含1,1-二（4-（N,N-二甲基胺基）苯基）-2,3,4,5-四苯基噻咯的聚合物在三种阴极结构中的电致发光性能

设计合成了一种1,1-位为二（4-（N,N-二甲基胺基）苯基的新型噻咯单体,并与2,7-芴单体聚合得到六苯基噻咯单体投料量为1%、10%、20%的三种共聚物PF-N-HPS1～20.研究了这些共聚物的紫外吸收光谱、电化学性质、光致发光光谱和电致发光性能.PF-N-HPS的HOMO能级为5.25～5.58eV,呈现绿光发射.以PF-N-HPS为发光层,制作了三种聚合物发光二极管（器件结构A：ITO/PEDOT/PF-N-HPS/Al;器件结构B：ITO/PEDOT/PF-N-HPS/Ba/Al;器件结构C：ITO/PEDOT/PF-N-HPS/TPBI/Ba/Al）.其中器件结构A的电致发光效率仅为0.1～0.33cd/A,说明PF-N-HPS中的4-（N,N-二甲基胺基）苯基结构不能使单独的Al阴极实现良好的电子注入.采用了低功函金属Ba阴极的器件结构B能改善电子的注入,使电致发光效率提高到0.85～1.44cd/A.器件结构C采用TPBI（HOMO：6.2eV）作为电子传输和空穴阻挡层,促进了电子和空穴的有效复合,进一步提高了电致发光效率（4.56～7.96cd/A）,其中TPBI层将噻咯聚合物与金属阴极隔离可能减少发光层在阴极界面处的激子猝灭也起到了一定的作用,器件结构C较器件结构B还获得了更好的绿光光谱.     

含胺烷基侧链的共轭磷光聚芴的合成、表征及其光电性能研究

通过Suzuki聚合反应合成了一种新型的含磷光单元的主链型聚芴类聚合物, 对其进行了表征分析, 并且研究了其在薄膜状态下的光学性质. 在以这种聚合物作为电致发光器件的发光层时, 用高功函数金属铝(Al)作为器件阴极时可以获得和用低功函数金属钡(Ba)作为阴极时相当的器件性能.     

胺基功能化咔唑共轭聚合物的合成及其光电性能研究

发展了新型含有胺基的支化烷基修饰的咔唑单元,并且与芴、咔唑、苯等单元通过Suzuki偶联反应共聚得到不同主链结构的水/醇溶共轭聚合物界面修饰材料,研究了主链结构的变化对材料光物理、电化学性能的影响.所有聚合物均被用作阴极界面材料应用于器件结构为ITO/PEDOT：PSS/P-PPV/界面层/Al的聚合物发光二极管中.在相同器件制备条件下,系统比较了不同主链结构的界面修饰材料在器件中的性能,并研究了性能差异的原因.器件研究结果表明,在高功函数金属Al阴极的聚合物发光二极管中,含胺基功能化咔唑单元的水/醇溶共轭聚合物材料由于界面偶极的形成,均表现出很好的电子注入/传输性能,与之对应的器件性能得到大幅提升.     

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%.     

以碱金属盐为阴极界面层的有机光电器件的制备及性能

以碱金属盐Li F,Na F,Cs F和Cs2CO3作为阴极界面材料,制备了高效率有机小分子电致发光二极管(SMOLEDs)、聚合物电致发光二极管(PLEDs)及聚合物太阳能电池(PSCs).在SMOLEDs和PLEDs中,Cs F作为阴极界面层的器件流明效率和功率效率最高.在以聚对苯乙烯撑(P-PPV)为发光层的PLEDs中,Cs F作为阴极界面层的器件最大流明效率可达17.85 cd/A,比Li F作为阴极界面层的器件流明效率提高近300%.在以聚(3-己基噻吩)(P3HT)∶[6,6]-苯基-C61-丁酸甲酯(PC61BM)为活性层的PSCs中,当Li F为阴极界面层时,器件功率转换效率(PCE)可达4.12%.而以Na F,Cs2CO3和Cs F为阴极界面层时,PCE分别为3.72%,3.55%和3.2%.这是因为从上述碱金属盐中分解出来的碱金属原子扩散进入器件的有机层并对有机层进行了n型掺杂,影响了器件的电流密度和效率.     

绿色单峰发光聚(9,9-二烯丙基芴)的合成及其发光机制

为了得到绿色单峰发光的聚合物材料, 我们设计并合成了9位取代的二烯丙基芴单体, 在NiCl₂的催化下, 合成了可溶的聚芴衍生物, 聚(9,9-二烯丙基芴)(PAF). 较短的烯丙基链既可以增加聚芴的溶解度, 双键的存在又有利于聚芴发生分子间聚集而得到绿光发射的有机电致发光器件(OLED). PAF在溶液和薄膜状态下的荧光峰分别位于403和456 nm的蓝光区域, 而其器件ITO/PEDOT:PSS/PAF/LiF/Al(其中, ITO为氧化铟锡, PEDOT为聚(3,4-乙撑二氧噻吩), PSS为聚苯乙烯磺酸盐)的电致发光峰却红移至绿光区域(532 nm), 得到绿色单峰发光. 紫外吸收光谱、荧光发射光谱、红外光谱以及原子力显微镜(AFM)图像的结果证明, 造成PAF电致发绿光的机制为聚合物分子间聚集.     

含有萘并噻二唑的红光电致发光聚合物的合成和性能研究

以2,7-二溴-9,9-双(N,N-二甲基丙胺基)芴与4,7-双(5-溴-2-噻吩)-2,1,3-萘并噻二唑为共聚单体, 通过Suzuki偶合反应合成按不同比例共聚的一系列共轭聚合物, 并对它们的电致发光性能进行了研究. 结果表明, 所有的聚合物均在高功函数金属铝作阴极的器件中具有较高的发光效率, 最大电致发光外量子效率为1.3%, 好于目前广泛应用的低功函数金属(如钡, 钙等)作阴极的发光效率.     

含苯并硒二唑聚咔唑/芴类共轭聚电解质及其前驱体的合成与性能研究

采用Suzuki偶合反应合成了一系列新型的咔唑、芴和2,1,3-苯并硒二唑的共聚物——聚[3,6-(N-(2-乙基己基))咔唑-2,1,3-苯并硒二唑-9,9-双(N,N-二甲基胺丙基)芴](PCzN-BSeD)及其相应的聚电解质衍生物——聚[3,6-(N-(2-乙基己基))咔唑-2,1,3-苯并硒二唑-9,9-(双(3′-(N,N-二甲基)-N-乙基铵)丙基)芴]二溴(PCzNBr-BSeD).在聚咔唑和芴中引入不同比例的2,1,3-苯并硒二唑(BSeD)单元,引起了由咔唑和芴链段向窄带隙苯并硒二唑(BSeD)单元有效的能量转移.通过对聚合物电致发光性能的研究,发现用聚(3,4-亚乙基二氧基噻吩)(PEDOT)或聚(3,4-亚乙基二氧基噻吩)/聚乙烯咔唑(PEDOT/PVK)作为空穴传输层时,器件的性能相差不大,表明咔唑的引入较明显的改善了聚合物的空穴注入性能.而且几乎所有的聚合物用高功函数铝作阴极的器件和用钡/铝作阴极的器件具有相近的发光性能,表明这类聚合物具有良好的电子注入性能.     

吡唑啉衍生物有机电致发光器件中激基复合物的发射

以两种吡唑啉衍生物为空穴传输材料(HTM)和BBOT为电子传输材料组成双层器件, 获得了相对于组成材料的荧光光谱红移和宽化的电致发光. 双层器件和HTM∶BBOT等摩尔混蒸薄膜的光致发光及电致发光测量表明, 该谱带来自HTM/BBOT界面激基复合物的发射, 根据器件的能级图, 激基复合物的类型为BBOT的激发态BBOT⁽与基态的HTM相互作用的复合物. 用HTM∶BBOT混合发光层增加器件中激基复合物的形成界面, 提高了器件的发射性能.     

基于不同辅助配体螯合电磷光聚合物的合成与性能研究

通过A-A, B-B型的Suzuki缩聚反应将三个具有不同辅助配体的2-(2'-苯并[b]噻吩)吡啶(btp)双环铱金属配合物引入芴和咔唑交替共聚物(PFCz)的主链上, 合成一系列最大发光波长在660 nm的红光螯合电磷光聚合物, 并研究了它们的电致发光性能. 实验证明了在这类电磷光聚合物中配合物单元辅助配体合理的分子设计, 可以提高配合物单体的溶解度, 提高聚合物的分子量和发光性能. 通过优化器件结构, 聚合物PFBtpIrf5单层器件(ITO/PEDOT:PSS/polymer＋PBD(30 wt%)/Ba/Al)的性能最好: 在电流密度为14.3 mA/cm²时, 最大外量子效率为1.93%.     

Electroluminescence performances of 1,1-bis(4-(N,N-dimethylamino)phenyl)-2,3,4,5-tetraphenylsilole based polymers in three cathode architectures

A new silole monomer with two 4-(N,N-dimethylamino)phenyl substitutions on silicon atom as designed and synthesized.Three copolymers PF-N-HPS1,PF-N-HPS10 and PF-N-HPS20 were then obtained by copolymerizations of 2,7-fluorene derivatives with the silole monomer at feed ratios of 1%,10%,and 20%.Their UV-vis absorption,electrochemical,photoluminescent,and electroluminescent (EL) properties were investigated.PF-N-HPS possessed HOMO levels of 5.25-5.58 eV,and showed green emissions.Using PF-N-HPS as the emissive layer,three different polymer light-emitting diodes were fabricated as device A with ITO/PEDOT/PF-N-HPS/Al,device B with ITO/PEDOT/PF-N-HPS/Ba/Al,and device C with ITO/PEDOT/PF-N-HPS/TPBI/Ba/Al.For the device A,PF-N-HPS only showed very low EL efficiency of 0.06-0.33 cd/A,indicating that the Al cathode could not inject electron efficiently to the emissive polymers containing the 4-(N,N-dimethylamino)phenyl groups.For the device B,low work function Ba supplied better electron injections,and the EL efficiency could be improved to 0.85-1.44 cd/A.TPBI with a deep HOMO level of 6.2 eV could enhance electron transport and hole blocking.Thus modified recombinations and largely elevated EL efficiency of 4.56-7.96 cd/A were achieved for the device C.The separation of the emissive layer and metal cathode with the TPBI layer may also suppress exciton quenching at the cathode interface.     

高效溶液法小分子磷光电致发光器件研究

以小分子化合物CDBP[4,4′-bis(carbazol-9-yl)-9,9-dimethyl-fluorene]为主体材料,Ir(pppy)3[tris(5-phenyl-10,10-dimethyl-4-aza-tricycloundeca-2,4,6-triene)Iridium(III)]为磷光客体材料,采用溶液法和真空蒸镀法相结合的制备工艺,制作了小分子磷光电致发光器件.研究表明,通过器件结构的优化,Ir(pppy)3(重量百分比为2)掺杂的多层绿光电致发光器件效率达22.0 cd/A,最大亮度达到26600 cd/m²,这一结果可与当今基于真空蒸镀的小分子或基于溶液法的高分子磷光电致发光器件性能相媲美.本工作为降低有机电致发光器件的成本,扩展溶液法有机电致发光器件制备工艺中材料的选择范围提供了实验依据.     

Synthesis and optoelectronic properties of amino-functionalized carbazole-based conjugated polymers

A series of alcohol soluble amino-functionalized carbazole-based copolymers were synthesized via Suzuki coupling reaction.The pendent amino groups endow them high solubility in polar solvents,as well as efficient electron injection capability from high work-function metals.The relationships between the photophysical and electrochemical properties and the polymer backbone structure were systematically investigated.These alcohol-soluble carbazole-based copolymers were used as cathode interlayers between the high work-function metal Al cathode and P-PPV emissive layer in polymer light-emitting diodes with device structure of ITO/PEDOT:PSS/P-PPV/interlayer/Al.The resulting devices exhibited improved performance due to the better electron injection/transporting ability of the designed copolymers from Al cathode to the light-emitting layer.     

超薄铝/碳酸锂修饰氧化铟锡阴极制备蓝色磷光反转底发光有机发光二极管

在氧化铟锡（ITO）阴极上依次蒸镀2 nm铝和2 nm碳酸锂（Li2CO3）薄膜作为电子注入层,成功制备出器件结构为ITO/Al/Li2CO3/SPPO13/SPPO13∶FIrpic/TCTA/MoO3/Al(SPPO13：2,7-双（二苯基磷）-9,9′-螺二[芴];FIrpic：双(4,6-二氟苯基吡啶-N,C2)吡啶甲酰合铱;TCTA：4,4′,4″-三(咔唑-9-基)三苯胺)的蓝色磷光反转底发光有机发光二极管（IBOLED）。 结果表明,Al/Li2CO3作为电子注入层可以有效降低ITO与有机材料之间的电子注入势垒,蓝色磷光IBOLED的起亮电压由11 V降至4.2 V,器件的发光效率也得到有效提高。 蓝光磷光IBOLED的最大电流效率与功率效率分别达到了28.2 cd/A和19.6 lm/W,制备出的反转结构器件性能可与传统正置结构比美,说明Al/Li2CO3可以作为反转有机发光二极管优良的电子注入层。     

High-efficiency red-light emission from polyfluorenes grafted with cyclometalated iridium complexes and charge transport moiety

We report a new route for the design of electroluminescent polymers by grafting high-efficiency phosphorescent organometallic complexes as dopants and charge transport moieties onto alky side chains of fully conjugated polymers for polymer light-emitting diodes (PLED) with single layer/single polymers. The polymer system studied involves polyfluorene (PF) as the base conjugated polymer, carbazole (Cz) as the charge transport moiety and a source for green emission by forming an electroplex with the PF main chain, and cyclometalated iridium (Ir) complexes as the phosphorescent dopant. Energy transfer from the green Ir complex or an electroplex formed between the fluorene main chain and side-chain carbazole moieties, in addition to that from the PF main chain, to the red Ir complex can significantly enhance the device performance, and a red light-emitting device with the high efficiency 2.8 cd/A at 7 V and 65 cd/m2, comparable to that of the same Ir complex-based OLED, and a broad-band light-emitting device containing blue, green, and red peaks (2.16 cd/A at 9 V) are obtained.     

Creating a pseudometallic state of K+ by intercalation into 18-crown-6 grafted on polyfluorene as electron injection layer for high performance PLEDs with oxygen- and moisture-stable Al cathode

Polymer light-emitting diodes (PLEDs) suffer from inadequate lifetimes because of the use of environmentally sensitive metals as the cathodes. We present the use of water/methanol-soluble polyfluorene grafted with 18-crown-6 chelating to K(+) as the electron-injection layer (EIL) for deep-blue-emission PLEDs, allowing the use of environmentally stable Al as the cathode since electron donation from the 18-crown-6 can reduce K(+) to a stable "pseudometallic state", enabling it to act as an intermediate step for electron injection. Furthermore, when poly(ethylene oxide) was blended into the EIL to provide hole blocking (HB), the device exhibited the highest performance reported to date for a deep-blue-emission PLED based on a conjugated polymer as the emitting layer, with a brightness of 54,800 cd/m(2) and an external quantum efficiency of 5.42%. The use of such an EI-HB layer opens a broad avenue leading toward industrialization of PLEDs.     

Synthesis and characterization of blue light-emitting poly(aryl ether)s containing pyrimidine-incorporated oligofluorene pendants with bipolar feature

Novel blue light-emitting poly(aryl ether)s comprising of bipolar oligofluorene pendants as chromophores have been designed and synthesized,in which pyrimidine and arylamine moieties are utilized as the electron acceptor and electron donor,respectively.Through varying π bridge length from monofluorene to bifluorene and end-cappers from hydrogen to carbazole and diphenylamine,the emission color of the resulting polymers covers from deep blue to greenish blue,and their HOMO and LUMO levels can be modulated to facilitate charge injection to improve the device performance.Polymer lightemitting diodes(PLEDs) are fabricated with the device structure of ITO/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)(PEDOT:PSS)(50 nm)/polymer(80 nm)/Ca(10 nm)/Al(200 nm).Among these polymers,P2Cz5F-Py with bifluorene bridge and carbazole end-capper shows excellent trade-off between the efficiency and emission wavelength,having a peak luminous efficiency as high as 1.26 cd/A and Commission Internationale de L’Eclairage(CIE) coordinates of(0.17,0.17).     

Copolyfluorenes containing pendant bipolar carbazole and 1,2,4‐triazole groups: Synthesis,characterization, and optoelectronic applications

Three novel copolyfluorenes ( P1 ‐ P3 ) containing pendant bipolar groups (2.5–7.7 mol %), directly linked hole‐transporting carbazole and electron‐transporting aromatic 1,2,4‐triazole, were synthesized by the Suzuki coupling reaction and applied to enhance emission efficiency of polymer light‐emitting diodes based on conventional MEH‐PPV. The bipolar groups not only suppress undesirable green emission of polyfluorene under thermal annealing, but also promote electron‐ and hole‐affinity of the resulting copolyfluorenes. Blending the bipolar copolyfluorenes with MEH‐PPV results in significant enhancement of device performance [ITO/PEDOT:PSS/MEH‐PPV+ P1 , P2 or P3 /Ca(50 nm)/Al(100 nm)]. The maximum luminance and luminance efficiency were enhanced from 3230 cd/m² and 0.29 cd/A of MEH‐PPV‐only device to 15,690 cd/m² and 0.81 cd/A (blend device with MEH‐PPV/ P3 = 94/6 containing about 0.46 wt % of pendant bipolar residues), respectively. Our results demonstrate the efficacy of the bipolar copolyfluorenes in enhancing emission efficiency of MEH‐PPV. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Aggregation-enhanced emission and efficient electroluminescence of conjugated polymers containing tetraphenylethene units

Tetraphenylethene (TPE) is a popular luminogen characterized by aggregation-induced emission and has been widely used to construct solid-state emissive materials. In this work, two thermally stable polymers (P1 and P2) consisting of TPE conjugated to the 2,7-positions of fluorene and carbazole, respectively, are synthesized and characterized. Both polymers are weakly fluorescent in solutions but show greatly enhanced emission as the aggregate formation, presenting an aggregation-enhanced emission feature. Two kinds of polymer light-emitting diodes are fabricated utilizing P1 and P2 as emitters (EML) (device I: ITO/PEDOT:PSS (45 nm)/PVK:EML (1:1 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag; device II: ITO/PEDOT:PSS (45 nm)/ PVK:OXD-7:EML (3:1:3 wt%, 55 nm)/TPBI (38 nm)/Ca:Ag). The device II of P2 shows the best performances, affording a maximum luminance of 6500 cd/m 2 and a high peak efficiency of 2.11 cd/A.