基于三萘苯的溶液可加工螺旋形寡聚物的合成及其在蓝光有机电致发光器件中的应用（英文）

近年来,人们在有机电致发光材料和器件结构方面取得了巨大的进步。然而由于蓝光材料具带隙宽的内禀属性,在发光效率、色纯度和稳定性上仍然面临巨大挑战。本文将螺旋形三萘苯共轭体系引入电致发光材料领域,它独特的螺旋形分子结构和易于化学修饰的特点有利于抑制聚集体和基激缔合物的形成。通过Si Cl4催化的环三缩合反应和Suzuki偶联反应,我们设计合成了以三萘基苯为核心,萘、蒽和三苯胺为取代基团的系列螺旋形蓝光寡聚物,并系统地研究了它们的热学、光物理和电化学性质。研究发现,萘和三苯胺取代的寡聚物1,3,5-三(3-(1-甲氧基萘-2-基)-4-甲氧基萘-1-基)苯(TNNB)和1,3,5-三(3-(4-(N,N-二苯胺基)苯基)-4-甲氧基萘-1-基)苯(TPANB)具有最好的热稳定性。在溶液中,这两种材料都具有深蓝发射,发射峰分别为382和415 nm;在薄膜中,TNNB的发射峰仅有1 nm的红移,而TPANB甚至产生了6 nm的蓝移。以这些寡聚物为发光材料,通过旋涂法制备的有机电致发光器件结果表明,基于TNNB的器件获得了最大亮度达到5273 cd?m(-2)~,色坐标(0.17,0.11)的纯蓝光器件。     

基于三苯胺和螺(芴-9,9'-氧杂蒽)的星射形蓝光寡聚材料的合成与光电性质

通过Sonogashira 反应合成了基于三苯胺、螺(芴-9,9'-氧杂蒽)及芴的星射形寡聚物. 三种寡聚物(TPA-F、TPA-SFX和TPA-SFXCz)都具有很高的热分解温度, 分别为417、439和425 °C. 差示扫描量热(DSC)分析研究表明, 它们也具有高的玻璃化转变温度(T_g), 都在100 °C以上, 其中两种螺芴取代的寡聚物(TPA-SFX和TPA-SFXCz)的T_g分别达到141和127 °C. 光物理的研究发现, 在薄膜中, TPA-F具有很宽的双发射峰, 峰值为424 和455 nm; 而TPA-SFX 和TPA-SFXCz 仍保持单一蓝光发射, 发射峰分别为434 和442 nm. 这表明将三苯胺非平面结构和螺形取代基团相结合, 能有效抑制在薄膜中聚集和激基缔合物的产生. 电化学的研究表明, 由于引入富电子的三苯胺核心结构, 三者都具有-5.4 eV左右的较高的HOMO能级. 通过旋涂法制备了结构为ITO(氧化铟锡)/PEDOT:PSS(聚3,4-乙撑二氧噻吩:聚苯乙烯磺酸盐)/寡聚物/TPBI(1,3,5-三(1-苯基-1H-苯并咪唑-2-基)苯)/LiF/Al 电致发光器件. 器件测试结果表明, TPA-SFX的器件具有最好的光电性能. 以它为发光层, 获得最大亮度为2680 cd·m^-2、最大电流效率为0.35 cd·A^-1、色坐标为(0.17, 0.13)的蓝光器件.     

自主体发光的蓝绿色磷光Ir(Ⅲ)配合物的合成及光电特性

合成了一类自主体蓝绿色磷光铱(Ⅲ)配合物(CzPhBI)₂Ir(tfmptz), (CzPhBI)₂Ir(tfmpptz)和(CzPhBI)₂Ir(fpptz)[其中CzPhBI, tfmptz, tfmpptz和fpptz分别为9-[6-(2-苯基-1-苯并咪唑基)己基]-9-咔唑、 2-(5-三氟甲基-1,2,4-三唑基)吡啶、 2-(5-[4-(三氟甲基)苯基]-1,2,3-三唑)吡啶和2-[5-(4-氟苯基)-1,2,3-三唑]吡啶]. 通过核磁共振氢谱和氟谱及元素分析确定其分子结构, 并对其光物理性能进行了研究. 利用该类配合物作为单发光层制备了器件结构为氧化铟锡(ITO)│N,N'-二苯基-N,N'-二(1-萘基)-1,1'-联苯-4,4'-二胺(NPB)(30 nm)│4,4'-N,N'-二咔唑基联苯(CBP)(15 nm)│Ir配合物(30 nm)│1,3,5-三(1-苯基-1H-苯并咪唑-2-基)苯(TBPI)(30 nm)│LiF(1 nm)│Al(100 nm)的电致发光器件, 其最大亮度为6913 cd/m², 最大发光效率达13.9 cd/A.     

三苯胺类小分子的合成及其AIE性能研究

以二苯胺、碘苯、对碘甲苯以及对碘苯甲醚为原料,合成了三苯胺及其衍生物T1~T5(4-甲氧基三苯胺、4-甲基三苯胺、4-醛基三苯胺、4-乙烯基三苯胺),并对其紫外-可见吸收光谱与荧光光谱进行了检测。结果表明,连有甲氧基、甲基、乙烯基取代基的三苯胺化合物在甲醇/氯仿混合溶液中具有聚集诱导发光(AIE)性能;而醛基取代的4-醛基三苯胺表现出了聚集荧光猝灭(ACQ)现象。     

胺烷基侧链取代三苯胺类红光聚合物的合成及性能研究

通过Suzuki偶合反应合成了一系列胺烷基侧链取代的基于三苯胺和芴的共轭聚合物聚[4-(N,N-二甲基胺丙氧基)苯-4,4′-二苯胺-9,9-二辛基芴-4,7-二噻吩-2-基-2,1,3-苯并噻二唑](PFTD), 并对其化学结构和光电性能进行了表征. 末端胺基的存在提高了此类聚合物作为发光层应用于聚合物电致发光器件的性能(采用高功函数的金属铝作为阴极时). 结构为ITO/PVK/PFTD-5(DBT摩尔分数为5%时的聚合物)/Al的器件最大电致发射峰位于647 nm, 最大外量子效率达到了1.24%.     

窄光谱磷光配合物的设计及电致发光性能

通过对螯合配体及辅助配体的设计与筛选, 构筑了一种全新的天蓝光铱金属配合物(MeFPyPy)₂Ir(dipcMePy)(简称MFPMP), 实现了三重态配体中心、 三重态金属-配体电荷转移和/或三重态配体-配体电荷转移跃迁类型混合比例较优化的发光过程. 以MFPMP作为发光体的磷光有机电致发光器件实现了半峰宽为52 nm, 最大发光波长为476 nm的窄光谱、 单峰型、 高亮度、 高效率天蓝光发射, 并在1000 cd/m²的实用亮度下保持了25%以上的外量子效率(EQE), 与目前报道的最高水平有机电致发光器件性能相当. 本工作为进一步开发色纯度更高、 更具有实用性的磷光配合物发光材料提供了一条可行的途径.     

9,9-二-(3-(9-苯咔唑基))-2,7-芘基芴的光电性质

芴类化合物作为有机电致发光材料近年来引起了人们的广泛关注, 其具有高亮度和高工作效率等性能. 本论文采用量子化学方法研究了一种新型的芴类发光材料, 9,9-二-(3-(9-苯咔唑基))-2,7-芘基芴的光电性质. 具体研究内容包括基态和激发态几何结构、前线分子轨道、能隙、电离能、电子亲和势、重组能以及吸收光谱和发射光谱等. 理论计算结果表明, 9,9-二-(3-(9-苯咔唑基))-2,7-芘基芴发射光谱为450.6 nm, 其在电致发光器件应用上是一种具有开发前景和实用价值的蓝光发光材料.     

新型铱配合物的合成及电致发光性质研究

合成了一种新型橙红色磷光材料铱的配合物(npp)₂Ir(acac)(npp=2-(1-萘基)-4-苯基吡啶，acac=乙酰丙酮)，通过 ¹H NMR、MS、元素分析对其结构进行了表征。以铱配合物(npp)₂Ir(acac)作为发光体，制备了结构为ITO/Ir(5%)：PVK(60 nm)/F-TBB(15 nm)/Alq₃(15 nm)/LiF(1 nm)/Al(150 nm)的电致发光器件，研究了其电致发光性质。结果表明器件的最大发射波长在599 nm，最大发光亮度为3 841 cd·m^-2，最大电流效率达3.9 cd·A^-1。     

二苯胺取代吖啶衍生物发光材料的合成、表征及电致发光性能

设计合成了2个苯胺取代吖啶衍生物N3,N3,N6,N6-四苯基吖啶基-3,6-二胺(1)和N3,N3,N6,N6-四对甲苯基吖啶基-3,6-二胺(2),通过化学修饰在吖啶核的两端引入二苯胺取代基可以调节化合物的能级和堆积结构等性质,从而使这些吖啶衍生物具有良好的发光性能,可用于制备电致发光器件.基于吖啶衍生物为掺杂发光材料制备的电致发光器件均呈现绿光发射,器件开启电压较低(2.4 V),以化合物1和2制备的器件最高功率效率分别为4.9和8.2 lm/W.考察了其光物理、电化学、热学和荧光量子效率等性能.结果表明,化合物1和2具有较高的量子效率及匹配的能级结构,这是获得较高电致发光效率的基础.     

液晶性直线型共轭芳炔衍生物的合成及电致发光性质

以苯胺和芳炔为基本构筑单元,通过Sonogashira偶联反应, 合成了一种新型含氨基的结构不对称π共轭线性芳炔化合物5-{(6-己氧基萘基)丁二炔}-2-{(4-氨基苯基)乙炔}苄醇。 通过化学修饰在芳炔类小分子端基引入氨基取代基,使其在无吸电子基团存在的条件下通过扭转态的形成实现分子内电荷的有效转移,从而提高芳炔类衍生物电-光转换效率。 同时,通过赋予芳炔类小分子液晶性,有效改善电子与空穴在器件中的电荷平衡,提高器件的效率。 基于氨基取代芳炔衍生物为掺杂发光材料制备的电致发光器件呈现黄绿光发射,器件开启电压较低(7.20 V),显示了较好的电致发光稳定性,器件17.65 V时达到最大亮度126 cd/m²,是一种潜在的电致发光材料。     

含六苯基苯结构单元桨型分子的合成及光致发光特性

以1,3,5-三苯基苯为中心核, 4-乙烯基联苯为桥联结构, 通过Heck偶联反应合成了含六苯基苯结构单元的桨型分子, 对其结构进行了表征; 对桨型分子及其结构单元[包括4-乙烯基联苯、含六苯基苯结构的“臂”及其母体结构1,3,5-三(4-苯乙烯基苯基)苯]在溶液中的光致发光特性的研究结果表明, 桨型分子具有2个发光中心, 最大发射波长在蓝色光范围内分别为397和445 nm.     

Synthesis and photophysical properties of hyperbranched polyfluorenes containing 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine as the core

A series of new hyperbranched polymers containing a 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core unit and polyfluorene chain arms have been synthesized via Suzuki coupling, and characterized by NMR, IR and GPC. All the polymers exhibit good thermal stability with a high decomposition temperature. By changing the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio the UV-vis absorption and emission spectra can be partially tuned. It has been found that the polymers containing a low ratio of 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine units (P1-P3) have an absorption maximum around 385 nm, localized in the polyfluorene chain, and a shoulder around 425 nm ascribable to a charge transfer state involving the fluorene and the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine core. Increasing the molar ratio of the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine unit enhances the charge transfer band which becomes dominant for P4. The LUMO level of these polymers is relatively low due to the electron affinity of the triazine group. The polymers show dual emission, with a structured band in the blue (410-440 nm), attributed to the polyfluorene, and a broad band in the red (470-500 nm) associated with the charge transfer state. All the polymers exhibit two-photon absorption activity in the range of 660 to 900 nm with the maximum two-photon absorption (TPA) cross-section red-shifted from the corresponding linear absorption. The values of the TPA cross-sections vary from 1000 to 5000 GM, following the 2,4,6-tris(thiophen-2-yl)-1,3,5-triazine/fluorene ratio.     

New star-shaped trinuclear Ru(II) polypyridine complexes of imidazo[4,5-f][1,10]phenanthroline derivatives: syntheses, characterization, photophysical and electrochemical properties

A series of new star-shaped trinuclear Ru(II) complexes of imidazo[4,5-f][1,10]phenanthroline derivatives, [{Ru(bpy)(2)}(3){μ-mes(1,4-phO-Izphen)(3)}](ClO(4))(6)·4H(2)O (6), [{Ru(phen)(2)}(3){μ-mes(1,4-phO-Izphen)(3)}](ClO(4))(6)·3H(2)O (7), [{Ru(bpy)(2)}(3){μ-mes(1,2-phO-Izphen)(3)}](ClO(4))(6)·4H(2)O (8), and [{Ru(phen)(2)}(3){μ-mes(1,2-phO-Izphen)(3)}](ClO(4))(6)·3H(2)O (9) [mes(1,4-phO-Izphen)(3) (4) = 2,4,6-tri methyl-1,3,5-tris(4-oxymethyl-1-yl(1H-imidazo-2-yl-[4,5-f][1,10]phenanthroline)phenyl)benzene and (mes(1,2-phO-Izphen)(3) (5) = 2,4,6-trimethyl-1,3,5-tris(2-oxymethyl-1-yl(1H-imidazo-2-yl[4,5-f][1,10]phenanthroline)phenyl)benzene] have been synthesized and characterized. Their photophysical and electrochemical properties have also been studied. The core molecule, 1,3,5-tris(bromomethyl)-2,4,6-trimethylbenzene (1) and the trialdehyde intermediate, 2,4,6-trimethyl-1,3,5-tris(4-oxymethyl-1-formylphenyl)benzene (2) are characterized by single crystal X-ray diffraction: triclinic, P1[combining macron]. The complexes 6-9 exhibit Ru(II) metal centered emission at 618, 601, 615, and 605 nm, respectively, in fluid solution at room temperature. The emission profile and emission maxima are similar and independent of the excitation wavelength for each complex. The complexes 6-9 undergo metal centered oxidation and the E(1/2) values for the Ru(II)/Ru(III) redox couples are 1.33, 1.34, 1.35, and 1.35 V versus Ag/Ag(+), respectively, which are cathodically shifted with respect to that of the mononuclear complex [Ru(bpy)(2)(PIP)](2+) (PIP = 2-phenylimidazo[4,5-f][1,10]phenanthroline). The study demonstrates the versatility of the highly symmetric trinucleating imidazo[4,5-f][1,10]phenanthroline-based core ligands 4 and 5 in forming trinuclear Ru(II) complexes.     

Synthesis and characterization of low molecular mass luminescent liquid crystalline materials with 1,3,4-oxadiazole units

The synthesis, and liquid crystalline and photophysical properties of luminescent liquid crystalline compounds based on 1,3-bis[5-(4-alkoxyphenyl)-1,3,4-oxadiazole-2-yl]benzene (two-fold symmetry) I and 1,3,5-tris[5-(4-alkoxyphenyl)-1,3,4-oxadiazole-2-yl]benzene II (three-fold symmetry) are described. The mesophases were characterized using polarizing optical microscopy and differential scanning calorimetry. In addition, all compounds showed blue fluorescence with emission maxima between 366 and 382 nm, and good quantum yields of photoluminescence (Φ_PL = 45%).     

Synthesis and electrochromic properties of polyimides with pendent benzimidazole and triphenylamine units

Five novel near-infrared electrochromic aromatic polyimides(PIs) with pendent benzimidazole group were synthesized from 4,4'-diamino-4'-(1-benzylbenzimidazol-2-yl)triphenylamine(named as DBBT) with five different dianhydrides via two-step polymerization process, respectively. The maximum UV-Vis absorption bands of these PIs locate at about 335 nm for solid films due to the π-π* transitions. A reversible pair of distinct redox peaks, that were associated with a noticeable color change from original yellow to blue, was observed in the cyclic voltammetry(CV) test. A new absorption peak emerged at 847 nm in near-infrared(NIR) region with increasing voltage in UV-Vis-NIR spectrum, which indicates that PI can be used as NIR electrochromic material. These novel PIs have good electrochemical stability, appropriate energy levels for the highest occupied molecular orbital(HOMO) and the lowest unoccupied molecular orbital(LUMO), in the range of-5.17 e V to-5.20 e V and-2.14 e V to-2.26 e V(versus the vacuum level) determined by cyclic voltammetry method. These values basically consisted with the results of quantum chemical calculation. These polyimides can be used as novel electrochromic and hole transportation materials.     

Efficient greenish blue electrochemiluminescence from fluorene and spirobifluorene derivatives

The spectroscopic and electrochemical behavior as well as electrogenerated chemiluminescence (ECL) of a series of donor-π-donor derivatives bearing triphenylamine groups as donor connected to a fluorene, 2,7-bis-(4-(N,N-diphenylamino)phen-1-yl)-9,9'-dimethylfluorene (1), or spirobifluorene core, 2,7-bis-(4-(N,N-diphenylamino)phen-1-yl)-9,9'-spirobifluorene (2) and 2,2',7,7'-tetrakis(4-(N,N-diphenylamino)phen-1-yl)-9,9'-spirobifluorene (3), were investigated. Besides a high photoluminescence (PL) quantum yield in solution (between 81 and 87%), an efficient radical ions annihilation process induces intense greenish blue ECL emission that could be seen with the naked eye. Only the tetrasubstituted spirobifluorene derivative (compound 3) shows weak ECL obtained by a direct annihilation mechanism. Because the energy of the annihilation reaction is higher than the energy required to form the singlet excited state, the S-route could be considered the pathway followed by the ECL process in these molecules. The ECL emissions recorded by direct ion-ion annihilation show two bands compared to the single structureless PL band. The ECL spectra obtained by a coreactant approach using benzoylperoxide as a coreagent show no differences relative to that produced by annihilation, except for an increasing of ECL intensity for all compounds.     

Novel Iridium Complex with Carbazol-2-yl-β-diketone Derivative: Low-energy Excitation and Red Electrophosphorescent Devices

A novel iridium-complex, (BPPBI)₂Ir(2-TFDBC)[BPPBI=2-(biphenyl-4-yl)-1-phenyl-1H-benzo[d]imi- dazole, 2-TFDBC=1-(9-ethyl-9H-carbazol-2-yl)-4,4,4-trifluorobutane-1,3-dione], was synthesized, and its structure and component were confirmed by ¹H NMR and element analysis, respectively. UV-Vis absorption and photoluminescent(PL) spectra of (BPPBI)₂Ir(2-TFDBC) in dichloromethane were investigated. The Ir-complex exhibited a long wavelength excitation of 470 nm, i.e., low-energy excitation. So, it is a promising candidate for phosphorescent probe and PL material. (BPPBI)₂Ir(2-TFDBC)-based electroluminescent devices, ITO/MoO₃(10 nm)/NPB(80 nm)/ CBP:x(BPPBI)₂Ir(2-TFDBC)(20 nm)/TPBi(45 nm)/LiF/Al, were fabricated, where x(%) was of 4% or 8% doping concentration(mass fraction); ITO=indium tin oxides; NBP=N,N'-bis-(1-naphthalenyl)-N,N'-bis-phenyl-(1,1'-biphenyl)- 4,4'-diamine, CBP=4,4'-bis(N-carbazolyl)-1,1'-biphenyl, TPBi=1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene. The devices showed a red emission of 620 nm. The maximum current efficiency and brightness were 1.7 cd/A and 4063 cd/m² for a device of 8%(mass fraction) doping level, respectively. The moderate luminous efficiency was due to the inadequate energy transfer from the host material to the guest material.     

Electro-functional octupolar π-conjugated columnar liquid crystals

A series of propeller-shaped π-conjugated molecules based on 2,4,6-tris(thiophene-2-yl)-1,3,5-triazines has been designed and synthesized to obtain ambipolar charge-transporting liquid-crystalline materials. The 3-fold electron-donating aromatic units are attached to the electron-accepting triazine core, which forms electro-functional octupolar π-conjugated structures. These octupolar molecules self-organize into one-dimensional columnar nanostructures and exhibit ambipolar carrier transport behavior, which has been revealed by time-of-flight measurements. In this approach, electron-donor and acceptor electro-active segments are assembled individually in each column to give one-dimensional nanostructured materials with precisely tuned electronic properties. Their desirable electronic structures responsible for both hole and electron conductions have also been examined by cyclic voltammetry and theoretical calculations. The present results provide a new guideline and versatile approach to the design of ambipolar conductive nanostructured liquid-crystalline materials.     

Simple Synthesis of Red Iridium(III) Complexes with Sulfur-Contained Four-Membered Ancillary Ligands for OLEDs

Phosphorescent iridium(III) complexes have been widely researched for the fabrication of efficient organic light-emitting diodes (OLEDs). In this work, three red Ir(III) complexes named Ir-1, Ir-2, and Ir-3, with Ir-S-C-S four-membered framework rings, were synthesized efficiently at room temperature within 5 min using sulfur-containing ancillary ligands with electron-donating groups of 9,10-dihydro-9,9-dimethylacridine, phenoxazine, and phenothiazine, respectively. Due to the same main ligand of 4-(4-(trifluoromethyl)phenyl)quinazoline, all Ir(III) complexes showed similar photoluminescence emissions at 622, 619, and 622 nm with phosphorescence quantum yields of 35.4%, 50.4%, and 52.8%, respectively. OLEDs employing these complexes as emitters with the structure of ITO (indium tin oxide)/HAT-CN (dipyra-zino[2,3-f,2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile, 5 nm)/TAPC (4,4′-cyclohexylidenebis[N,N-bis-(4-methylphenyl)aniline], 40 nm)/TCTA (4,4″,4″-tris(carbazol-9-yl)triphenylamine, 10 nm)/Ir(III) complex (10 wt%): 2,6DCzPPy (2,6-bis-(3-(carbazol-9-yl)phenyl)pyridine, 10 nm)/TmPyPB (1,3,5-tri(mpyrid-3-yl-phenyl)benzene, 50 nm)/LiF (1 nm)/Al (100 nm) achieved good performance. In particular, the device based on complex Ir-3 with the phenothiazine unit showed the best performance with a maximum brightness of 22,480 cd m⁻², a maximum current efficiency of 23.71 cd A⁻¹, and a maximum external quantum efficiency of 18.1%. The research results suggest the Ir(III) complexes with a four-membered ring Ir-S-C-S backbone provide ideas for the rapid preparation of Ir(III) complexes for OLEDs.