微波辐射法合成喹喔啉铱（Ⅲ）配合物及其发光性质

采用微波辐射加热方法,将2,3-二苯基喹喔啉（DPQ）与水合三氯化铱（IrCl3•H2O）反应,合成了一种新型三环喹喔啉铱配合物[Ir(DPQ)3],通过元素分析,1H NMR和质谱方法对配合物结构进行了表征,并初步研究了配合物的吸收光谱和荧光光谱。结果表明,配合物Ir(DPQ)3在387和458nm处存在单线态1MLCT（金属到配体的电荷跃迁）和三线态3MLCT的吸收;在634nm 处有较强的金属配合物三线态的磷光发射。     

一种新型红色三线态喹喔啉铱(Ⅲ)配合物的合成及发光性质

利用2,3-二苯基喹喔啉和水合三氯化铱(IrCl₃?H₂O)反应, 合成了一种新型喹喔啉铱的配合物[Ir(DPQ)₂(acac)], 通过元素分析, ¹H NMR和HRMS对配合物结构进行了表征, 结果显示得到的是目标化合物. 利用紫外光谱和荧光光谱对配合物的吸收光谱和光致发光光谱进行了研究. 利用该材料作为磷光材料制备了结构为[ITO/NPB(30 nm)/NPB∶7% Ir(DPQ)₂(acac)(25 nm)/PBD (10 nm)/Alq₃ (30 nm)/Mg∶Ag (10∶1)(120 nm)/Ag(10 nm)] 的电致发光器件, 研究了其电致发光光谱. 结果表明, 配合物[Ir(DPQ)₂(acac)]在476和625 nm处存在单重态¹MLCT(金属到配体的电荷跃迁)和三重态³MLCT的吸收峰; 发光光谱结果显示, 在660 nm处有较强的金属配合物三重态的磷光发射; 电致发光光谱显示, 该器件的启动电压是4.25 V, 器件的最大亮度为4910 cd/m², 外量子效率为5.14%, 器件的流明效率为1.12 lm/W, 是一种新型红色磷光材料.     

Phosphorescent Cationic Iridium (III) Complexes with 1,3,4-Oxadiazole Cyclometalating Ligands:Solvent-Dependent Excited-State Dynamics

To elucidate the nature of low-lying triplet states and the effect of ligand modifications on the excited-state properties of functional cationic iridium complexes,the solventdependent excited-state dynamics of two phosphorescent cationic iridium (III) complexes,namely[Ir (dph-oxd)₂(bpy)]PF₆( 1 ) and[Ir (dph-oxd)₂(pzpy)]PF₆( 2 ),were investigated by femtosecond and nanosecond transient absorption spectroscopy.Upon photoexcitation to the metal-to-ligand charge-transfer (MLCT) states,the excited-state dynamics shows a rapid process (τ=0.7-3 ps) for the formation of solvent stabilized ³MLCT states,which significantly depends on the solvent polarity for both 1 and 2 .Sequentially,a relatively slow process assigned to the vibrational cooling/geometrical relaxation and a long-lived phosphorescent emissive state is identified.Due to the different excited-state electronic structures regulated by ancillary ligands,the solvation-induced stabilization of the ³MLCT state in 1 is faster than that in 2 .The present results provide a better sight of excited-state relaxation dynamics of ligand-related iridium (III) complexes and solvation effects on triplet manifolds.     

Hybrid White-Light-Emitting Electrochemical Cells Based on a Blue Cationic Iridium(III) Complex and Red Quantum Dots

Solid-state white light-emitting electrochemical cells (LECs) show promising advantages of simple solution fabrication processes, low operation voltage, and compatibility with air-stable cathode metals, which are required for lighting applications. To date, white LECs based on ionic transition metal complexes (iTMCs) have shown higher device efficiencies than white LECs employing other types of materials. However, lower emission efficiencies of red iTMCs limit further improvement in device performance. As an alternative, efficient red CdZnSeS/ZnS core/shell quantum dots were integrated with a blue iTMC to form a hybrid white LEC in this work. By achieving good carrier balance in an appropriate device architecture, a peak external quantum efficiency and power efficiency of 11.2 % and 15.1 lm W⁻¹, respectively, were reached. Such device efficiency is indeed higher than those of the reported white LECs based on host–guest iTMCs. Time- and voltage-dependent electroluminescence (EL) characteristics of the hybrid white LECs were studied by means of the temporal evolution of the emission-zone position extracted by fitting the simulated and measured EL spectra. The working principle of the hybrid white LECs was clarified, and the high device efficiency makes potential new white-emitting devices suitable for solid-state lighting technology possible.     

Tuning the Photophysical and Excited State Properties of Phosphorescent Iridium(III) Complexes by Polycyclic Unit Substitution

Two novel N-embedded polycyclic units functionalized phosphorescent iridium(III) complexes ( Ir-1 and Ir-2 ) with substituents in different positions have been prepared. Complex Ir-1 bearing the substituent at the 3-position shows a distinct blue shift single-peak emission (524 nm) with a higher luminescence efficiency (Φ_PL=42 %) and shorter emission lifetime (τ=282 ns) by comparison with 4-position substitution based complex Ir-2 (Φ_PL=23 %, τ=562 ns), which exhibits a dual-peak emission (564 nm and 602 nm), and phosphorescence color can be tuned from green to yellow. In addition, DFT calculations demonstrate that unusual ligand-to-metal charge transfer (³LMCT) excited state property can be found in Ir-2 , which is in contrast to metal-to-ligand charge transfer (³MLCT) excited state character in Ir-1 . This result can be attribute to strong electron-donating character and 4-position substitution effect of the unit.     

稠杂环化合物在红色磷光铱配合物中的应用

在过去的几十年里, 有机发光二极管(OLED)由于潜在的优势, 在全彩显示领域引起了高度重视. 电致磷光材料因其优异的发光性能, 引起了人们广泛关注. 对于实际应用的平板显示器, 蓝、绿、红三基色是必不可少的. 相对于高效的绿光材料, 红光磷光材料仍然存在色纯度差、效率低和亮度不足等问题, 因此设计合适的红光材料成为具有挑战性的问题. 稠杂环化合物因发光量子效率高、发光颜色可调、平衡电荷注入及迁移等优越性能而广泛应用于红色磷光铱配合物. 本文综述了近几年稠杂环化合物在小分子、树枝状及高分子红色磷光铱配合物中的应用, 阐述了铱配合物分子结构对材料光电性质及器件性能的影响, 最后展望了稠杂环化合物在红光磷光材料中的应用前景.     

基于苯基修饰策略的新型可溶液加工红光铱配合物的设计、合成及电致发光性能研究

利用向环金属配体的C-Ir键的对位进行苯基取代这一结构修饰策略,成功合成了两种新型铱（III）配合物（3PhNbt）₂Ir（acac）和（3OMePhNbt）₂Ir（acac）.相较其橙光发射的母体化合物（Nbt）₂Ir（acac）,两个目标化合物的抗结晶性、非晶态热稳定性及溶解性均有显著提高,其磷光发射带也发生了5~10 nm的红移.以（3PhNbt）₂Ir（acac）和（3OMePhNbt）₂Ir（acac）为发光客体材料所制备的单层溶液加工电致红光器件,其最大发光亮度分别为1830 cd·m^-2和6630 cd·m^-2,最大电流效率分别为2.4 cd·A^-1和8.7 cd·A^-1,CIE1931色坐标分别为（0.61,0.39）和（0.62,0.38）.相比之下,以母体化合物（Nbt）₂Ir（acac）为发光客体材料所制备的参比器件,其最大发光亮度则为1620 cd·m^-2,最大电流效率仅为1.5 cd·A^-1,CIE1931色坐标为（0.59,0.41）.上述研究结果表明：向C-Ir键对位进行苯基修饰可以在提高铱（III）配合物的可溶液加工性能的同时,获得更为红移的电致发光波长,是一种简单而有效的红光铱（III）配合物的分子设计策略.     

Unveiling Photodeactivation Pathways for a New Iridium(III) Cyclometalated Complex

We report the synthesis and characterization of a neutral heteroleptic Ir^III complex bearing 6‐fluoro‐2‐phenylbenzo[d]thiazole as cyclometalating ligand and (Z)‐6‐(9H‐carbazol‐9‐yl)‐5‐hydroxy‐2,2‐dimethylhex‐4‐en‐3‐one as ancillary ligand. The photodeactivation mechanisms have been elucidated through extensive density functional theory (DFT) calculations. The active role of metal‐centered (³MC) triplet excited states in the nonradiative deactivation pathways is, for first time, confirmed in such complexes.     

一种红光铱配合物的合成和电致发光性能

以1-(4-三氟甲基苯基)异喹啉(tfmpiq)为主配体,二(二(4-三氟甲基苯基)膦酰)胺(tfmtpip)为辅助配体,成功合成了Ir髥配合物Ir(tfmpiq)2(tfmtpip),并得到了配合物的晶体结构。配合物Ir(tfmpiq)2(tfmtpip)的分解温度为373℃,具有良好的热稳定性。Ir(tfmpiq)2(tfmtpip)的发射光谱主要是MLCT发射,峰位置为613 nm,量子效率为3.7%,HOMO和LUMO轨道能级分别为-5.62和-3.54 e V。基于Ir(tfmpiq)2(tfmtpip)的器件ITO/TAPC(40 nm)/Ir(tfmpiq)2(tfmtpip)(x%)∶mCP(20 nm)/TmPyPB(40 nm)/LiF(1 nm)/Al(100 nm),当掺杂浓度为4%(w/w)时,器件达到最大功率效率和电流效率分别为5.73 lm·W-1和7.13 cd·A-1,而且器件在12.8 V的驱动电压下达到亮度10 542 cd·m-2。     

含螺环位阻铱(III)配合物的共轭结构调控及其电致发光性能研究

基于螺[芴-9,9'-氧杂蒽]的位阻结构,在其芴端连接苯并噻唑构成共轭扩展的环金属配体,并成功合成了相应的均配、面式构型铱（III）配合物fac-Ir（SFXbtz）₃.配合物的最强发射峰位于587 nm,在635 nm处伴有肩峰发射;其在溶液中的磷光寿命为316 ns,光致发光量子产率达到64.7%.以fac-Ir（SFXbtz）₃为发射材料,在高掺杂浓度下分别制备了橙光电致发光器件及与蓝光材料FIrpic（双（4,6-二氟苯基吡啶-N,C²）吡啶甲酰合铱）组合的二元白光器件.以CBP（4,4'-二（9-咔唑）联苯）为主体材料的橙光器件最高电流效率和功率效率为10.8 cd·A^-1和8.4 lm·W^-1,最大亮度为7217 cd·m^-2.二元白光器件最高电流效率和功率效率为11.6 cd·A^-1和8.0 lm·W^-1,最大亮度为8763 cd·m^-2,在3~9 V操作电压下CIE1931色坐标稳定.结果表明：协同利用螺环芳烃的共轭结构和位阻结构优势,是获得低成本、本征光电性质良好及可高浓度掺杂的磷光铱（III）配合物的便捷方法.     

Synthesis,One‐ and Two‐Photon Photophysical and Excited‐State Properties,and Sensing Application of a New Phosphorescent Dinuclear Cationic Iridium(III) Complex

A new phosphorescent dinuclear cationic iridium(III) complex ( Ir1 ) with a donor–acceptor–π‐bridge–acceptor–donor (D? A? π? A? D)‐conjugated oligomer ( L1 ) as a N^N ligand and a triarylboron compound as a C^N ligand has been synthesized. The photophysical and excited‐state properties of Ir1 and L1 were investigated by UV/Vis absorption spectroscopy, photoluminescence spectroscopy, and molecular‐orbital calculations, and they were compared with those of the mononuclear iridium(III) complex [Ir(Bpq)₂(bpy)]⁺PF₆^? ( Ir0 ). Compared with Ir0 , complex Ir1 shows a more‐intense optical‐absorption capability, especially in the visible‐light region. For example, complex Ir1 shows an intense absorption band that is centered at λ=448 nm with a molar extinction coefficient (ε) of about 10⁴, which is rarely observed for iridium(III) complexes. Complex Ir1 displays highly efficient orange–red phosphorescent emission with an emission wavelength of 606 nm and a quantum efficiency of 0.13 at room temperature. We also investigated the two‐photon‐absorption properties of complexes Ir0 , Ir1 , and L1 . The free ligand ( L1 ) has a relatively small two‐photon absorption cross‐section (δ_max=195 GM), but, when complexed with iridium(III) to afford dinuclear complex Ir1 , it exhibits a higher two‐photon‐absorption cross‐section than ligand L1 in the near‐infrared region and an intense two‐photon‐excited phosphorescent emission. The maximum two‐photon‐absorption cross‐section of Ir1 is 481 GM, which is also significantly larger than that of Ir0 . In addition, because the strong B? F interaction between the dimesitylboryl groups and F^? ions interrupts the extended π‐conjugation, complex Ir1 can be used as an excellent one‐ and two‐photon‐excited “ON–OFF” phosphorescent probe for F^? ions.     

High Order in a Self‐Assembled Iridium(III) Complex Gelator Towards Nanostructured IrO2 Thin Films

The preparation and characterization of a new metallogelator based on the Ir^III discrete cyclometalated complex [(ppy)₂Ir(bpy)](CH₃CH₂OCH₂CO₂) are reported, where H(ppy) is 2‐phenylpiridine and bpy is 2,2′‐bipyridine, which is used as an ancillary ligand. The compound is able to self‐assemble in water in a range of concentrations between 3 % and 6 % w/w, creating a luminescent ordered supramolecular gel. The gel and xerogel architectures were investigated through polarized optical microscopy (POM), SEM and TEM microscopies coupled with powder X‐ray diffraction. The gel supramolecular organization is characterized by columnar tetragonal strands, already present at high dilution conditions, of cations surrounded by counteranions. These strands, in turn, are self‐assembled in an oblique columnar cell upon gelification. The xerogel thin films obtained upon complete dehydration maintained the gel supramolecular order and can be used as a precursor for the preparation of nanostructured IrO₂ thin films.     

Dual-emissive Iridium(III) Complexes as Phosphorescent Probes with Orthogonal Responses to Analyte Binding and Oxygen Quenching

Phosphorescent probes often show sensitive response toward analytes at a specific wavelength. However, oxygen quenching usually occurs at the same wavelength and thus hinders the accurate detection of analytes. In this study, we have developed dual-emissive iridium(III) complexes that exhibit phosphorescence responses to copper(II) ions at a wavelength distinct from that where oxygen quenching occurs. The complexes displayed colorimetric phosphorescence response in aqueous solutions under different copper(II) and oxygen conditions. In cellular imaging, variation in oxygen concentration over a large range from 5 % to 80 % can modulate the intensity and lifetime of green phosphorescence without affecting the response of red phosphorescence toward intracellular copper(II) ions.     

Copolymers Containing Phosphorescent Iridium(III) Complexes Obtained by Free and Controlled Radical Polymerization Techniques

A methacrylate‐functionalized phosphorescent Ir(III)‐complex has been synthesized, characterized, and applied as a monomer in radical copolymerizations. Together with methyl methacrylate, the complex has been copolymerized under free radical polymerization conditions. Aiming for host‐guest‐systems, applicable e.g. in organic light emitting devices (OLEDs), the complex was further copolymerized with a methacrylate‐functionalized carbazole derivative using the atom transfer radical polymerization technique. Applying gel permeation chromatography, in combination with a photodiode array detector, could clearly prove the formation of the copolymers. The optical properties of the photoactive monomers as well as the copolymers were investigated by absorption and emission spectroscopy (in solution). For the carbazole‐copolymer, the emission originates almost exclusively from the complex. This provides evidence of an efficient intrachain energy transfer, which makes the system an interesting candidate for potential OLED applications.

     

Synthesis,Structures and Photophysical Properties of Cationic Cyclometalated Iridium(III) Complexes Bearing N-Phenylcarbazole Group

Four cationic cyclometalated Ir^III complexes [(MeOPCz)₂Ir(bpy)]PF₆ ( 3 ), [(MeOPCz)₂Ir(dtb-bpy)]PF₆ ( 4 ), [(TFPCz)₂Ir(bpy)]PF₆ ( 5 ), and [(TFPCz)₂Ir(dtb-bpy)]PF₆ ( 6 ) were successfully synthesized using two new cyclometalated ligands 9-phenyl-3-(4-methoxypyridin-2-yl)-9H-carbazole (MeOPCz) 1 and 9-phenyl-3-(4-trifluoromethylpyridin-2-yl)-9H-carbazole (TFPCz) 2 in combination with 2,2'-bipyridine (bpy) and 4,4'-di-tert-butyl-2,2'-bipyridine (dtb-bpy) as ancillary ligands. These complexes adopt the distorted octahedral configuration, and the complexes 5 and 6 crystallize in the centrosymmetric space group C2/c. Emission wavelength of these complexes can be tuned from 583 nm to 628 nm by the substituents (methoxy, trifluoromethyl and tert-butyl groups) in ligands. All of these complexes show relatively high emission efficiencies (0.28–0.41) and short lifetimes (0.242–0.461 μs).     

红色磷光喹喔啉铂(II)配合物及其有机电致发光器件的制备

利用2,3-二苯基喹喔啉和氯亚铂酸钾(K2PtCl4)反应, 合成了一种新型喹喔啉铂的配合物(DPQ)Pt(acac), 通过元素分析, 1H NMR测定对配合物结构进行了表征, 结果显示得到的是目标化合物. 利用紫外光谱和荧光光谱对配合物进行了研究. 利用该材料作为磷光染料制备了结构为ITO/NPB (21 nm) /NPB∶7%(DPQ)Pt(acac) (17.5 nm) /BCP (7 nm)/ Alq3 (21 nm)/ Mg∶Ag(10∶1)(120 nm)/Ag(10 nm)的有机电致发光器件(OLED). 结果表明, 该配合物在442和485 nm处存在单重态1MLCT(金属到配体的电荷跃迁)和三重态3MLCT的吸收峰; 在632 nm 处有较强的金属配合物三重态的磷光发射; 该器件的启动电压是5.0 V, 器件的最大亮度为1516 cd·m-2, 外量子效率为0.66%, 流明效率为0.26 lm·W-1, 是一种红色磷光材料.     

Near‐IR Phosphorescent Ruthenium(II) and Iridium(III) Perylene Bisimide Metal Complexes

The phosphorescence emission of perylene bisimide derivatives has been rarely reported. Two novel ruthenium(II) and iridium(III) complexes of an azabenz‐annulated perylene bisimide (ab‐PBI), [Ru(bpy)₂(ab‐PBI)][PF₆]₂ 1 and [Cp*Ir(ab‐PBI)Cl]PF₆ 2 are now presented that both show NIR phosphorescence between 750–1000 nm in solution at room temperature. For an NIR emitter, the ruthenium complex 1 displays an unusually high quantum yield (Φ_p) of 11 % with a lifetime (τ_p) of 4.2 μs, while iridium complex 2 exhibits Φ_p<1 % and τ_p=33 μs. 1 and 2 are the first PBI‐metal complexes in which the spin–orbit coupling is strong enough to facilitate not only the S_n→T_n intersystem crossing of the PBI dye, but also the radiative T₁→S₀ transition, that is, phosphorescence.     

红色磷光喹喔啉铂(II)配合物及其有机电致发光器件的制备

利用2,3-二苯基喹喔啉和氯亚铂酸钾(K2PtCl4)反应,合成了一种新型喹喔啉铂的配合物(DPQ)Pt(acac),通过元素分析,1HNMR测定对配合物结构进行了表征,结果显示得到的是目标化合物.利用紫外光谱和荧光光谱对配合物进行了研究.利用该材料作为磷光染料制备了结构为ITO/NPB(21nm)/NPB∶7%(DPQ)Pt(acac)(17.5nm)/BCP(7nm)/Alq3(21nm)/Mg∶Ag(10∶1)(120nm)/Ag(10nm)的有机电致发光器件(OLED).结果表明,该配合物在442和485nm处存在单重态1MLCT(金属到配体的电荷跃迁)和三重态3MLCT的吸收峰;在632nm处有较强的金属配合物三重态的磷光发射;该器件的启动电压是5.0V,器件的最大亮度为1516cd·m-2,外量子效率为0.66%,流明效率为0.26lm·W-1,是一种红色磷光材料.