTIR)光谱和光致发光(PL)光谱等手段对该材料进行了表征, 并研究了Ce³⁺离子掺杂浓度、 反应温度和时间对晶体相变和发光性能的影响. 结果表明, 在波长260 nm的光激发下, Ce³⁺离子在500 nm处有1个绿光发射带而Mn²⁺离子在590 nm处有1个黄光发射带. 调变JIS-10∶xCe³⁺材料中Ce³⁺离子的掺杂浓度发现, 当x=0.06^{时, 即Ce3+离子的掺杂浓度较低时, 样品的发射颜色为黄绿色, 其CIE坐标为(0.38, 0.48); 当Ce3+离子的掺杂浓度增加时, 绿色发光带的增长快于黄色发光带的增长, 从而调整发射颜色; 在x=1.33时观察到最强的发射, 浓度过高发生浓度猝灭.}     

单分散ZnS纳米球与纳米梭之间的形貌转换及光学性能研究

利用平平加作为表面活性剂, 正戊醇作为助表面活性剂, 环己烷作为油相, 以硫化钠(Na₂S)和醋酸锌(Zn(Ac)₂)作为反应物, 通过控制反应条件在反相胶束体系中合成出单分散的ZnS纳米球与纳米梭. 采用XRD和TEM对产物的结构和形貌进行表征, 结果表明产物均为六方相ZnS, 晶胞参数为a＝0.3823 nm, c＝56.2 nm, 纳米球直径约为50 nm, 纳米梭直径约为60 nm, 长度约为110 nm. 采用UV-Vis(紫外可见吸收光谱)和PL(荧光光谱)研究了产物的光学性能. 纳米球的紫外可见光谱的吸收峰出现在288 nm处, 而纳米梭在305 nm处有强吸收峰, 与块体材料相比, 分别有约60和50 nm的蓝移. 当激发波长为270 nm时, 纳米球和纳米梭产物分别能够发出波长为408和303 nm的紫外光.     

过氧化氢激活型近红外氟硼二吡咯光敏剂的设计、合成及光动力治疗研究

基于传统的氟硼二吡咯(BODIPY)荧光染料,设计合成了一种过氧化氢(H₂O₂)激活型近红外光敏剂中位-N-(4-硼酸苄基)吡啶鎓盐取代的碘化双苯乙烯基氟硼二吡咯(FP-IBDP). FP-IBDP在乙腈中的吸收和发射波长均达到近红外区,最大吸收和发射波长分别为681 nm和740 nm,对应的荧光量子效率和单线态氧效率分别为0.01和0.09.在被H₂O₂激活后, FP-IBDP转变为IBDP,其在乙腈中的最大吸收和发射波长分别为661 nm和701 nm.与FP-IBDP相比, IBDP的荧光量子效率和单线态氧效率大幅提升,分别达到0.11和0.48.细胞水平的荧光影像实验表明FP-IBDP对癌细胞内的H₂O₂具有灵敏的响应,并能通过明显的荧光增强变化实现癌细胞与正常细胞的有效区分.活性氧检测实验证明FP-IBDP能够被癌细胞内过表达的H₂O₂激活,并能在660nm光照射下在癌细胞内产生单线态氧.噻唑蓝(MT...     

ZnO纳米棒薄膜的湿化学法制备及光致发光特性

在80 ℃水浴下, 采用简易的湿化学法在不导电玻璃基底上制备了ZnO纳米棒阵列, 利用X射线衍射仪(XRD)和场发射扫描电镜(FE-SEM)对样品的结构形貌进行了表征. 结果表明, 晶化30 min所得产物为六方纤锌矿相的ZnO纳米棒, 直径大约为80~90 nm. 为了分析不同的低温退火温度和退火气氛对其光致发光性能的影响, 研究了ZnO纳米棒薄膜在不同的后处理条件下的光致发光谱(PL). 实验结果表明, 在O₂气氛下于450 ℃退火1 h后, ZnO纳米棒薄膜的红光发射(约650 nm)强度相对在空气和5%H₂/95%N₂气氛下退火的样品变得更强, 而且该样品的激发波长范围(200~370 nm)与近紫外发光二极管(LEDs)的发射波长范围(350~420 nm)匹配得很好.     

ZnS∶Cu纳米微粒的光致发光特性

采用水热法合成ZnS∶Cu纳米粉体，研究了Cu物质的量分数在0～2%范围变化时对ZnS纳米粉体光致发光特性的影响。室温下，用310 nm的波长的光激发发光体，在荧光发射图谱(PLE)中同时观察到了5个发射峰，其中398、423、445～458 nm处的发光属于蓝色发光光谱的分裂，488、530 nm处则为绿色发光光谱的分裂，微量杂质铜的掺入在ZnS晶体中产生新的能级是导致光谱分裂的主要原因。初步探讨了不同发射波长的发射机理。通过X射线衍射(XRD)和透射电子显微镜(TEM)对样品的相结构和形貌进行了表征，结果表明，产物均为立方相结构，粒径大小约为10 nm。紫外可见吸收(UV-Vis)光谱中，吸收峰出现在320 nm附近，由于量子尺寸效应出现了明显的蓝移现象。     

Gd2ZnTiO6∶Dy3+, Eu3+单基质白光荧光粉的制备与发光性能

采用溶胶-凝胶法制备出Dy³⁺, Eu³⁺共掺杂Gd₂ZnTiO₆白光荧光粉. 通过X射线衍射(XRD)、 扫描电子显微镜(SEM)、 光致发光(PL)光谱对荧光粉的物相、 形貌及荧光性质进行了表征. 结果表明, 所制备的样品均为双钙钛矿结构, 属于单斜晶系(空间群: P2₁/n), 形貌为2~5 μm无规则形状的颗粒. 在392 nm近紫外光的激发下, Gd₂ZnTiO₆∶Dy³⁺,Eu³⁺荧光粉展现出Dy³⁺的蓝光、 黄光发射以及Eu³⁺的特征红光发射. 此外, 通过调节Dy³⁺和Eu³⁺的掺杂浓度, 可实现低色温的暖白光发射. 基于样品优异的荧光性能, 该荧光粉在近紫外激发白光LED中具有一定的开发潜力.     

Comparison of optical properties and crystal structures of the praseodymium and europium chloroderivatives of acetates

The praseodymium and europium dichloroacetates were obtained in the form of monocrystals. Crystal structures of the Ln(HCl₂CCOO)₃·2H₂O (Ln=Pr, Eu) compounds were determined by X-ray analysis. Both crystals proved to be isomorphous. They are monoclinic, space group P2₁/n with: a=9.747(6), b=13.857(7), and c=23.595(9) Å, β=95.03(4)°, U=3175(3) Å³, Z=8 for C₆H₇Cl₆O₈Pr and a=9.634(7), b=13.757(11), and c=23.524(14) Å, β=94.84(4)°, U=3107(4) Å³, Z=8 for C₆H₇Cl₆O₈Eu. There are two symmetry independent lanthanide cations, which adopt a nine-coordinate geometry with seven oxygen atoms from carboxylate groups and two oxygen atoms from water molecules. Absorption (Pr³⁺, Eu³⁺), emission and emission excitation (Eu³⁺) spectra of single crystals of Ln(HCl₂CCOO)₃·2H₂O were recorded at room temperature and low temperatures down to 4.2 K. Spectral intensities of the investigated systems are parametrized in terms of the Judd–Ofelt theory and compared to those of lanthanide trichloroacetates and acetates crystals. The relationship between the hypersensitivity and covalency is discussed. The nephelauxetic ratio β and Sinha's parameter δ are calculated based on the absorption spectra. The variation of these parameters and their correlation with the nature of metal–ligand bond is discussed. The bond polarity and bond strength of coordination complex determine the activity and stereospecifity of the catalyst thus the study of these properties are very important because of the application of lanthanide carboxylates as precursors of catalysts. The spectroscopic results are correlated with those from the crystal structure studies, especially with Ln–O distances and the co-ordinating forms of the carboxylate ions. The vibronic coupling in the f–f transitions were analysed. In order to determine the vibronic coupling quantitatively, calculations of the R=I_VIB./I_0-phonon rates were performed from the low temperature absorption spectra. The correlation between the vibronic coupling and covalency is analysed.     

LD激发的ZnWO4:Er3+晶体上转换发光

采用Czochralski法生长出ZnWO₄:Er³⁺(Er=0.02mol)单晶,测量了吸收光谱和激发光谱。在波长966nm功率500mW的激光二极管(LD)激发下观察到上转换发光。强度最大的发射峰位于547和558nm,发射光谱分析表明,上转换激发过程与双光子步进吸收有关。     

Luminescent properties of carbon-rich starburst gold(I) acetylide complexes. Crystal structure of [TEE][Au(PCy3)]4 ([TEE]H4=tetraethynylethene)

Two carbon-rich starburst gold(I) acetylide complexes [TEE][Au(PCy₃)]₄ (3, [TEE]H₄=tetraethynylethene) and [TEB][Au(PCy₃)]₃ (6, [TEB]H₃=1,3,5-triethynylbenzene) were prepared and their UV–vis absorption, emission and excitation spectra have been recorded. In fluid CH₂Cl₂ solutions, 3 exhibits prompt ¹(ππ*) fluorescence with λ_0–0 and λ_max at 413 and 428 nm, respectively, while 6 displays ³(ππ*) phosphorescence with λ_0–0 and λ_max at 446 and 479 nm, respectively. The crystal structure of 3·CH₂Cl₂ has been determined.     

新型(4-HBA)SbX5·H2O类钙钛矿单晶及其卤素结构对发光特性的调控(英文)

发光材料因其在照明、显示、成像等方面的广泛应用而备受关注。作为新兴发光材料之一,钙钛矿类材料的研究及报道较多。其中,铅基钙钛矿的研究取得了巨大进展,光致发光量子产率(PLQY)几乎达到了100%。然而,基于铅基钙钛矿化学毒性和低稳定性,在实际应用过程中需要特殊的封装,因而提高了生产成本并限制了其实际应用领域。被广泛关注的锡基钙钛矿的荧光量子产率几乎能达到90%,但Sn²⁺易氧化成Sn⁴⁺,在空气中极不稳定。相较于铅基钙钛矿和锡基钙钛矿,锑基钙钛矿的低化学毒性、高热稳定性等优点突出。此外,锑基钙钛矿的光学性能在过去几年中也取得了很大的进展,有望突破传统钙钛矿应用的局限。在此,我们报道了一系列新型单晶(4-HBA)SbX₅·H₂O (4-HBA为4-羟基苄胺缩写,X为Cl或Br)。利用溶剂热法可制备高质量的(4-HBA)SbBr₅·H₂O、(4-HBA)SbBr₃Cl₂·H₂O和(4-HBA)S...     

The crystal structure of (η-C6Me6)Ti[(μ-Cl)2(AlClEt)]2 and the catalytic activity of the (C6Me6)TiAl2Cl8−xEtx(x = 0---4) complexes towards butadiene

The composition of (C₆Me₆)TiAl₂Cl_8−xEt_x complexes in (C₆Me₆)TiAl₂Cl₈ + n Et₃Al (n = 0.5-6) systems was studied by UV-Vis spectroscopy and the X-ray crystal structure of one of them, (η⁶-C₆Me₆)Ti[(μ-Cl)₂(AlClEt)]₂ (IIa-2), has been determined. The complex crystallizes in the orthorhombic space group Pna2₁ with Z = 4 and lattice parameters a 15.634(3), b 11.355(2), c 14.417(2) Å. The ethyl groups of IIa-2 reside in outer positions of aluminate ligands farther away from the C₆Me₆ ligand. The other part of the complex does not differ remarkably from structures of other (arene)Ti^II complexes. Negligible activity of (C₆Me₆)TiAl₂Cl₈ towards the butadiene cyclotrimerization is considerably increased by addition of 2.5–3.0 equivalents of Et₃Al. As follows from UV-Vis spectra, such systems contain mainly the (C₆Me₆)TiAl₂Cl₅Et₃ complex. It is suggested that the introduction of three Et substituents destabilizes the Ti-(η⁶-C₆Me₆) bond so that the replacement of hexamethylbenzene by butadiene in the first step of a catalytic cycle becomes more feasible.     

改性SiO2载体对邻菲咯啉钌荧光特性及氧敏感荧光膜性能的影响

为提高极性荧光指示剂Ru(dpp)₃Cl₂在非极性硅橡胶中的分散性,以沉淀白炭黑、气相白炭黑和甲基MQ树脂,载负荧光指示剂Ru(dpp)₃Cl₂,再填充到二甲基硅橡胶(PDMS)中,制备氧敏感荧光膜.以分光光度计和荧光光谱仪,研究载体种类对Ru(dpp)₃Cl₂的吸附性、荧光特性及氧敏感荧光膜性能的影响.白炭黑载负Ru(dpp)₃Cl₂的荧光发射光谱相对其稀溶液约红移20 nm.载体表面的甲基可减弱SiO₂载体对Ru(dpp)₃Cl₂分子的吸附性和相互作用,减少荧光发射光谱的红移12 nm,提高荧光强度近10倍.白炭黑有助改善Ru(dpp)₃Cl₂在PDMS中的分散性和氧敏感荧光膜的荧光输出和猝灭比,尤以MQ树脂的效果最为显著.     

Electrospinning Synthesis and Photoluminescence Properties of SnO2：xEu3＋ Nanofibers

NnO2：xEu3＋（x=O, 1%, 3%, 5%, molar fraction） fibers were synthesized by electrospinning technology. The size of the as-prepared fibers is relatively uniform and the average diameter is about 200 nm with a large draw ratio. The as-prepared Eu3＋ doped SnO2 nanofibers have a rutile structure and consist of crystallitc grains with an average size of about 10 nm. A slight red shift of the A1gand Bag vibration modes and an additional peak at 288 nm were observed in the Raman spectra of the nanofibers. The energies of bandgaps of the SnO2 nanofiber with Eu doping of 1% and 3% are 2.64 eV, and the energy of bandgap is 2.94 eV with Eu doping of 5%（molar fraction）. There is only orange emission（5D0→7F1 magnetic dipole transition） for Eu doped SnO2 nanofibers, and no red emission could be observed. The orange emission upon indirect excitation splits into three peaks and the peak intensity at the excitation wavelength of 275 nm is higher than that at the excitation wavelength of 488 nm.     

一种联咔唑类双极性蓝色磷光主体材料的合成及性能

以联咔唑作为电子给体,二苯基磷氧基团作为电子受体,设计合成了双极性蓝色磷光主体材料6,6'-二(二苯基磷氧基)-9,9'-二己基-3,3'-联咔唑(DPDBC)。通过紫外-可见(UV-Vis)、荧光、低温磷光、循环伏安法、热重分析(TGA)、差热分析(DSC)和密度泛函理论(DFT)对其性能及轨道能级等进行了研究。结果表明,化合物DPDBC在CH₂Cl₂稀溶液中有两个吸收峰,最大吸收峰位于306 nm;它的荧光发射峰位于420 nm,属于深蓝色荧光;DPDBC的低温磷光光谱的第一发射峰位于447 nm,其三重态能级为2.77 eV,与蓝色磷光客体材料FIrpic (2.62 eV)的能级相匹配;测定其循环伏安特性曲线,计算得到它的HOMO能级为-5.48 eV,与阳极ITO的功函(-4.5~-5.0 eV)相匹配,LUMO能级为-2.36 eV,接近于电子传输材料PBD(-2.82 eV),表明它具有双极性能;TGA显示其分解温度为410℃,表明热稳定性能优良,DSC显示其T_g温度为140℃,表明其具有无定形态结构及良好的成膜性能。因此,DPDBC是一种集双极性传输性能于一体,同时又具有优良热稳定性能的潜在蓝色磷光主体材料。     

Atomic and molecular absorption spectra of indium in air-acetylene flame

Absorption spectra of both atomic and molecular species in the air-acetylene flame, which are produced when the aqueous solutions of indium dissolved in HNO₃, HF, HCl, HBr and HI were aspirated into the flame, have been investigated in the u.v. region. Numerous atomic absorption lines of indium have been observed in the absorption spectra. Most of these lines were previously listed only as emission lines. Those atomic lines have been ascribed to the electronic transitions from the ground states of 5p ²P_1/2⁰ and 5p ²P_3/2⁰ to the excited states such as ls ²S_1/2, md ²D_3/2, nd ²D_5/2, 4p^{2 4}P_1/2, 4p^{2 4}P_3/2 and 4p^{2 4}P_5/2, respectively, where 13 l 6 and 14 m,n 5. The molecular absorption bands for InF, InCl and InBr in the airacetylene flame have been also observed near 234 nm, 267 nm and 282 nm, respectively, as the electronic transition of ¹Σ⁺ → ¹Π₁ Those absorption bands show fine structures due to the molecular vibrations. The spectral parameters for the molecular vibrations have been obtained from the simulations of the observed spectra. The molecular absorption band for InI was not observed because of the decomposition of the molecule in the flame. In addition, the molecular absorption band for InO has been observed near 273 nm and those for NO near 205 and 215 nm.