新型电磷光咔唑-co-吡啶共聚物的合成与发光性能

用Suzuki缩聚反应制备了一系列新型咔唑-吡啶共轭主链上含有金属铱配合物单元的共聚物. 共聚物发光器件结构为ITO/PEDOT:PSS/polymer＋PBD (w＝30%)/CsF/Al [氧化铟锡/苯磺酸掺杂聚乙烯基二氧噻吩/聚合物＋2,4-二苯-5-4-叔丁基苯-1,3,4-恶二唑(w＝30%)/氟化铯/铝]. 基于共聚物PCzPyIrMppy2的器件在电流密度为20.8 mA/cm2时, 最大外量子效率和流明效率分别达到4.1%和6.1 cd/A. 在电流密度200 mA/cm2时, 器件的最大外量子效率和流明效率仍分别达到3.2%和4.8 cd/A, 器件的发光的最大波长位于570 nm, 最大亮度达到13251 cd/m2. 研究结果表明, 在共轭聚合物主链上引入螯合金属铱配合单元是实现高效、稳定的电致磷光器件的有效方法之一.     

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.     

侧链接枝低聚对亚苯基亚乙烯基聚芴衍生物的合成及其电致发光性能

采用Wittig-Horner反应,将少量端基为磷脂的黄光发射客体低聚对亚苯基亚乙烯基链段(MOPV)接枝到含有醛基单体的蓝光发射主体材料聚芴的侧链上,合成了一种新型的接枝聚芴衍生物PF-g-MOPV.这种接枝聚合物具有很好的热稳定性,可溶于常用的有机溶剂.以接枝共聚物PF-g-MOPV为发光层的单层器件发射出黄绿光,色坐标为(0.30,0.57),最大发光亮度达到1550cm/m2,这说明蓝光聚芴主链向侧链MOPV进行了有效地能量转移.     

N-苯基咔唑取代的蓝光聚(2,7-咔唑)的合成与表征

采用Suzuki聚合方法并通过改变催化剂的投料量,合成了一系列具有不同分子量的N-苯基咔唑取代的蓝光聚(2,7-咔唑),并详细研究了分子量对聚合物的光物理、电化学和电致发光器件性质的影响.结果表明,刚性N-苯基咔唑侧链的引入,能够有效地调控主链之间的相互作用,提高蓝光的色纯度,并使得该系列聚合物的固态荧光量子效率高达0.40.同时,在热退火及器件工作过程中,没有观察到类似聚芴中绿光峰的出现,表明具有良好的光谱稳定性.单层聚合物电致发光器件的最大发光效率为0.33 cd/A,色坐标为(0.18,0.12).     

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%.     

一种具有稳定发射光谱的高效率白色有机电致发光器件

报道一种具有稳定发射光谱的新型白色有机电致发光器件. 选择DCJTB 作为红光染料将其掺入空穴传输材料NPB 中作为空穴传输层和第一发光层, 提供蓝光和红光; 选择AlQ 作为电子注入敏化剂, 将其掺入NPB 中作为第二发光层, 提供蓝光和绿光. DCJTB和AlQ 的掺杂浓度分别被优化为0.4%和1.4%, 第二发光层的厚度被优化为3 nm. 最终,得到了纯白色发射的有机电致发光器件; 该器件启亮电压仅3.1 V, 最大亮度高达32749 cd/m², 器件的最大电流效率为8.67 cd/A, 器件的最大功率效率为8.78 lm/W. 而且, 空穴型主体材料的选择导致该器件的色稳定性非常理想. 随着电流密度的提高, 该器件的色坐标始终稳定在(0.343, 0.342)到(0.328, 0.336)的范围内.     

有机电致发光器件中载流子传输与复合的调控

在典型的多异质结器件ITO/NPB/CBP：Ir（ppy）3/Bphen/Alq3/LiF/Al的基础上,利用有机半导体掺杂技术,设计制备了单异质结-单发光层器件、单异质结-p-i-n结构器件、单异质结-双发光层器件及无异质结-混合主体结构器件,并对其光电性能进行了研究和比较.其中,单异质结-p-i-n结构器件的最大功率效率为32.1lm/W,是参考器件的3.1倍,寿命是参考器件的15倍.无异质结-混合主体结构器件的最大功率效率为37.2lm/W,是参考器件的3.5倍,其寿命是参考器件的46倍.研究结果表明,通过对载流子传输层和发光层的优化设计,构建电子、空穴传输平衡的载流子传输层和发光层,减少或取消异质结界面仍可以实现对载流子传输和复合的有效调控,从而使器件的发光效率和寿命同时得到提高.本研究将为高性能OLED的设计提供实验基础.     

带烷氧基的苯基蒎烯吡啶铱配合物在聚合物电致发光器件中的应用研究

采用旋涂法将一组带烷氧基的苯基蒎烯吡啶铱(Ⅲ)配合物(Ir(RO-pppy)₃)磷光材料掺杂到PVK中,制作出了聚合物电致发光器件:ITO/PE-DOT:PSS(40 nm)/PVK_0.7:PBD_0.3:(x%.)Ir-complex(80 nm)/CsF(1.5 nm)/Mg:Ag(200 nm).实验结果表明,带有长烷氧基链配体的铱(Ⅲ)配合物能表现出更好的器件行为,当掺杂浓度为3.2%时,器件的最高发光效率达19.9 cd/A(7.8 lm/W,9.1V),CIE为(0.20,0.56);器件最大亮度为15700 cd/m²(8.4V).通过对这组铱(Ⅲ)配合物的光物理行为及电化学性能的研究,考察了主体材料与配合物之间的能级配置以及能量转移的机理.     

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%.     

基于聚芳醚的双色白光聚合物的合成与光物理及电致发光性能

采用缩聚反应,通过将深蓝光荧光团(五联芴)和橙光荧光团(4-芴基-7-(4-二苯胺基-苯基)-2,1,3-苯并噻二唑)分别链接在聚芳醚的侧链上,合成了一种双色白光电致发光聚芳醚P1,接着将一种高效浅蓝光荧光团(2,7-二(9-乙基-咔唑乙烯基)芴)引入到了P1的侧链上,得到了聚芳醚P2和P3.系统研究了这些聚芳醚材料的溶解性、热稳定性、电化学性能、光物理性能和电致发光性能等.结果表明,所有聚芳醚都具有良好的溶解性与热稳定性;薄膜态时存在明显的由深蓝光荧光团到浅蓝光荧光团及橙光荧光团的能量转移;退火前后的薄膜光致发光光谱基本一致,表明具有优秀的光谱稳定性.基于这些聚芳醚的单层电致发光器件(ITO/PEDOT:PSS/高分子/Ca/Al),利用部分能量转移和电荷俘获作用,可以实现近白光发射.器件的最大电流效率可以达到7.96 cd/A,最大亮度为9950 cd/m2,色坐标为(0.33,0.44).     

Synthesis and properties of electrophosphorescent chelating polymers with iridium complexes in the conjugated backbone

The synthesis of electrophosphorescent chelating polymers by Suzuki polycondensation of A-A- and B-B-type monomers is described, in which the fluorene-alt-carbazole (PFCz) segment is used as polymer backbone. By using alkyl-substituted ligands of iridium complex monomers, chelating copolymers with higher contents of iridium complex can be synthesized. Chemical and photophysical characterization confirm that the Ir complex is incorporated into the polymer backbone as one of the monomer repeat units by means of two 5-bromotolylpyridine ligands. Chelating polymers with Ir complexes in the conjugated polymer backbone show highly efficient energy transfer of excitons from the PFCz host segment to the Ir complex by an intramolecular trapping mechanism. The external quantum and luminous efficiencies of a device made with PFCzMppyIrhm4 copolymer reach 4.1 % ph/el (photons/electron) and 5.4 cd A(-1), respectively, at a current density of 32.2 mA cm(-2), an emission peak of 577 nm, and a luminance of 1730 cd cm(-2). Most important, the devices made from the chelating copolymers show no notable efficiency decay with increasing current density due to reduced concentration quenching and triplet-triplet (T-T) annihilation. This indicates that incorporation of the phosphorescent complex into the rigid conjugated polymer main chain is a new way to simultaneously realize high efficiency, long-term stability, and simple processing of phosphorescent polymer light-emitting diodes.     

Synthesis, characterization and photophysics of fluorene-alt-oxadiazole copolymers containing pendent iridium (III) complex moiety

A series of fluorene-alt-oxadiazole copolymers containing a pendent phosphor chromophore of the (piq)₂Ir(pic) complex were synthesized via the palladium-catalyzed Suzuki coupling reaction, where piq is 1-phenylisoquinoline and pic is picolinic acid. These copolymers exhibited a similar absorption spectrum with a peak at about 330 nm and a typical emission peak at 408 nm in CH₂Cl₂ from the fluorene-alt-oxadiazole backbone. However, a significantly red-shifted emission peak at about 625 nm was observed in the neat films of these copolymers, which are attributed to the pendent iridium (III) complex unit. Using these copolymers as single emission layer, the polymer light-emitting devices with a configuration of ITO/PEDOT:PSS/copolymers/LiF/Al exhibited a saturated red emission with a peak at 632 nm. Significant influence of the attached iridium (III) complex ratio on EL performance was presented. A maximum current efficiency of 1.2 cd/A at 63 mA/cm² and a maximum luminance of 1125 cd/m² at 12 V were achieved from the device with the copolymer containing iridium (III) complex in a 3% molar ratio.     

Triplet energy back transfer in conjugated polymers with pendant phosphorescent iridium complexes

The nature of Dexter triplet energy transfer between bonded systems of a red phosphorescent iridium complex 13 and a conjugated polymer, polyfluorene, has been investigated in electrophosphorescent organic light-emitting diodes. Red-emitting phosphorescent iridium complexes based on the [Ir(btp)(2)(acac)] fragment (where btp is 2-(2'-benzo[b]thienyl)pyridinato and acac is acetylacetonate) have been attached either directly (spacerless) or through a -(CH(2))(8)- chain (octamethylene-tethered) at the 9-position of a 9-octylfluorene host. The resulting dibromo-functionalized spacerless (8) or octamethylene-tethered (12) fluorene monomers were chain extended by Suzuki polycondensations using the bis(boronate)-terminated fluorene macromonomers 16 in the presence of end-capping chlorobenzene solvent to produce the statistical spacerless (17) and octamethylene-tethered (18) copolymers containing an even dispersion of the pendant phosphorescent fragments. The spacerless monomer 12 adopts a face-to-face conformation with a separation of only 3.6 A between the iridium complex and fluorenyl group, as shown by X-ray analysis of a single crystal, and this facilitates intramolecular triplet energy transfer in the spacerless copolymers 17. The photo- and electroluminescence efficiencies of the octamethylene-tethered copolymers 18 are double those of the spacerless copolymers 17, and this is consistent with suppression of the back transfer of triplets from the red phosphorescent iridium complex to the polyfluorene backbone in 18. The incorporation of a -(CH(2))(8)- chain between the polymer host and phosphorescent guest is thus an important design principle for achieving higher efficiencies in those electrophosphorescent organic light-emitting diodes for which the triplet energy levels of the host and guest are similar.     

以铱配合物为核、3,6-咔唑为枝的超支化电磷光聚合物的合成与发光性能

采用Suzuki缩聚反应制备了以铱配合物为核、3,6-咔唑为枝的超支化电磷光聚合物(PCzIrMppy1和PCzIrMppy3). 超支化聚合物PCzIrMppy3的光致发光量子效率为62%, HOMO能级为-5.22 eV, 接近阳极ITO/PEDOT∶PSS的能级(-5.20 eV), 表明其优异的空穴注入性能. 以PCzIrMppy3聚合物为发光层制备的绿光电磷光电致发光器件ITO/PEDOT∶PSS/Emissive layer/CsF/Al的最大电流效率为10.4 cd/A, 最大亮度为34758 cd/m². 此外, 器件的效率随电流密度的衰减较慢, 说明这种超支化结构可有效减少高电流密度下的浓度猝灭.     

Synthesis and characterization of electrophosphorescent jacketed conjugated polymers

A monomer containing bent side chains with oxadiazole unit was synthesized. And it was copolymerized with polyfluorene at different ratios. The photophysical and electrochemical properties of the copolymers were characterized. The results show that the introduction of the oxidiazole‐containing side chains into the polymer reduces the lowest unoccupied molecular orbital level. And the steric hindrance of the side groups can effectively suppress the aggregation of the polymer backbones. Electroluminescent devices were fabricated with a configuration of indium tin oxide (ITO)/poly(3,4‐ethylenedioxythiophene (PEDOT):PSS/Sample/Ca/Al. All of the devices emit blue light. The device of the copolymer PFOXD50 shows the best performance with the maximum luminance of 1033 cd/m² and the maximum current efficiency of 0.29 cd/A. Then a cyclometalated iridium complex monomer (ppy)₂Ir(BrPhPyBr) was copolymerized with PFOXD50 at different ratios. The devices with the same configuration emit orange light. The efficiency generally increases with the increasing Ir content. Among them, the device of the copolymer PFOXDIr7 shows the best performance with the maximum luminance of 846 cd/m² and the maximum current efficiency of 0.61 cd/A. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and Antibacterial Activity of Selenium-functionalized Poly(ε-caprolactone)

A selenium-functionalizedε-caprolactone was synthesized by introducing a phenyl selenide group at the 7-position.A polymer was obtained through the ring-opening polymerization of this monomer in a base/thiourea binary organocatalytic system.A living polymerization process was achieved under mild conditions.The resulting polymers had a controlled molecular weight with a narrow molecular weight distributions and high end-group fidelity.Random copolymers could be obtained by copolymerizing this monomer withε-caprolactone.The thermal degradation temperature of the obtained copolymers decreased with the increasing molar ratio of selenide functionalized monomer in copolymers,while the glass transition temperature increased.In addition,the phenyl selenide side group could be further modified to a polyselenonium salt,which resulted in a polymer with good antibacterial properties.The survival rate of E.coli and S.aureus was only 9%with a polymer concentration of 62.5μg/mL.     

Synthesis of phosphorescent iridium-containing acrylic monomers and their room-temperature polymerization by Cu(0)-RDRP

A series of acrylic monomers based on cyclometalated iridium(III) complexes have been synthesized based on common phosphorescent emitters for organic light-emitting diodes. A simple room-temperature polymerization procedure for these materials was developed using Cu(0) reversible deactivation radical polymerization, providing polymers with low dispersities of 1.08–1.14 at conversions from 81 to 93% when the Ir complexes are copolymerized with a carbazole-based acrylic host. These methods were also found to be suitable for the preparation of high-molecular-weight polymers with M _n approaching 40,000 Da, as well as block copolymers formed in one pot from the chain extension of methyl acrylate. This scalable room-temperature synthesis of iridium-containing copolymers and block copolymers provides a useful route to optoelectronic materials, which we anticipate can be readily adapted to a broad range of acrylic metallopolymers. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2539–2546     

Synthesis and optical properties of white phosphorescent carbazole - iridium copolymers

A series of novel carbazole-iridium copolymers have been designed and synthesized by the combination of blue-emitting acrylate carbazole M1 with hole transporting property and yellow-emitting cyclometalated iridium complex M2 containing 2-phenylpyridine as main ligand and acrylic acid as auxiliary ligand. The results showed that the blue carbazole host resulted in an efficient energy transfer to the yellow iridium complex guest, and when the feed molar ratio of M1 to M2 was 99:1, the emission spectrum of the copolymer presented a broad peak emission which can cover the whole visible range from 400 to 700 nm to obtain a nearly white copolymer material with the CIE coordinates of (0.30, 0.31), as a consequence of polymerized units luminescence, host-guest energy transfer and conjugation degree. Nevertheless, the host-guest energy transfer resulted in green emission about 524 nm of copolymer as the proportion of iridium complex monomer increased. The fluorescence quantum yields of the copolymers were significantly improved compared to the iridium complex monomer.     

不同低聚乙二醇链长的聚对亚苯基亚乙烯基类交替型发光共聚物

合成了3种分子主链由1,4二苯乙烯基苯(DSB,聚对亚苯基亚乙烯基PPV三单元的低聚物)与不同长度的离子传导型隔离链段低聚乙二醇(OEO,或聚氧乙烯)组成的交替型蓝色发光共聚物DSB二缩三乙二醇(TEO)、DSB五缩六乙二醇(SEO)和DSBPEG1500.研究了3种聚合物在其氯仿溶液中的电荷传输机理.通过多种手段考察了不同长度的OEO链段对聚合物的结晶能力、相结构以及其对锂盐溶解能力的影响,并讨论了此类材料的合理结构设计原则.以DSBTEO为发光层材料,装配了电致发光器件.     

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.