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（carbazo1．9-yl）-9，9-dimethyl-fluorene]为主体材料，Ir（pppy）3[tris（5-phenyl-10，10-dimethyl-4-aza—tficycloundeca-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22．0cd／A，最大亮度达到26600cd／m^2，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．     

镉配合物[Cd（2，2-bipy）（NaN3）2]n的水热合成、晶体结构及热稳定性

在水热法条件下,以N,N-二甲基甲酰胺（DMF）、无水乙醇（EtOH）和水[y（DMF）：V（EtOH）：V（H2O）=3-1：1]为溶剂,基于2,2-联吡啶（2,2-bipy）、叠氮钠（NaN,）和硝酸镉（Cd（NO3）2·4H2O）合成了一维链状超分子配合物[cd（2,2-bipy）（NaN3）2]。（1）。晶体结构分析表明：该配合物属于三斜晶系,c2／c空间群,在不对称结构单元中一个镉原子与两个NaN,中的两个氮原子和2,2-bipy中的两个氮原子配位。同时,配合物（1）通过分子间氢键和π-π堆积作用形成三维超分子。晶胞参数：a=1．21675（5）nm、b=1．4631（6）nm,c=0．6565（2）nm,V=1．1682（8）nm^3,De=2005kg／m^3,Z=4,F（000）=688,GooF：1．138,R1=0．0234,wR2=0．0574。     

两种皮考林酸钴配合物的水热合成及其晶体结构

氯化钴与皮考林酸（Hpie）通过水热反应合成了两种配合物【Co（pic）2（H2O）2】·2H2O（1）和【Co（pic）3】·H2O（2）,其中pic=C6H4O2N。晶体结构均属单斜晶系,空间群和晶胞参数分别为（1）：P2（1）／n,a=0．98618（12）nm,b=0．52101（7）nm,c=1．46289（18）nm,β-90．2440（10）°,V=0．75164（16）nm^3,Z=2,Rl=0．0209,wR2=0．0583;配合物中丰富的氢键构筑起二维超分子网络。（2）C2／c。α=2．9873（3）nm．b=0．85837（8）nm,e=1．38668（13）nm,β=95．8740（10）°V=3．5370（6）nm^3,Z=8．Rl=0．0253,wR2=0．0650：该配合物借助氢键和芳环堆积作用形成二维超分子网络。     

β-二酮类铱配合物的合成、表征及光电性能测试

以5-甲基-2-苯基吡啶（CH3ppy）为主配体，3,7-二乙基-4,6-壬二酮（detd）、2,2,6,6-四甲基-3，5-庚二酮（tmd）和乙酰丙酮（acac）为辅助配体（LX），设计合成了三种含-二酮类辅助配体的绿色磷光金属铱配合物（Ⅲ,Ⅳ,Ⅴ）。通过1HNMR和元素分析对其结构进行了表征，通过UV-vis光谱和荧光发射光谱（PL）测得化合物Ⅲ、IV、V的最大吸收波长范围在250 nm~280 nm之间，最大发射波长分别为530.8 nm、534.2 nm和524.8 nm。制备了器件结构为：ITO/HAT-CN (15nm)/TAPC (50nm)/TCTA (5nm)/TCTA:X (8%,15 nm)/Bepp2 (35nm)/LiF (1nm)/Al (150nm)的有机发光二极管（OLEDs）。结果表明，以化合物Ⅲ制备的器件亮度可以达到59125.2 cd/m2，最大外量子效率为15.0%，最大电流效率为53.8 cd/A，最大功率效率为62.1 lm/W，色坐标（0.30，0.62），是三个器件中综合性能最好的。     

一维CdII超分子配合物的合成及结构

在水-甲醇混合溶剂体系中,以四溴代对苯二甲酸（H2TBTA）及邻菲咯啉（phen）为配体,得到一个超分子配合物{[cd（phen）：（TBTA）]（H2O）（CH3OH）}n（1）,并用元素分析、x-射线单晶衍射及热重分析对其进行了表征。结果分析表明,配合物1属于三斜晶系,P-1空间群,n=9．4774（7）A,b=10．7306（8）A,c=17．1542（13）A,V=1653．4（2）A^3,Z=2,Dcacl=2．014mg／mm^3,R1[I〉2σ（,）]=0．0372,wR2（all data）=0．0750。配合物1通过氢键作用及π-π相互作用构筑成三维超分子。     

二聚5，6-二氧代-1，10-邻菲咯啉配合物的合成及结构分析

利用水热反应合成了聚5,6-二氧代-1,10-邻菲咯啉配合物晶体。同时利用X射线单晶衍射对标题化合物进行了表征。晶体数据：单斜晶系,空间群P2（1）／c,a=1．7365（4）nm,b=1．0961（2）nm,c=1．4424nm,β=111．75（3）°,V=2．5501（9）nm3,Dc=1．470mg／m3,Z=4,F（000）=1168,最终残差因子R1=0．0445,wR2=0．1053,对于全部数据R1=0．0915,wR2=0．1198。     

配合物Ni（2-mpac）2（H2O）2的晶体结构与热稳定性

以2-甲基-5-羧基吡嗪为配体合成了一个镍的单核配合物Ni（2-mpae）2（H2O）2（1）（2-mpae：2-甲基-5-羧基吡嗪）,并利用元素分析,红外光谱,单晶X-射线衍射以及热重分析对配合物（1）进行了表征。晶体学数据：（1）：三斜晶系,P-1空间群,a=0．51403（7）nm,b=0．636．91（8）nm,c=1．2315（2）nm,α=10．3610（1）nm,β=9．1081（2）nm,γ=10．8286（2）nm,V=0．37020（8）nm^3,Z=1,S=1．010,最终残差因子（I〉2σ（I））R1=0．0409,wR2=0．1056,对于全部数据R1=0．0435,wR2=0．1078。     

新型红色磷光铱（Ⅲ）配合物的合成及表征

以2-（2’-苯并噻吩基）吡啶（btp）、对乙烯基苯甲酸（VBA）为原料,通过与水合三氯化铱（IrCl3·3H2O）配合,得到了一种新型铱（Ⅲ）配合物Ir（btp）2（VBA）,通过元素分析、FT—IR光谱及^1HNMR谱对其进行了结构表征,并研究了其UV—Vis吸收光谱和光致发光光谱。结果表明,配合物在403和462nm处存在单重态和三重态的吸收峰,在630nm处有较强的金属配合物三重态的磷光发射峰,是一种新型红色磷光材料。     

邻羟基苯乙酮苯甲酰腙镍、铬配合物的合成、晶体结构及热稳定性

采用水热法和自然挥发法,邻羟基苯乙酮苯甲酰腙与过渡金属Ni（Ⅱ）、Cr（Ⅲ）反应,合成2种新型配合物。通过X射线单晶衍射对配合物结构进行了表征。配合物1：晶体为单斜晶系,C2/c空间群,晶胞参数a=1.5853（3）nm,b=1.16643（19）nm,c=1.8928（3）nm,β=90.00°,V=3.5000（10）nm3,Z=8,Dc=1.484g.cm-3。配合物2：晶体为四方晶系,I4122空间群,晶胞参数a=1.2272（4）nm,b=1.1098（4）nm,c=1.8849（6）nm,β=90.00°,V=2.5671（15）nm3,Z=4,Dc=1.445g.cm-3。配合物1的中心金属离子Ni（Ⅱ）与周围2个氧原子和2个氮原子形成平面几何构型。配合物2的中心金属离子Cr（Ⅲ）与周围4个氧原子和2个氮原子配位形成畸变的八面体配位构型。并利用热失重法分析研究了配合物的热稳定性。     

氮杂环苯基吡啶类铱配合物合成及器件性能

通过对2-甲基-8-(2-吡啶基)苯并呋喃[2,3-B]吡啶辅助配体进行修饰,在吡啶的4号位引入吸电子基团苯基,并对其进行全氘代,同时对5-甲基-2-对甲苯基吡啶主配体的两个甲基进行全氘代,分别合成了两种铱磷光配合物Ⅳ和Ⅳ-d₂₀,采用元素分析、质谱和核磁共振氢谱对其结构进行了表征与确认。利用UV-Vis 光谱、荧光发射光谱(PL)和循环伏安法对其光物理性质及能级结构进行了研究。结果表明：铱配合物的Ⅳ和Ⅳ-d₂₀光致发光光谱发射波长分别为546.85nm和548nm;它们的HOMO和LUMO能级分别为-5.237ev和-2.645ev、-5.082ev和-2.50ev,都是潜在的黄绿色磷光材料。以铱配合物Ⅳ和Ⅳ-d₂₀为客体,制备了结构为ITO/HT:NDP-9(100nm,2%)/HT(130nm)/EB(10nm)/GH:化合物Ⅳ或Ⅳ-d₂₀(40nm,5%)/HB(10nm)/ ET:Liq(35nm,50%)/Liq(10nm)/Al(150nm)的OLED器件,并研究了它们的器件性能。结果表明：铱配合物Ⅳ-d₂₀表现出更优异的器件性能。电流密度为20mA/cm₂^时,铱配合物Ⅳ-d₂₀的器件发射波长为552nm,CIE 坐标为 (0.422,0.569),电流效率为 87.00cd/A,外量子效率(EQE)高达23.82%。     

Properties of polymer light‐emitting diodes coated on surface‐treated ITO/glass substrates

We fabricated blue polymer light‐emitting diodes (PLEDs) with indium tin oxide (ITO)/PEDOT : PSS/PVK/PFO‐poss/LiF/Al structures. All of the organic film layers were prepared by the spin‐coating method on plasma and heat‐treated ITO/glass substrates. The dependences of the optical and electrical properties of the PLEDs on the plasma and heat treatment of the ITO film and the introduction of poly(N‐vinylcarbazole) (PVK) layer were investigated. The AFM measurements indicated that the surface roughness of the ITO transparent film was improved by the plasma and heat treatment. In the emission spectra, the intensity of the excimer peaks of the PFO‐poss [polyhedral oligomeric silsesquioxane‐terminated poly(9,9‐dioctylfluorene)] emission layer were decreased for the PLED device with the PVK film layer compared with the one without the PVK layer. The maximum current density, luminance and current efficiency of the PLEDs were found to be about 470 mA/cm², 486 cd/m² at an input voltage of 12 V and 0.55 cd/A at 100 cd/m² in luminance, respectively. The color coordinates (CIE chart) of the blue PLEDs were in the range of x = 0.17 ～ 0.20, y = 0.13 ～ 0.16, and the peak emission spectrum was about 430 nm, showing a good blue color. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polylactide‐perylene derivative for blue biodegradable organic light‐emitting diodes

In this work we demonstrate, for the first time, the use of polylactic acid (PLA) as a biodegradable host matrix for the construction of the active emissive layer of organic light‐emitting diode (OLED) devices for potential use in bioelectronics. In this preliminary study, we report a robust synthesis of two fluorescent PLA derivatives, pyrene‐PLA ( AH10 ) and perylene‐PLA ( AH11 ). These materials were prepared by the ring opening polymerisation of l ‐lactide with hydroxyalkyl‐pyrene and hydroxyalkyl‐perylene derivatives using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene as catalyst. OLEDs were fabricated from these materials using a simple device architecture involving a solution‐processed single‐emitting layer in the configuration ITO/PEDOT:PSS/PVK:OXD‐7 (35%): AH10 or AH11 (20%)/TPBi/LiF/Al (ITO, indium tin oxide; PEDOT:PSS, poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid); PVK, poly(vinylcarbazole); OXD‐7, (1,3‐phenylene)‐bis‐[5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole]; TPBi, 2,2′,2″‐(1,3,5‐benzenetriyl)tris(1‐phenyl‐1H‐benzimidazole)). The turn‐on voltage for the perylene OLED at 10 cd m^–2 was around 6 V with a maximum brightness of 1200 cd m^–2 at 13 V. The corresponding external quantum efficiency and device current efficiency were 1.5% and 2.8 cd A^–1 respectively. In summary, this study provides proof of principle that OLEDs can be constructed from PLA, a readily available and renewable bio‐source. © 2020 The Authors. Polymer International published by John Wiley & Sons Ltd on behalf of Society of Industrial Chemistry.     

Efficient white polymer-light-emitting-diodes based on polyfluorene end-capped with yellowish-green fluorescent dye and blended with a red phosphorescent iridium complex

A novel series of blue and yellowish-green light-emitting single polymers were prepared by end-capping of low contents of 4-bromo-7H-benzo [de]naphtha[2′,3′:4,5]imidazo[2,1-a]isoquinolin-7-one (M1) into polyfluorene. Electroluminescence (EL) spectra of these polymers exhibit blue emission (λ_max = 430/460 nm) from the fluorene segments and yellowish-green emission (λ_max = 510/530 nm) from the M1 units. For the polymer (PFNAP-0.06) with the M1 unit content of 0.06 mol-%, its EL spectrum shows balanced intensities of blue emission and yellowish-green emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.25, 0.34). The maximum brightness of the device prepared from the polymer (PFNAP-0.06) is 6704 cd/m² at 10 V with a structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) [PEDOT:PSS]/PVK/emission layer/Ca/Ag. A new white polymer-light-emitting-diode (WPLED) can be developed from the single polymer (PFNAP-0.06) system blended with a red phosphorescent iridium complex [Bis(2-[2′-benzothienyl)-pyridinato-N,C^3′] iridium (acetylacetonate) (BtpIr)]. We were able to obtain a white-light-emission device by adjusting the molar ratio of BtpIr to PFNAP-0.06 with a structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) [PEDOT:PSS]/PVK/emission layer/Ca/Ag. The brightness in such a device configuration is 4030 cd/m² at 9 V with CIE coordinates of (0.32, 0.34).     

Green polymer-light-emitting-diodes based on polyfluorenes containing N-aryl-1,8-naphthalimide and 1,8-naphthoilene-arylimidazole derivatives as color tuner

A novel series of green light emitting single polymers were prepared by end-capping of N-aryl-1,8-naphthalimide and 1,8-naphthoilenearylimidazole derivatives into polyfluorene. The electroluminescence (EL) spectra of polymers (P1 ∼ P5) exhibit greenish-blue, bluish-green, pure green, and yellowish-green emission (λ_max = 465 nm, 490 nm, 500 nm, and 545 nm, respectively) from compounds (M1 ∼ M5). It was found that by the introduction of a small amount of compounds (M1 ∼ M5) (5 mol-%) into polyfluorene, the emission color can be tuned from the blue to green region. The color tuning was found to have gone through charge trapping and Förster energy transfer. The device of P4 emits pure green light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.20, 0.41), and exhibits a maximum brightness of 11500 cd/m² at 12 V with a structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid) [PEDOT:PSS]/PVK/emission layer/Ca/Ag. The device of P5 emits yellowish green light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.36, 0.56), and exhibits a maximum brightness of 6534 cd/m² at 17 V.     

New light-emitting hyperbranched polymers prepared from tribromoaryls and 9,9-dihexylfluorene-2,7-bis(trimethyleneborate)

Three new hyperbranched polymers (P1-P3) were prepared by copolymerization of tribromoaryl moieties (triphenylamine, carbazole and fluorene moieties) with 9,9-dihexylfluorene-2,7-bis(trimethyleneborate) from “A₂ + B₃” approach based on Suzuki polycondensation reaction. They are soluble in common organic solvents, and exhibit good thermal stable luminescence. Interestingly, unlike most of fluorene-containing polymeric materials, P3 emits strong green light due to its special structure. Double-layer devices with configurations ITO/PEDOT/Polymer (50 nm)/TPBI(50 nm)/LiF(0.5 nm)/Al(80 nm) were fabricated and emitted blue or green light, with maximum luminance in the range of 25-142 cd/m² and the current efficiency up to 0.18 cd/A.     

Effects of diamond-like carbon in TPD-Alq3 doped PVK organic light-emitting devices

Effects of an ultrathin (~ 1 nm) diamond-like carbon (DLC) layer in single-layer organic light-emitting devices (OLEDs) that consist of ITO/(TPD-Alq₃ doped PVK)/Al were investigated. DLC layers deposited by using Nd:YAG laser at laser wavelengths of 355 nm were high in sp³ content and resistivity (DLC_UV) while that of 1064 nm laser were lower in sp³ content and resistivity (DLC_IR), as characterized by Raman spectroscopy and resistivity measurements. Although emission were obtained for all the devices, only the device of ITO/DLC_UV/(TPD-Alq₃ doped PVK)/Al exhibited enhanced current density and brightness with lower turn-on voltage as compared to a standard device. Devices of ITO/DLC_IR/(TPD-Alq₃ doped PVK)/Al and ITO/(TPD-Alq₃ doped PVK)/DLC_UV/Al showed poor current and brightness characteristics but failed at higher applied voltage. The enhance performance of device with high resistivity/sp³ DLC film suggests the mechanisms of barrier reduction by sufficiently thin insulating layer which increase the probability of tunneling of carriers at ITO and PVK interface.     

Metallo-homopolymer and metallo-copolymers containing light-emitting poly(fluorene/ethynylene/(terpyridyl)zinc(II)) backbones and 1,3,4-oxadiazole (OXD) pendants

A series of novel metallo-polymers containing light-emitting poly(fluorene/ethynylene/(terpyridyl)zinc(II)) backbones and electron-transporting 1,3,4-oxadiazole (OXD) pendants (attached to the C-9 position of fluorene by long alkyl spacers) were synthesized by self-assembled reactions. The integrated ratios of ¹H NMR spectra reveal a facile result to distinguish the well-defined main-chain metallo-polymeric structures which were constructed by different monomer ligand systems (i.e. single, double, and triple monomer ligands with various pendants). Furthermore, UV-vis and photoluminescence (PL) spectral titration experiments were carried out to verify the metallo-polymeric structures by varying the molar ratios of zinc(II) ions to monomers. As a result, the enhancement of thermal stability (T_d) and quantum yields were introduced by the metallo-polymerization, and their physical properties were mainly affected by the nature of the pendants. The photophysical properties of these metallo-polymers exhibited blue PL emissions (around 418 nm) with quantum yields of 34-53% (in DMF). In contrast to metallo-polymers containing alkyl pendants, the quantum yields were greatly enhanced by introducing 1,3,4-OXD pendants but reduced by carbazole (CAZ) pendants. Moreover, electroluminescent (EL) devices with these light-emitting metallo-polymers as emitters showed green EL emissions (around 550 nm) with turn-on voltages of 6.0-6.5 V, maximum efficiencies of 1.05-1.35 cd A⁻¹ (at 100 mA/cm⁻²), and maximum luminances of 2313-3550 cd/m² (around 15 V), respectively.     

Novel white-light-emitting polyfluorenes with benzothiadiazole and Ir complex on the backbone

Novel white-emitting polyfluorenes were synthesized by mixing fluorescence and phosphorescence emission. Benzothiadiazole(BT) and iridium(III)bis(2-(1-naphthalene)pyridine-C^2′,N)-2,2,6,6-tetramethyl-3,5-heptanedione[(1-npy)₂Ir(tmd)] units were incorporated into polyfluorene backbone as green and red chromophores by Suzuki polycondensation. The device from PFG03-IrR07 shows a maximum luminous efficiency (LE) of 5.3 cd/A, a maximum luminance of 9900 cd/m² at a current density of 453 mA/cm² and a CIE coordinate of (0.32, 0.34) with the configuration: ITO/PEDOT:PSS/PVK/emissive layer/CsF/Al. Besides, the EL efficiencies decline slightly with increasing the current density. All emissions located very close to the equi-energy white point (0.33, 0.33) when applied voltage change from 9 to 14 V. Furthermore, the white emission of devices based on these materials shows very good color quality, with high color rendering index range between 84 and 89. Our results indicate that, by incorporation of singlet and triplet species into polymer backbone, the obtained white-emitting materials and devices are promising candidates for display and solid-state-lighting purpose.     

Blue‐light‐emitting poly(arylene ethynylenes) containing alternating sequences of biphenylene or fluorenediyl and p‐phenylene moieties linked through triple bonds

Two new poly(arylene ethynylenes) were synthesized by the reaction of 1,4‐diethynyl‐2.5‐dioctylbenzene either with 4,4′‐diiodo‐3,3′‐dimethyl‐1,1′‐biphenyl or 2,7‐diiodo‐9,9‐dioctylfluorene via the Sonogashira reaction, and their photoluminescence (PL) and electroluminescence (EL) properties were studied. The new poly(arylene ethynylenes) were poly[(3,3′‐dimethyl‐1,1′‐biphenyl‐4,4′‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEBE) and poly[(9,9‐dioctylfluorene‐2,7‐diyl)‐1,2‐ethynediyl‐(2,5‐dioctyl‐1,4‐phenylene)‐1,2‐ethynediyl] (PPEFE), both of which were blue‐light emitters. PPEBE not only emitted better blue light than PPEFE, but it also performed better in EL than the latter when the light‐emitting diode devices were constructed with the configuration indium–tin oxide/poly(3,4‐ethylenedioxythiophene) doped with poly(styrenesulfonic acid) (50 nm)/polymer (80 nm)/Ca:Al. The device constructed with PPEBE exhibited an external quantum efficiency of 0.29 cd/A and a maximum brightness of about 560 cd/m², with its EL spectrum showing emitting light maxima at λ = 445 and 472 nm. The device with PPEFE exhibited an efficiency of 0.10 cd/A and a maximum brightness of about 270 cd/m², with its EL spectrum showing an emitting light maximum at λ = 473 nm. Hole mobility (μ_h) and electron mobility (μ_e) of the polymers were determined by the time‐of‐flight method. Both polymers showed faster μ_h values. PPEBE revealed a μ_h of 2.0 × 10^?4 cm²/V·s at an electric field of 1.9 × 10⁵ V/cm and a μ_e of 7.0 × 10^?5 cm²/V·s at an electric field of 1.9 × 10⁵ V/cm. In contrast, the mobilities of the both carriers were slower for PPEFE, and its μ_h (8.0 × 10^?6 cm²/V·s at an electric field of 1.7 × 10⁶ V/cm) was 120 times its μ_e (6.5 × 10^?8 cm²/V·s at an electric field of 8.6 × 10⁵ V/cm). The much better balance in the carriers' mobilities appeared to be the major reason for the better device performance of PPEBE than PPEFE. Their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels were also a little different from each other. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 299–306, 2006