三(8-羟基喹啉)铝(Alq3)发光性能的调控

三(8-羟基喹啉)铝(Alq3)是有机电致发光器件的基础材料.本文评述了如何通过分子的化学修饰和聚集态结构的改变来调控其发光光谱,提高发光效率.这将为开发高性能的有机电致发光材料及器件提供参考与依据.     

8—羟基喹啉铝发光特性及老化的研究

８－羟基喹啉铝（Ｓｌｑ３）非晶薄膜发射峰同多晶粉末的发射峰启亮边的波长相同，但是非晶薄膜的发射峰比多晶粉末的发射峰红移了２０ｎｍ左右。二者的吸收光谱基本相同，说明二者的能带宽度基本相同。非晶薄膜的结构与多晶粉末不同，导致二者的导带结构不同，是二者差别的主要原因。通过地不同条件下存入的单层８－羟基喹啉铝电致发光器件的老年发现其老化的原因主要是器件工作电流的热效应引起非晶薄膜的重结晶。另外，在空气气氛     

可聚合8-羟基喹啉衍生物的合成及高分子化

5氯-甲基-8-羟基喹啉与烯丙醇反应,得到5-(烯丙氧)甲基-8-羟基喹啉可聚合单体,进一步与苯乙烯聚合,得到含8羟-基喹啉基团的高分子。将所得的聚合物与铝离子配位得到高分子配合物(最大发射波长为512 nm)。利用红外光谱、紫外光谱、核磁共振和原子力显微镜(AFM)对配体和配合物的结构进行了表征,利用荧光光谱研究了配合物的光致发光性能。     

甲基化对8-羟基喹啉铝成膜性能的改进

利用8-羟基喹啉的5位氯甲基化的方法设计合成了可溶性的5-甲氧基-8-羟基喹啉铝配合物,并用二氧化硅溶胶成功地把该配合物制备成膜。通过红外、核磁等现代分析手段对配合物结构进行了表征,利用微光色度辐射度测量仪和扫描电镜分别对配合物的发光性质和涂层表面形貌进行表征,并对其发光性能进行了初步探讨。结果表明,5-甲氧基-8-羟基喹啉铝的发光峰波长为580nm,涂层透明且稳定。     

连续含铝SiC自由膜的制备与发光特性研究

通过自制喷膜装置对聚铝碳硅烷(PACS)进行脱泡处理、熔融纺膜,并对其进行氧化交联、高温预烧及高温裂解终烧可制得连续含铝SiC自由薄膜.用扫描电镜(SEM)分析薄膜的形貌,通过红外光谱(FT-IR)分析氧化交联后薄膜的结构变化,通过电子探针(EPMA)、拉曼光谱(Raman)、X射线衍射(XRD)与场发射高分辨透射电子显微镜(HRTEM)对薄膜进行成分及微观结构分析,采用光致发光谱(PL)对薄膜的光学带隙和发光特性进行了研究.结果表明,熔融纺膜法与PACS先驱体法相结合可制得均匀、致密的耐高温连续舍铝SiC自由薄膜,室温下表现出了320～440nm宽谱带发光,其发光峰可分别归因于α-SiC和C簇,且随着烧结温度的提高,发光强度增大.     

射频溅射法制取ZnS*Ag发光薄膜

用烧结ZnS·Ag蓝色荧光粉靶在钇铝柘榴石单晶基片上射频溅射制取了ZnS·Ag蓝色发光薄膜。讨论了基片温度及放电气体中H2 S的含量对薄膜发光特性的影响。实验表明 ,基片加热温度应控制在 50 0℃左右 ,放电气体中H2 S含量应控制在 0 2 %左右 ,所制得的薄膜具有和P2 2 B1荧光粉相同的发光光谱。     

MCM-41与8-羟基喹啉铝复合发光材料的制备与性能研究

以十六烷基三甲基溴化铵（CTAB）为模板剂，正硅酸乙酯（TEOS）为硅源，在有机弱碱和室温条件下制备出高度有序的介孔材料MCM-41。以氯仿、乙醇为混合溶剂，将有机发光小分子8-羟基喹啉铝（Alq3）组装进介孔MCM-41中，得到有机-无机复合发光材料。采用XRD、IR、紫外-可见漫反射、N2吸附-脱附、激发发射等测试方法对产物的结构和性能进行了分析，结果表明，组装体保持了有序的介孔结构，并且主客体之间存在较强的相互作用。     

射频溅射法制取ZnS·Ag发光薄膜

用烧结ＺｎＳ·Ａｇ蓝色荧光粉靶在钇铝柘榴石单昌基片上射频溅射制了ＺｎＳ·Ａｇ蓝色发光薄膜。讨论了基片温度及放电气体中Ｈ２Ｓ的含量对薄膜发光特性的影响。实验表明，基片加热温度应控制在５００℃左右，放电气体中Ｈ２Ｓ含量应控制在０．２％左右，所制得的薄膜具有和Ｐ２２－Ｂ１荧光粉相同的发光光谱。     

下转换发光材料对钙钛矿本征性能的影响研究

利用太阳光的近红外和紫外部分实现全光谱响应无疑已成为提高钙钛矿太阳能电池功率转换效率的重要焦点。通过引入光致发光转换层将近红外或紫外光转换为可见光被钙钛矿光活性层利用,已被认为是一种非常有前景的途径。将两种经典的下转换发光材料(红粉和黄粉)引入钙钛矿本征层,采用一步旋涂法制备钙钛矿薄膜。利用缺陷评定高级显微系统、扫描电镜(SEM)、X射线衍射(XRD)、紫外可见吸收及荧光光谱分别探究了下转换发光材料对钙钛矿薄膜表面粗糙度、形貌、结构及光谱性能的影响。结果表明：下转换发光材料能够优化钙钛矿薄膜表面粗糙度、形貌,并未改变钙钛矿结构。紫外可见分光光度计和荧光光谱仪的结果证实了下转换发光材料确实能够拓宽钙钛矿薄膜的光谱响应范围,使整个吸收光谱范围向短波长方向移动,为有效利用全光谱提供了新思路。     

有机电致发光材料8-羟基喹啉类研究进展

综述了近年来8-羟基喹啉类有机电致发光材料的研究进展,重点讲述在8-羟基喹啉的2、5和7位引入不同基团对其发光的影响,总结了在此领域的实验与研究成果,并探讨其未来前景及研究方向。     

Tris(dialkylamino)aluminums: Syntheses, characterization, volatility comparison and atomic layer deposition of alumina thin films

The syntheses and characterization of both tris(diethylamino)aluminum and tris(diisopropylamino)aluminum are presented in this letter. Characterization includes vapor pressure measurements and comparison of the two non-pyrophoric precursors showing them to be viable alternatives to trimethylaluminum. Ultimately, tris(diisopropyl)aluminum was successful in the atomic layer deposition of alumina thin films.     

Electrochemiluminescence of tris(8-hydroxyquinoline-5-sulfonic acid)aluminum(III) in aqueous solution

The electrochemiluminescence (ECL) of tris(8-hydroxyquinoline-5-sulfonic acid)aluminum(III) in aqueous solution is reported. ECL is generated by complexing aluminum ions with the chelating agent 8-hydroxyquinoline-5-sulfonic acid (HQS) to form Al(HQS)3, followed by oxidation in the presence of tri-n-propylamine (TPrA). The ECL intensity peaks a potential corresponding to oxidation of both TPrA and Al(HQS)3, and the ECL emission spectrum (lambda(max) = 499 nm) matches the photoluminescence emission spectrum, indicating that the emission is from a Al(HQS)3* excited state. ECL efficiencies (phi(ecl), photons generated per redox event) of 0.002 using Ru(bpy)3(2+) (phi(ecl) = 1) as relative standard. Conditions for ECL emission were optimized and used to generate a calibration curve that was linear over the 7 x 10(-6)-4 x 10(-4) M (5-281 mg/L (ppm)) range with a theoretical limit of detection of 1 ppm. The ECL of several metal ions other than aluminum with HQS and effects on Al(HQS)3 ECL were also examined.     

Modified spontaneous emission in oligo (p-phenylene vinylene) planar microcavities

This paper reports on the photoluminescence properties of phenylene vinylene oligomers films (OPV) the emission of which was modified by microcavity effect. Films with 4 and 6 vinyl groups (respectively denoted OPV-4 and OPV-6) were investigated. A strong blue luminescence at 470 nm is observed for OPV-4. OPV-6 shows an emission spectrum quite similar to that of poly phenylene vinylene (PPV). Photoluminescence excitation measurements (PLE) give similar behaviors for the two samples and do not show any change in the shape of the spectra. Ageing under UV irradiation (380 nm) of the unencapsulated OPV-4 layers was evidenced by an exponential decrease of the photoluminescence intensity of about 40% after 3 h a continuous illumination. OPV-6 samples, aged on shelf, for weeks does only show a small decrease (15%) of the PL level over more than 7 h under continuous UV irradiation. Microcavity related effects were observed by inserting the films between two mirrors. These are generally a TiO₂/SiO₂ distributed Bragg reflectors (DBR) as bottom mirror and a Ag film as top mirror. However best results were obtained with two dielectric DBR. As expected, a strong enhancement of the emission at the cavity resonance and pronounced angular effects (emission peaking in the direction normal to the surface of the device) were observed. The importance of the position of the emitting material within the microcavity is evidenced with a thin tris(8-hydroxy) quinoline aluminum (Alq) embedded in SiO₂ with various cavity configurations.     

Chemical and electronic properties of Ba/bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) interfaces for organic light-emitting diodes

The chemistry, electronic structure, and electron-injecting characteristics at the interfaces that were formed between bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (BAlq) and barium (Ba) were investigated using ultraviolet photoemission spectroscopy, near-edge X-ray absorption fine structure spectroscopy, X-ray photoemission spectroscopy, and current-voltage-luminance measurements. The device performance of organic light-emitting diodes (OLEDs), which have a glass/ITO/MoO3/2-TNATA/NPB/BAlq/Ba/Au structure, was significantly improved by inserting a Ba coverage (thetaBa) of 0.2 nm between BAlq and the cathode. For thetaBa'S that were thicker than 0.2 nm, however, even though the electron-injecting barrier heights at the Ba-on-BAlq interfaces were all 0.1 eV, the device performance of the OLEDs with Ba at the interface was degraded with increasing thetaBa. This result indicates that the device performance is largely dependent on the interfacial chemical degradation of the BAlq molecule itself, rather than the electron-injecting barrier height that is determined by the width and chemical structure of the interface, and the formation of barium-induced new gap states at the Ba-on-BAlq interface.     

Tris(8-hydroxyquinoline)aluminum (III) (Alq3) nanowires templated from an eggshell membrane

One to 2-µm long, ≤ 400-nm wide amorphous tris(8-hydroxyquinoline)aluminum (III) (Alq3) nanowires (NWs) grown from the 15-min boiled outer shell membrane (OSM) of the hen's egg and from the OSM solution cast film via thermal evaporation with a source temperature of 260 °C and a substrate temperature of 138 °C under 6.7 × 10⁻² Pa gave about 1.4 to 1.7 times more photoluminescence emission than the control Alq3 sample did, which was grown from the plain glass surface. The characteristic bonding energies of C 1s X-ray photoelectron signal at 282 eV, O 1s signal at 529 eV and N 1s signal at 397 eV suggested that the relatively high NW density for the 15-min boiled OSM and the OSM solution cast film, was mainly caused by the formation of the O═C-O-C═O anhydride moiety and the C═N group in the proteinaceous OSM at high temperature of 90 °C to 100 °C. Therefore, we proposed that the 15-min boiled OSM and the OSM solution cast film apparently served as good templates by providing nano-regions of high concentration of the O═C-O-C═O anhydride groups and the C═N groups for nesting the Alq3 gas molecules to form nano-conical Alq3 nuclei for the growth of long and narrow NWs.     

Tunable distributed feedback lasing with a threshold in the nanojoule range in an organic guest-host polymeric waveguide

Tunable distributed feedback lasing was achieved in a guest-host polymeric waveguide using holographic dynamic gratings. Tris(8-quinolinolato)aluminum (Alq) as a host and 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) as a guest emitter were dispersed in poly(N-vinyl carbazole) (PVCz) matrix. Emission of both the TE(0) and the TM(0) modes was measured. Effective energy transfer from PVCz to DCM through Alq assisted in the reduction of the threshold of laser emission. The threshold of 38 nJ/pulse was measured for first-order lasing and that of 53 nJ/pulse for second-order lasing.     

Synthesis and photophysical properties of core-shell Eu(DBM)3phen/TiO2 nanohybrids

The core-shell titania (TiO2) hybrid spheres embedded with tris(dibenzoylmethanato)phenanthroline [Eu-(DBM)3phen] complex clusters were fabricated by a modified St?ber method. Under ultraviolet excitation (355 nm), the hybrid spheres exhibit the characteristic luminescence of the Eu3+ ions. The experimental results indicate that the titanic shell has different influences on the two fluorescent centers of Eu3+ ions. The emission from the centers on the complex surfaces was greatly enhanced when incorporated into titania spheres.     

Improvement of amplified spontaneous emission performance by doping tris(8-hydroxyquinoline) aluminum (Alq3) in dye-doped polymer thin films

A well-known red fluorescent dye 4-(dicy-anomethylene)-2-t-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) was codoped with an electron transport organic molecule tris(8-hydroxyquinoline) aluminum (Alq(3)) in a host matrix of polystyrene (PS), and the amplified spontaneous emission (ASE) was studied by optically pumping. It was found that the ASE performance was significantly improved by the introduction of Alq(3). The Alq(3):DCJTB:PS blending thin films showed a low threshold (2.4 microJ/pulse) and a high net gain coefficient (109.95 cm(-1)) compared with the pure DCJTB:PS system (threshold of 15.2 microJ/pulse and gain of 35.94 cm(-1)). The improvement of the ASE performance was considered to be attributable to the effective F?ster energy transfer from Alq(3) to DCJTB. Our results demonstrate that the Alq(3):DCJTB could be a promising candidate as gain medium for red organic diode lasers.     

White organic light-emitting diodes from three emitter layers

Three-wavelength white organic light-emitting diodes (WOLEDs) were fabricated using two doped layers, which were obtained by separating the recombination zones into three emitter layers. A sky blue emission originated from the 4,4′-bis(2,2′-diphenylethen-1-yl)biphenyl (DPVBi) layer. A green emission originated from a tris(8-quinolinolato)aluminum (III) (Alq₃) host doped with a green fluorescent 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano [6,7,8-ij]-quinolizin-11-one (C545T) dye. An orange emission was obtained from the N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) host doped with a red fluorescent dye, 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB). A white light resulted from the partial excitations of these three emitter layers by controlling the layer thickness and concentration of the fluorescent dyes in each emissive layer simultaneously. The electroluminescent spectrum of the device was not sensitive to the driving voltage of the device. The white light device showed a maximum luminance of approximately 53,000 cd/m². The external quantum and power efficiency at a luminance of approximately 100 cd/m² were 2.62% and 3.04 lm/W, respectively.