Luminescence properties of red-emitting Ca<Subscript>2</Subscript>Al<Subscript>2</Subscript>SiO<Subscript>7</Subscript>:Eu<Superscript>3+</Superscript> nanoparticles prepared by sol-gel method

A series of red-emitting Ca2-xAl2SiO7:xEu3+(x = 1 mol.%-10 mol.%) phosphors were synthesized by the sol-gel method.The effects of annealing temperature and doping concentration on the crystal structure and luminescence properties of Ca2Al2SiO7:Eu3+ phosphors were investigated.X-ray diffraction(XRD) profiles showed that all peaks could be attributed to the tetragonal Ca2Al2SiO7 phase when the sample was annealed at 1000℃.Scanning electron microscopy(SEM) micrographs indicate that the phosphors have an irregularly rounded morphology with particles of about 200 nm.Excitation spectra showed that the strong broad band at around 258 nm and weak sharp lines in 350-490 nm were attributed to the charge transfer band of Eu3+-O2-and f-f transitions within the 4f6 configuration of Eu3+ ions,respectively.Emission spectra implied that the red luminescence could be attributed to the transitions from the 5D0 excited level to the 7FJ(J = 0,1,2,3,4) levels of Eu3+ ions with the main electric dipole transition 5D0→7F2(618 and 620 nm),and Eu3+ ions prefer to occupy a lower symmetry site in the crystal lattice.Moreover,the photoluminescence(PL) intensity was strongly dependent on both the sintering temperature and doping concentration,and the highest PL intensity was observed at an Eu3+ concentration x = 7 mol.% after annealing at 1100℃.The obtained Ca2Al2SiO7:Eu3+ phosphor may have potential application for the red lamp phosphor.     

Template-free hydrothermal synthesis of single-crystalline SnO<Subscript>2</Subscript> nanocauliflowers and their optical properties

Large-scale single-crystalline SnO₂ nanocauliflowers were successfully synthesized using a hydrothermal growth method without any template. The samples were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). FE-SEM images show that the as-grown SnO₂ nanocauliflowers are constructed of tetragonal prisms with a width of 500–600 nm. XRD, EDS, and SAED results indicate that the as-grown SnO₂ nanocauliflowers are single crystalline with the tetragonal rutile crystalline structure. The growth mechanism of SnO₂ nanocauliflowers is also preliminarily discussed on the basis of different Sn(OH)₆²⁻ concentrations, and it is found that Sn(OH)₆²⁻ concentration plays an important role in determining the shape of the prepared SnO₂. Room temperature photoluminescence was further carried out on SnO₂ nanocauliflowers to investigate their optical properties. An intense blue luminescence centered at a wavelength of 424 nm is observed in the as-grown SnO₂ nanocauliflowers.     

蓝光材料FIrpic的合成、结构表征及光物理性能测试

以水合三氯化铱和 dfppy 为原料,在乙二醇单乙醚溶剂中反应得氯桥二聚体(dfppy)2Ir(μ-Cl2)Ir(dfppy)2,然后在碱性条件下与2-吡啶甲酸反应合成出 FIrpic。通过核磁共振谱(1HNMR、13CNMR)、质谱、红外光谱和单晶X射线衍射等确定了分子结构,高效液相色谱法(HPLC)测试了纯度,利用紫外-可见吸收光谱和光致发光光谱对其光物理性能进行了测试。结果表明：FIrpic为电中性八面体配合物,在476 nm处出现了较强的蓝光发射,其合成产率大于90%,纯度为99.22%,该方法适于FIrpic的批量制备。     

电子辐照GaInP/GaAs/Ge三结太阳电池少子寿命的变化

为研究电子辐照空间太阳电池的损伤机制,对电子辐照GaInP/GaAs/Ge三结太阳电池进行了光致发光谱测量,分析了GaInP顶电池及GaAs中间电池发光强度随电子注量的变化规律。利用辐射效率关系对归一化发光强度随电子辐照注量的变化进行了拟合,分别得到了GaInP顶电池及GaAs中间电池在不同辐照条件下的少子非辐射复合寿命τ_nr,通过对比辐照前后少子非辐射复合寿命的衰降变化,发现GaInP顶电池的抗辐照性能优于GaAs中间电池。     

可溶性聚(2-甲氧基-5-辛氧基)对苯乙炔的制备及性能

通过双醚化反应、氯甲基化反应和强碱诱导的脱氯化氢反应,制备出可溶性聚(2-甲氧基-5-辛氧基)对苯乙炔(PMOCOPV)。利用傅里叶变换红外光谱(FT-IR)、核磁共振谱(1H-NMR)、紫外-可见吸收光谱(UV-Vis)和凝胶渗透色谱(GPC)对PMOCOPV的结构进行表征。研究表明,PMOCOPV在三氯甲烷中具有良好的溶解性,利于成膜。热性能研究表明其热稳定性良好,起始分解温度约为200℃。荧光光谱研究表明,PMOCOPV具有优良的光致发光性能,其最大发射波长为641 nm,荧光寿命为7.5×10-10s。     

熔盐电解合成碳化硅纳米颗粒及其光致发光特性（英文）

提出一种一步熔盐电化学方法,以超细二氧化硅和碳粉混合物为原料合成碳化硅纳米颗粒。通过X射线衍射、电子显微镜、拉曼光谱、光致发光光谱等系统研究电解合成过程及产物的物化特性。提出二氧化硅/碳粉在氯化钙熔盐中电解合成纳米碳化硅时存在化学/电化学复合、电化学脱氧和原位碳化的耦合反应机理。结果表明,所制备的碳化硅纳米颗粒的粒径集中分布在8～14 nm,并具有多晶结构。此外,由于协同的尺寸效应和微观结构特征,碳化硅纳米颗粒具有明显的光致发光特性。     

ZnO纳米锥光致发光性及印刷ZnO纳米锥场发射性能研究

利用物理热蒸发法制备大规模的蒲公英状的ZnO纳米锥,利用荧光光谱仪对ZnO纳米锥进行了光致发光性能测试.针对现有的丝网印刷碳纳米管(CNTs)薄膜需要各种后处理工艺后才能改善其场发射特性的问题,提出了一种不需任何后处理丝网印刷ZnO纳米锥的浆料配制工艺.用该工艺制备的丝网印刷ZnO纳米锥的场发射特性测试表明,ZnO纳米锥与制浆剂质量比为3∶5的薄膜的开启场强最低为2.25V/μm(电流密度为1μA/cm2),在4.6V/μm场强下,阳极荧光粉的发光点亮度高且分布均匀.说明该方法成本低,工艺简单,无需任何后处理,在ZnO纳米锥场发射显示器的制作中有很好的实际应用价值.     

氧化锌纳米棒有序阵列的制备及表征

氧化锌是一种重要的化合物半导体,其低维结构在微电子器件领域具有潜在的应用前景.在温和的条件下利用软化学方法在沉积了单层ZnO颗粒膜的玻璃衬底上制备了直径为70～300nm,长约1μm的氧化锌纳米棒有序阵列,讨论了颗粒膜对阵列生长的作用以及水浴温度对晶体结构和形貌的影响.结果表明,产物为纤锌矿结构;ZnO颗粒膜为阵列的生长提供了分布均匀且固定的形核中心,对阵列的有序生长起诱导作用;随着反应温度的升高,阵列直径变小且排列更加有序,但过高的温度会抑制ZnO晶体内部的c轴择优取向作用.研究了ZnO阵列的光致发光特性,初步讨论了其发光机理.     

新型含长链β-二酮环状金属铂配合物的光致发光和电致发光研究

测定了新型含长链β-二酮环状金属铂配合物YDETPt的量子效率、磷光寿命、吸收光谱和发光光谱,并研究了其光致发光和电致发光性能.结果表明,在521nm处有较强的金属配合物三重态磷光发射,是一种绿色磷光材料.配合物在主体材料中掺杂浓度为8%的器件,外量子效率最大,达到0.87%.     

Excitonic Properties of Chemically Synthesized 2D Organic–Inorganic Hybrid Perovskite Nanosheets

2D organic–inorganic hybrid perovskites (OIHPs) represent a unique class of materials with a natural quantum‐well structure and quasi‐2D electronic properties. Here, a versatile direct solution‐based synthesis of mono‐ and few‐layer OIHP nanosheets and a systematic study of their electronic structure as a function of the number of monolayers by photoluminescence and absorption spectroscopy are reported. The monolayers of various OIHPs are found to exhibit high electronic quality as evidenced by high quantum yield and negligible Stokes shift. It is shown that the ground exciton peak blueshifts by ≈40 meV when the layer thickness reduces from bulk to monolayer. It is also shown that the exciton binding energy remains effectively unchanged for (C₆H₅(CH₂)₂NH₃)₂PbI₄ with the number of layers. Similar trends are observed for (C₄H₉NH₃)₂PbI₄ in contrast to the previous report. Further, the photoluminescence lifetime is found to decrease with the number of monolayers, indicating the dominant role of surface trap states in nonradiative recombination of the electron–hole pairs.