Deep‐red light‐emitting phosphorescent dendrimer encapsulated tris‐[2‐benzo[b]thiophen‐2‐yl‐pyridyl] iridium (III) core for light‐emitting device applications

New deep‐red light‐emitting phosphorescent dendrimers with hole‐transporting carbazole dendrons were synthesized by reacting tris(2‐benzo[b]thiophen‐2‐yl‐pyridyl) iridium (III) complex with carbazolyl dendrons by DCC‐catalyzed esterification. The resulting first‐, second‐, and third‐generation dendrimers were found to be highly efficient as solution‐processable emitting materials and for use in host‐free electrophosphorescent light‐emitting diodes. We fabricated a host‐free dendrimer EL device with configuration ITO/PEDOT:PSS (40 nm)/dendrimer (55 nm)/BCP (10 nm)/Alq₃ (40 nm)/LiF (1 nm)/Al (100 nm) and characterized the device performance. The multilayered devices showed luminance of 561 cd/m² at 383.4 mA/cm² (12 V) for 15 , 1302 cd/m² at 321.3 mA/cm² (14 V) for 16 , and 422 cd/m² at 94.4 mA/cm² (18 V) for 17 . The third‐generation dendrimer, 17 (η_ext = 6.12% at 7.5 V), showed the highest external quantum efficiency (EQE) with an increase in the density of the light‐harvesting carbazole dendron. Three dendrimers exhibited considerably pure deep‐red emission with CIE 1931 (Commission International de L'Eclairage) chromaticity coordinates of x = 0.70, y = 0.30. The CIE coordinates remained very stable with the current density. The integration of rigid hole‐transporting dendrons and phosphorescent complexes provides a new route to design highly efficient solution‐processable materials for dendrimer light‐emitting diode (DLED) applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7517–7533, 2008     

基于Mn掺杂ZnS量子点的室温磷光传感应用的研究进展

与一般有机染料分子相比,半导体材料量子点具有优异的光学性能,在多个领域得到了广泛的应用.量子点具有窄而对称且可调的发射波长、宽激发强吸收、抗光漂白能力强以及水溶性好等诸多优势,引起了研究者广泛关注.为了增加量子点的斯托克斯位移从而很好地避免量子点的自猝灭现象,引入掺杂物是一种很有效的方式.掺杂量子点不仅保留了量子点原有的优点,而且还赋予量子点额外的优异性能.如Mn掺杂ZnS量子点生物相容性好,不含Cd和Hg等有害元素,而且Mn2+的加入使其具有优异的室温磷光特性.磷光检测能很好地避开生物背景荧光的干扰,使得Mn掺杂ZnS量子点能够广泛应用于磷光生物分析.本文综述了Mn掺杂ZnS量子点在室温磷光分析中的研究进展,着重介绍了几种具有启发意义的设计策略,包括其发光机理以及应用于离子、分子以及生物大分子等的检测.     

Metal nanoparticle-enhanced room temperature phosphorescence of diiodofluorescein on the filter paper substrate

<正>Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at room temperature,as well as to increase the excitation rate of lumophores at room temperature.     

Pure red electrophosphorescence from polymer light-emitting diodes doped with highly emissive bis-cyclometalated iridium(III) complexes

In order to develop highly emissive red phosphorescent materials for OLED application, novel bis-cyclometalated iridium(III) complexes were developed using the 1-(dibenzo[b,d]furan-4-yl)isoquinolinato-N,C^3′ (dbfiq) cyclometalating ligand. When 1,3-bis(3,4-dibutoxyphenyl)propane-1,3-dionate (bdbp) is employed as an ancillary ligand, Ir(dbfiq)₂(bdbp) 1 exhibits red photoluminescence (PL) at 640 nm with a quantum yield (Φ_PL) of 0.61 (in toluene, 298 K). Replacement of bdbp to dipivaloylmethanate (dpm) and acetylacetonate (acac) (Ir(dbfiq)₂(dpm) 2 and Ir(dbfiq)₂(acac) 3, respectively) does not affect the PL spectrum, but reduces Φ_PL to 0.55 and 0.49 for 2 and 3, respectively. Similar tendency is also found in the doped poly(methyl methacrylate) (PMMA) film, and 1 is more emissive (Φ_PL = 0.17) than 2 and 3 (Φ_PL = 0.08 and 0.06, respectively). Using 1 as a phosphorescent dopant, polymer light-emitting diodes (PLEDs) were fabricated, of which structure was ITO/PEDOT:PSS (40 nm)/PVCz:1:PBD (100 nm)/CsF (1 nm)/Al (250 nm). Pure red electroluminescence (EL) is obtained from the fabricated PLEDs, affording a CIE chromaticity coordinate of (0.68, 0.31). When 0.51 mol% of 1 is incorporated in the PVCz-based emitting layer, the PLED shows maximum luminance of 7270 cd m⁻² at 16.5 V, power efficiency of 1.4 lm W⁻¹ at 7.5 V, and external quantum efficiency of 6.4% at 9.0 V. PLEDs with the same structure and components were also fabricated using 2 and 3, and their device characteristics were investigated. In proportion to the PL quantum yields, 1 affords better device performance than 2 and 3. Owing to four butoxy groups introduced to the bdbp ligand, 1 exhibits high solubility in organic solvents such as chloroform and toluene, and thus, is an excellent red phosphorescent dopant for solution-processed OLEDs.     

Simultaneous Optimization of Luminance and Color Chromaticity of Phosphors Using a Nondominated Sorting Genetic Algorithm

Acquiring materials that simultaneously meet two or more conflicting requirements is very difficult. For instance, a situation wherein the color chromaticity and photoluminescence (PL) intensity of phosphors conflict with one another is a frequent problem. Therefore, identification of a good phosphor that simultaneously exhibits both desirable PL intensity and color chromaticity is a challenge. A high‐throughput synthesis and characterization strategy that was reinforced by a nondominated sorting genetic algorithm (NSGA)‐based optimization process was employed to simultaneously optimize both the PL intensity and color chromaticity of a MgO–ZnO–SrO–CaO–BaO–Al₂O₃–Ga₂O₃–MnO system. NSGA operations, such as Pareto sorting and niche sharing, and the ensuing high‐throughput synthesis and characterization resulted in identification of promising green phosphors, i.e., Mn²⁺‐doped AB₂O₄ (A = alkali earth, B = Al and Ga) spinel solid solutions, for use in either plasma display panels or cold cathode fluorescent lamps.     

Induced phosphorescence of some aza- and thio-stilbenes embedded in thallium-exchanged zeolites

The emission properties of some aza-stilbenes (2-, 3- and 4-styrylpyridine) and thio-stilbenes [2- and 3-styrylthiophene and 1,2-di-(3-thienyl)ethene] have been investigated after inclusion in commercial (NaY) and cation-exchanged (TlY) faujasite zeolites to get information on the triplet properties through population of the T₁ state induced by the heavy atom effect. The fluorescence properties in NaY and TlY were compared with those reported in solution. The phosphorescence spectra, observed in TlY at liquid nitrogen temperature, allowed the energy levels of the T₁ states to be obtained. Phosphorescence lifetimes were also measured. Their comparison with the lifetime known for stilbene showed that the radiative decay is little affected by the heteroatoms.     

非离子表面活性剂Brij35胶束体系中α-溴代萘的室温燐光

建立了非离子表面活性剂Ｂｒｉｊ３５胶束介质中α－溴代萘的燐光分析法，并与十二烷基 硫酸钠ＳＬＳ体系作了比较。方法特点如下：α－溴代萘在低浓度的Ｂｒｉｊ３５胶束溶液中即产生 ＲＴＰ发射，具有良好的分析特性。甲醇、乙醇等的加入，体系不会使燐光达到稳定的时间增长，测量操作简便。ＴｌＮＯ３的存在使背景降低，精密度提高。Ｂｒｉｊ３５体系比 ＳＬＳ体系具有较大 的粘度，较小的丙酮猝灭影响。     

沉淀法合成纳米晶长余辉材料Y2O2S∶Eu3+，Ti

The long-lasting phosphorescent materials, yttrium oxysulfides doped by Eu and Ti, were systhesized by coprecipitation with their subsequent thermal decomposition in the presence of sulphur. The products were characterized by XRD, TEM, phosphorescent spectra, and thermoluminescence. The XRD results indicate that the lowest synthesis temperature is 700 ℃. From the TEM, the average diameter of particles was in the range of 60～120 nm, and augmented with the increase of temperature. The materials under UV excitation presented well afterglow from the transition of ⁵D_0,1 → ⁷F_J of Eu³⁺, and the persistent time was about 2 h. The long-lasting afterglow mechanism was discussed, too.     

Long-lived phosphorescence of aqueous solutions of β-cyclodextrin complexes with naphthalene and its derivatives at room temperature

A long-lived phosphorescence at room temperature (lifetime>1 s) of aqueous solutions of β-cyclodextrin complexes with naphthalene and its derivatives was found. The phosphorescence isobserved for aggregated complexes that form in water a light-scattering suspension, and its low intensity is due to predomination of 2∶2 complexes with efficient excimer fluorescence. Complexes containing isolated aromatic molecules are assumed to be the centers of fluorescence. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2022–2024, October, 1999.     

A novel application of nylon membranes to the luminescent determination of benzo[a]pyrene at ultra trace levels in water samples

Very simple and highly sensitive methods are presented for the determination of benzo[a]pyrene, one of the most carcinogenic polycyclic aromatic hydrocarbons (PAHs). The approaches are based on solid-phase extraction of the analyte on a nylon membrane via a syringe procedure, and its fluorescent or phosphorescent determination on the solid surface. While the native fluorescence of benzo[a]pyrene retained on a nylon surface is measured directly, room-temperature phosphorescence is induced by spotting a few microlitres of thallium(I) nitrate solution on the surface (heavy-atom effect). An enhancement of the phosphorescence signal was corroborated when the measurements were carried under a nitrogen atmosphere. The analytical figures of merit obtained under the best experimental conditions demonstrate the capability of detecting benzo[a]pyrene at a sub-parts-per-trillion (sub-ng L⁻¹) level. The potential interference from other common PAHs and also from different metal ions was studied. The feasibility of determining benzo[a]pyrene in real samples was successfully evaluated through the analysis of spiked tap, underground and mineral water samples of different origins. Recoveries obtained from spiked river waters were successfully compared with those provided by a reference method, through rigorous statistical analysis.