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.     

Screening structure-property correlations and device performance of Ir(III) complexes in multi-layer PhOLEDs

The structure-property correlations of a set of heteroleptic red- and green-emitting Ir(III) complexes with different temperature sensitivities and charge trapping capabilities are described, revealing superb performance in multi-layer phosphorescent organic light-emitting diodes (PhOLEDs) expressed by very high maximum luminous efficiencies up to 36.8 cd A(-1). Using 2-phenylpyridine and with 2-(naphthalen-1-yl)pyridine as the C^N ligand, the resulting red emitting complex featured a maximum luminous efficiency of 10.8 cd A(-1); one of the most excellent device performances within this class of red Ir(III) emitters.     

Effective shielding of triplet energy transfer to conjugated polymer by its dense side chains from phosphor dopant for highly efficient electrophosphorescence

To examine the quenching of a triplet exciton by low triplet energy (E(T)) polymer hosts with different chain configurations for high E(T) phosphor guests, the quenching rate constant measurements were carried out and analyzed by the standard Stern-Volmer equation. We found that an effective shielding of triplet energy transfer from a high E(T) phosphor guest to a low E(T) polymer host is possible upon introducing dense side chains to the polymer to block direct contact from the guest such that the possibility of Dexter energy transfer between them is reduced to a minimum. Together with energy level matching to allow charge trapping on the guest, high device efficiency can be achieved. The extent of shielding for the systems of phenylene-based conjugated structures from iridium complexes follows the sequence di-substituted (octoxyl chain) in the para position (dC8OPPP) is greater than monosubstituted (mC8OPPP) and the PPPs with longer side chains are much higher than a phenylene tetramer (P4) with two short methyl groups. Further, capping the dialkoxyl-susbstituents with a carbazole (Cz) moiety (CzPPP) provides enhanced extent of shielding. Excellent device efficiency of 30 cd/A (8.25%) for a green electrophosphorescent device can be achieved with CzPPP as a host, which is higher than that of dC8OPPP as host (15 cd/A). The efficiency is higher than those of high E(T) conjugated polymers, poly(3,6-carbazole) derivatives, as hosts (23 cd/A). This observation suggests a new route for molecular design of electroluminescent polymers as a host for a phosphorescent dopant.     

无间隔层结构的高效率荧光/磷光混合型白光有机发光二极管

采用磷光红光/荧光蓝光/磷光绿光无间隔层三发光层结构,制备出了高效率荧光/磷光混合型白光有机发光二极管(OLEDs),其中选取具有高荧光量子产率(PLQY)的荧光染料4P-NPD(双[N-(1-萘基)-N-苯基-氨基]四联苯)作为蓝光发射分子,以及常用的高效磷光染料Ir(MDQ)₂(acac)和Ir(ppy)₃(acac)分别作为红光和绿光的客体,通过混合和掺杂的方法制备了相应的发光层,实现了发光层中激子的有效利用和白光发射。 制备的白光器件最大电流效率和功率效率分别达到了27.1 cd/A和30.3 lm/W,当电压为6 V时,CIE色坐标为(0.33,0.41),显色指数CRI为70,色温CCT为5432 K。 在此基础上,设计制备了高色温的荧光/磷光混合型白光OLEDs,其色温(CCT)达到了7106 K。     

Investigating side chain mediated electroluminescence from carbazole-modified polyfluorene

In molecular design of electroluminescent (EL) conjugated polymers, introducing a charge transport moiety on a side chain is found to be a promising method for balancing electron and hole fluxes in EL devices without changing the emitting color if there is no interaction between moiety and main chain. In the case of grafting a carbazole (Cz) moiety (hole transporting) on blue emitting polyfluorene, a green emission appears with intensity comparable to the blue emission, which was attributed to a possible interaction between main chain and Cz as previously reported by us. Here, a detailed study of its EL mechanism was carried out by means of time-resolved EL with the assistance of molecular simulation and thermally stimulated current measurements; exploration of how main chain segments interact with the transport moiety was performed. We found the Cz groups in Cz100PF play multiple roles: they act as (1) hole transporter to improve hole injection, (2) hole trapping site for efficient electron-hole recombination to yield blue-emitting excitons, and (3) source of green emission from electroplex formed via electric field-mediated interaction of the Cz/Cz radical cation with an electron in the nearby PF backbone. In combination, these observations suggest that integrated consideration for both intramolecular and intermolecular interactions provides a new route of molecular design of efficient EL polymers.     

Functionality of peripheral side chain for enhanced performance of conjugated polymer—F8BT as an example

A series of F8BT‐based copolymers (PCFBTs) with functional peripheral side chains were designed and synthesized. The complementation of side chain with polymer backbone in electronic and optical properties was realized. Electron‐riched carbazole moieties on the peripheral side chains of fluorene unit significantly reduce the first oxidation potential and increase the highest occupied molecular orbital energy levels of PCFBTs. Increase of hole injection and transport ability was achieved in PCFBTs. Among them, PCFBT shows a maximum luminous efficiency of 0.7 cd/A and a turn‐on voltage of 3.0 V in the single‐layered device, which are better than F8BT without the carbazole moieties (0.1 cd/A, 3.8 V). The radios of fluorene and benzothiadiazole (BTz) unit in polymers were adjusted to balance the electron and hole transport, and PCFBT0.2 (BTz:fluorene = 2:8) exhibits 13 times higher maximum luminous efficiency (10.8 cd/A) than F8BT (0.8 cd/A) in a double‐layered device. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Investigation of spacer influences in phosphorescent‐emitting nonconjugated PLED systems

An assay was introduced to clarify influences on electroluminescent behavior for RGB‐colored phosphorescent terpolymers with N,N‐Di‐p‐tolyl‐aniline as hole‐transporting unit, 2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole (tert‐BuPBD) as electron‐transporting unit, and different iridium complexes in RGB‐colors as triplet emitting materials. All monomers were attached with spacer moieties to the “para” position of a polystyrene. Polymer light emitting diodes (PLEDs) were built to study the electro‐optical behavior of these materials. The gist was a remarkable influence of hexyl‐spacer units to the PLED performance. For all three colors only very restricted PLED performances were found. In comparison RGB‐terpolymers were synthesized with directly attached charge transport materials to the polymer backbone. For this directly linked systems efficiencies were 28 cd A^?1 @ 6 V (green), 4.9 cd A^?1 @ 5 V (red) and 4.3 cd A^?1 @ 6 V (bluish). In summary we assume that an improved charge percolation pathways regarding to the higher content of semiconducting molecules and an improved charge transfer to the phosphorescent dopand in the case of the copolymers without spacers are responsible for the better device performance comparing the copolymers with hexyl spacers. The approach of the directly connected charge transport materials at the nonconjugated styrene polymer backbone should be favored for further investigations, therefore. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 389–402, 2010     

Energy transfer and triplet exciton confinement in polymeric electrophosphorescent devices

Energy transfer and triplet exciton confinement in polymer/phosphorescent dopant systems have been investigated. Various combinations of host‐guest systems have been studied, consisting of two host polymers, poly(vinylcarbazole) (PVK) and poly[9,9‐bis(octyl)‐fluorene‐2,7‐diyl] (PF), blended with five different phosphorescent iridium complexes with different triplet energy levels. These combinations of hosts and dopants provide an ideal situation for studying the movement of triplet excitons between the host polymers and dopants. The excitons either can be confined at the dopant sites or can flow to the host polymers, subject to the relative position of the triplet energy levels of the material. For PF, because of its low triplet energy level, the exciton can flow back from the dopants to PF when the dopant has a higher triplet energy and subsequently quench the device efficiency. In contrast, efficient electrophosphorescence has been observed in doped PVK films because of the high triplet energy level of PVK. Better energy transfer from PVK to the dopants, as well as triplet exciton confinement on the dopants, leads to higher device performance than found in PF devices. Efficiencies as high as 16, 8.0, and 2.6 cd/A for green, yellow, and red emissions, respectively, can be achieved when PVK is selected as the host polymer. The results in this study show that the energy transfer and triplet exciton confinement have a pronounced influence on the device performance. In addition, this study also provides material design and selection rules for the efficient phosphorescent polymer light‐emitting diodes. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2681–2690, 2003     

High triplet energy polymer as host for electrophosphorescence with high efficiency

We report the conjugated polymer P(tBu-CBP) as a host with high triplet energy (E(T) 2.53 eV) and suitable HOMO (5.3 eV) and LUMO (2.04 eV) energy levels. Upon doping with green and red emission Ir-complexes, it gives devices with high luminous and external quantum efficiencies for green emission (23.7 cd/A, 6.57%) and for red emission (5.1 cd/A, 4.23%), respectively, and low turn-on voltage (3 V). For both devices, the efficiencies are higher than those of the corresponding devices with the same backbone P(3,6-Cz) as a host by a factor of 4, even though the latter has an E(T) (2.6 eV) slightly higher than that of the former. The results reflect that, in phosphorescent devices, the difference in E(T) between the host and guest is not the only factor that determines the device efficiency, and the present side group modification via the 9 position of carbazole also plays an important role, which allows a tuning of HOMO and LUMO levels to provide more balance in electron and hole fluxes and provides prevention from formation of excimer.     

Carbazole compounds as host materials for triplet emitters in organic light-emitting diodes: polymer hosts for high-efficiency light-emitting diodes

A carbazole homopolymer and carbazole copolymers based on 9,9'-dialkyl-[3,3']-bicarbazolyl, 2,5-diphenyl-[1,3,4]-oxadiazole and 9,9-bis(4-[3,7-dimethyloctyloxy]phenyl)fluorene were synthesized and their electrical and photophysical properties were characterized with respect to their application as host in phosphorescent polymer light-emitting diodes. It is shown that the triplet energy of a polymer depends on the specific connections between its building blocks. Without changing the composition of the polymer, its triplet energy can be increased from 2.3 to 2.6 eV by changing the way in which the different building blocks are coupled together. For poly(9-vinylcarbazole) (PVK), a carbazole polymer often used as host for high-energy triplet emitters in polymer light-emitting diodes, a large hole-injection barrier of about 1 eV exists due to the low-lying HOMO level of PVK. For all carbazole polymers presented here, the HOMO levels are much closer to the Fermi level of a commonly used anode such as ITO and/or a commonly used hole-injection layer such as PEDOT:PSS. This makes high current densities and consequently high luminance levels possible at moderate applied voltages in polymer light-emitting diodes. A double-layer polymer light-emitting diode is constructed comprising a PEDOT:PSS layer as hole-injection layer and a carbazole-oxadiazole copolymer doped with a green triplet emitter as emissive layer that shows an efficacy of 23 cd/A independent of current density and light output.     

Efficient π‐conjugated interrupted host polymer by metal‐free polymerization for blue/green phosphorescent light‐emitting diodes

A new aromatic host polymer poly{[1,4‐bis(9‐decylcarbazole‐3‐yl)‐2,3,5,6‐tetrafluorobenzene‐3,3′‐diyl]‐alt‐[N‐methylisatin‐2‐one‐3,3‐diyl]} (PICzFB) containing carbazole–tetrafluorinebeneze–carbazole moiety in the π‐conjugated interrupted polymer backbone was synthesized by superacid‐catalyzed metal‐free polyhydroxyalkylation. The resulted copolymer PICzFB showed a comparatively wide band gap up to 3.32 eV and high triplet energy (E_T) of 2.73 eV due to confined conjugation by the δ? C bond interrupted polymer backbone. Blue and green light‐emitting devices with PICzFB as host, FIrpic and Ir(mppy)₃ as phosphorescent dopants showed the maximum luminous efficiencies of 5.0 and 27.6 cd/A, respectively. The results suggested that the strategy of incorporating bipolar unit into the π‐conjugated interrupted polymer backbone can be a promising approach to obtain host polymer with high triplet level for solution‐processed blue and green phosphorescent polymer light‐emitting diodes. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1037–1046     

White and Red Organic Light Emitting Materials

Derivatives of 2,3-(1,4-dialkoxyaceno)norbornadiene underwent ring-opening metathesis polymerization (ROMP) upon the catalysis of a ruthenium complex to afford the corresponding polymers. The polymeric materials containing anthracene chromophores emit white electro-luminescence, which can be fabricated into light-emitting diodes (LED). The broad emission band is composed of a blue emission from anthracene and a red emission from aggregates. A single layer device, ITO/polymer/Ca/Al, can be turned on at 7V and exhibits maximum intensity 427 cd/m2 at 15 V. A double layer device, ITO/polymer/TPBI/Mg:Ag (TPBI = (2,2′,2"-(1,3,5-benzenetriyl)-tris(1-phenyl-1H-benzimidazole)) displayed blue light with turn-on voltage 6 V and maximal intensity 930 cd/m2 at 15 V.Derivatives of bisindolylmaleimide were found to form amorphous solid films which exhibit intensive red luminescence. The property of forming glasses can be ascribed to the nonplanar geometry of these molecules. LED devices were fabricated by a layer of pure dye sandwiched between two charge transporting films. The yellow emission spectrum of the devices utilizing Alq (tris(8-hydoxyquinolinato)aluminum) contains a green component from Alq. Pure red emissions can be achieved by replacing Alq with TPBI. Typical devices can be turned on at ～3 V with maximal intensity 2000 cd/m2. White color devices are under current investigation, in which the green Alq layer is replaced by its blue derivative (bis(2-methyl-8-hydoxyquinolinato)(phenolato)aluminum).     

以5-取代-8-羟基喹啉和2-苯基吡啶为配体的金属铱配合物的合成、表征及光致、电致发光性质

本文通过在8-羟基喹啉的5位上引入氨基和取代的苯基,合成了系列二-[2-苯基吡啶（C^N）][5-取代-8-羟基喹啉（N^O）]铱（Ⅲ）配合物（（C^N）2IrQ）.这里CN代表2-苯基吡啶,Q代表5-取代-8-羟基喹啉.通过1HNMR、13CNMR、MS、元素分析、单晶X-衍射等对配合物的化学和晶体结构进行了表征.利用循环伏安、UV-Vis、光致和电致发光光谱等对它们的光物理性质进行了表征.热重分析表明苯环上的取代基对配合物热稳定性有很大影响.常温下,几种5-取代苯基喹啉铱配合物的溶液和固体产生红色磷光发射,光致发光（PL）光谱在666和687nm附近出现两个强度基本相等的发射峰.配合物的发光性质主要受喹啉环和5位苯基的影响,苯环上的取代基团对配合物的发光性质影响不大.而5-氨基喹啉铱配合物PL光谱的最大发射峰在550nm,其PL光谱主要受2-苯基吡啶的影响.将配合物二-[2-苯基吡啶（C^N）][5-（4-甲氧基苯基）-8-羟基喹啉（N^O）]铱（Ⅲ）（7b）掺杂在聚2,7-（9,9-二辛基）芴（PFO）和30%（质量分数）的2-对叔丁基苯基-5-对联苯基-1,3,4-口恶二唑（PBD）的主体材料中,制备了聚合物发光器件（OLED）,器件电致发光（EL）光谱的发射峰在672nm处,18V时最大亮度为350cd/m2,在电压14V时CIE色坐标值为（0.61,0.33）,是一红光OLED器件.     

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).     

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%.     

Hole‐transporting host‐polymer series consisting of triphenylamine basic structures for phosphorescent polymer light‐emitting diodes

A series of novel styrene derived monomers with triphenylamine‐based units, and their polymers have been synthesized and compared with the well‐known structure of polymer of N,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine with respect to their hole‐transporting behavior in phosphorescent polymer light‐emitting diodes (PLEDs). A vinyltriphenylamine structure was selected as a basic unit, functionalized at the para positions with the following side groups: diphenylamine, 3‐methylphenyl‐aniline, 1‐ and 2‐naphthylamine, carbazole, and phenothiazine. The polymers are used in PLEDs as host polymers for blend systems with the following device configuration: glass/indium–tin–oxide/PEDOT:PSS/polymer‐blend/CsF/Ca/Ag. In addition to the hole‐transporting host polymer, the polymer blend includes a phosphorescent dopant [Ir(Me‐ppy)₃] and an electron‐transporting molecule (2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole). We demonstrate that two polymers are excellent hole‐transporting matrix materials for these blend systems because of their good overall electroluminescent performances and their comparatively high glass transition temperatures. For the carbazole‐substituted polymer (T_g = 246 °C), a luminous efficiency of 35 cd A^?1 and a brightness of 6700 cd m^?2 at 10 V is accessible. The phenothiazine‐functionalized polymer (T_g = 220 °C) shows nearly the same outstanding PLED behavior. Hence, both these polymers outperform the well‐known polymer of N,N′‐bis(3‐methylphenyl)‐N,N′‐diphenylbenzidine, showing only a luminous efficiency of 7.9 cd A^?1 and a brightness of 2500 cd m^?2 (10 V). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3417–3430, 2010     

Simple Bipolar Hosts with High Glass Transition Temperatures Based on 1,8‐Disubstituted Carbazole for Efficient Blue and Green Electrophosphorescent Devices with “Ideal” Turn‐on Voltage

Two hybrids based on 1,8‐disubstituted carbazole, 1,8‐OXDCz and 1,8‐mBICz , have been designed and synthesized through a facile process. The incorporation of oxadiazole or N‐phenylbenzimidazole moieties at the 1,8‐positions of carbazole greatly improves its morphological stability, giving glass transition temperatures (T_g) as high as 138 and 154 °C, respectively. Blue phosphorescent organic light‐emitting devices (PhOLEDs) with 1,8‐mBICz exhibit almost the same performance as a similarly structured device based on the mCP host, and green PhOLEDs employing the new host material 1,8‐OXDCz exhibit an ideal turn‐on voltage (2.5 V at 1.58 cd m^?2), a maximum current efficiency (η_c,max) of 73.9 cd A^?1, and a power efficiency (η_p,max) of 89.7 lm W^?1. These results are among the best performances of [Ir(ppy)₃]‐based devices with simple device configurations.     

Synthesis and characterization of novel germanium‐containing poly(p‐phenylenevinylene) derivatives

Novel blue‐emitting germanium‐containing poly(p‐phenylenevinylene) (PPV) derivatives with well‐defined conjugation lengths were synthesized via Wittig‐condensation polymerizations. The polymers can be color‐tuned by the introduction of various chromophores into the PPV‐based polymer backbones. The photoluminescence (PL) spectra of the polymers, GePVK (containing carbazole moieties), GeMEH (containing dialkoxybenzene moieties), and GePTH (containing phenothiazine moieties), were found to exhibit blue, greenish blue, and green emissions, respectively. GePTH produces more red‐shifted emission than GeMEH and GEPVK, resulting in green emission, and the solution and solid state PL spectra of GePVK consist of almost blue emission. The electroluminescence spectra of GeMEH and GePTH contain yellowy green and yellow colors, respectively. Interestingly, GePVK exhibits white emission with CIE coordinates of (0.33, 0.37) due to electroplex emission in the light‐emitting diodes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 979–988, 2008     

含稀土铕络合物的三元共聚物的光电性质

合成了可平衡电荷(空穴与电子)传输的三功能合一的稀土铕发光材料,将几种稀土铕络合物单体与乙烯基咔唑、甲基丙烯酸甲酯共聚制得含咔唑和稀土铕络合物的空穴传输层发光层电子传输层(HTLEMLETL)三功能合一的聚合物,并研究它们的电化学及电致发光性能.电化学分析表明这类三元共聚物兼有氧化性和还原性,氧化电位及还原电位分别为0.75V和-1.8V左右,可见这类材料同时具有空穴传输和电子传输功能.从测定的电致发光谱看,AlQ3、TPD及咔唑基等发光单元在器件中没有共发光,而是起电荷传输作用,以这些材料制作的电致发光器件所发的红光纯度都比较高.     

一步法合成螺双芴及螺氧杂蒽衍生物及其在有机发光二极管中的应用：性能增强及相关的光学现象关

以芴为原料,以钯为催化剂一步合成了2-(9-苯基芴基)-9,9′螺二芴(PF-SBF)。以PF-SBF作为有机发光二极管的发光及主体材料(FIrpic为磷光客体)时,观察到了不同于PF-SBF及FIrpic发光的红光带。这分别源于PF-SBF分子间的聚集和发光层/传输层诱导的激基复合物。通过选择合适的空穴和电子传输层,有效抑制了激基复合物的发光。同时,PF-SBF和TAPC双主体的结构不仅实现了纯FIrpic和Ir(ppy)3蓝光和绿光,还大幅提升了器件性能。蓝光、绿光器件的最大电流效率和最大亮度分达到16.7、50.5 cd·A^-1和7857 cd·m^-2(11 V)、23390 cd·m^-2(8 V)。另外,除了PF-SBF,利用相似的合成方法,我们也合成了2-(9-苯基芴基)-9,9′螺芴氧杂蒽(PF-SFX),其较大的三线态能级(2.8 eV)较PF-SBF更适合做蓝光主体。以TAPC和PFSFX为双主体的器件最大电流效率提升到了22.6 cd·A^-1。所有实验结果均表明,PF-SBF和PF-SFX是构建高效绿光/蓝光磷光主体材料的有效结构单元。