蓝光铱配合物的合成、结构表征及光物理性能测试

在碱性条件下,以铱的氯桥二聚体(dfppy)2Ir(μ-Cl2)Ir(dfppy)2和乙酰丙酮反应合成出高效磷光材料二[2-(2,4-二氟苯基)吡啶-C2,N'](乙酰丙酮)合铱(III)(Ir(dfppy)2(acac))。用核磁共振谱(1H NMR、13C NMR)、红外光谱和单晶X射线衍射等表征手段确定了分子结构,用高效液相色谱法测定了纯度,用光致发光光谱测试了光物理性能。结果表明,合成的配合物组成及结构与实际一致,Ir(dfppy)2(acac)为电中性八面体配合物,Ir-O、Ir-C、Ir-N键的平均长度分别为0.2160(14)、0.1998(11)、0.2030(15)nm,在484 nm处出现了较强的蓝光发射。方法的合成产率大于90%,纯度99.70%,适于批量制备。     

铱磷光配合物Ir(dfppy)2(phbudio)的合成及表征

以氯桥二聚体[Ir(dfppy)2(μ-Cl2)]2、1-苯基-1,3-丁二酮为原料合成了一种铱磷光配合物Ir(dfppy)2(phbudio),产率86.0%,并通过元素分析、核磁共振谱、质谱和红外光谱表征确认了目标产物的化学结构。通过紫外-可见吸收以及荧光光谱对其光物理性质进行测试,其常温最大发射位于522 nm处,显示发射强烈的绿光,初步推测该铱磷光配合物发射可能来自金属铱到环金属配体和辅助配体的电荷转移(MLCT)跃迁。     

一种中性铱磷光配合物的合成及表征

合成了一种含有苯基吡啶单元的中性铱磷光配合物Ir(dfppy)2(fubudio) (dfppy:2,4-二氟苯基吡啶;fubudio:1-(2-糠酰)-1,3-丁二酮)。通过元素分析、核磁共振谱(¹H-NMR和¹³C-NMR)、质谱和红外光谱等表征手段确认了它的组成和化学结构。并采用紫外-可见吸收光谱和光致发光光谱对其光物理性质进行测试,常温下,其最大发射位于569 nm处,显示黄绿光发射。     

一种联吡啶类铱配合物的合成及光物理性能测试

以2-(2,4-二氟苯基)吡啶为主配体,2,2''-联吡啶为辅助配体,设计合成出了一种联吡啶铱配合物[Ir(dfppy)2(bpy)]PF6 (dfppy = 2-(2,4-二氟苯基)吡啶,bpy = 2,2''-联吡啶)。通过元素分析、质谱、核磁共振谱、红外光谱和X射线单晶测试表征了配合物的化学结构,通过光致发光光谱和紫外可见光谱研究了配合物的光物理性能。结果表明,配合物的最大发射波长为515 nm,发光颜色为绿光。     

两种嘧啶基噻吩类磷光铱配合物的合成及表征

以2-嘧啶基噻吩(pymbt,L1)和2-嘧啶基苯并噻吩(pymbtp,L2)作为环金属化主配体,二(二苯基磷酰)亚胺(Htpip)作为O^O型辅助配体,合成了两种新型磷光金属铱配合物(pymbt)2Ir(tpip) (Ir1)和(pymbtp)2Ir(tpip) (Ir2)。通过核磁共振氢谱、质谱和元素分析对其进行了结构表征,用紫外-可见吸收光谱和荧光发射光谱进行了光物理性质的研究。结果表明,铱配合物Ir1和Ir2在溶液中的最大发射峰分别为563 nm和619 nm,为橙黄光和红光。在无水无氧二氯甲烷溶液中相对量子效率分别为6.3%和10.1%,磷光寿命为0.50 ms和0.63 ms。同时采用含时密度泛函理论(TDDFT)对配合物Ir1和Ir2的最低能量电子跃迁进行了计算,结果与实验测得的相应光谱数据对应的趋势相符。     

一种2-苯基吡啶铱配合物的合成及结构表征

采用无水无氧真空线技术(Schlenk),以氯桥二聚体(ppy)_2Ir(μ-Cl_2)Ir(ppy)_2为原料,在碱性条件下与配体苯甲酰丙酮反应合成出磷光材料配合物Ir(ppy)_2(bza)。通过调整反应物比例,缩短了反应时间,产率提高至83%。采用元素分析、核磁共振谱(~1H-NMR、~(13)C-NMR)、质谱和红外光谱等表征手段,确定了产物的分子结构。     

[Ir(ppy)2(dcbpy)]PF6的合成、表征及光物理性能研究

以氯桥二聚体(ppy)2Ir(μ-Cl2)Ir(ppy)2、4,4''-二羧基-2,2''-联吡啶和六氟磷酸铵为原料合成了一种阳离子型铱配合物[Ir(ppy)2(dcbpy)]PF6,产率94.9%。并通过元素分析、质谱、红外光谱以及核磁共振谱表征确认了目标产物的分子结构。以溶剂缓慢挥发法培养出配合物单晶,经X射线单晶衍射仪表征、计算,获得了晶体结构参数。紫外-可见吸收光谱和光致发光光谱的研究表明,该配合物常温最大发射位于582 nm处,显示发射强烈的黄光。     

1,5-环辛二烯(乙酰丙酮)铱(Ⅰ)的合成及结构表征

在四氢呋喃介质中,将1,5-环辛二烯氯化铱(Ⅰ)二聚体([Ir(cod)Cl]_2)与乙酰丙酮加热回流,一步合成了1,5-环辛二烯(乙酰丙酮)铱(Ⅰ)[Ir(acac)(cod)],产率88.6%。用元素分析、红外光谱(IR)和核磁共振(~1H-NMR、~(13)C-NMR)等分析,结果表明产物为目标化合物。     

两种新型铱(Ⅲ)配合物的合成与性质研究

分别以2-苯基吡啶(ppy)为第一配体,以1-苯基-1,3-丁二酮(phbd),1-苯基-3-甲基-4-苯甲酰基-吡唑啉酮-5(pmbp)为第二配体合成了两个新的铱配合物Ir(ppy)2(pmbp)、Ir(ppy)2(phbd),通过红外光谱、元素分析和核磁共振对其化学组成进行了结构表征,表征结果与理论吻合良好;配合物在紫外吸收光谱图上的290~310 nm处出现了强的配体自旋允许的单重态π-π*跃迁吸收峰,在400~460 nm处出现了配合物分子内金属铱到配体的单重态和三重态电荷跃迁吸收峰(1MLCT和3MLCT);同时配合物Ir(ppy)2(pmbp)、Ir(ppy)2(phbd)在荧光光谱上522、518 nm处出现了强的绿光发射。     

两种离子型铱配合物的合成、光物理性质及对OH-的检测

以两种2,2’-联吡啶衍生物为中性配体,2-(3-氟苯基)吡啶为环金属配体,合成了两种新型的离子型Ir(Ⅲ)配合物Ir1和Ir2。利用核磁、质谱和晶体结构分析确认了配合物Ir1和Ir2的结构。配合物Ir1和Ir2在CH₂Cl₂溶液中的最大发射波长分别为570和528 nm,为橙红光和黄光。两种配合物在无氧CH₂Cl₂溶液中的量子产率分别为0.88和0.57,磷光寿命分别为2.43和2.40μs。通过理论计算详细讨论了中性配体的取代基种类对其光谱性质的影响。在配合物Ir1的DMSO/H₂O溶液中加入OH^-后,其发射峰强度提高了近100倍,溶液的发光颜色由红色变为明亮的绿色,检出限为8.47×10^-6 mol/L。机理研究表明,OH^-取代了Ir1的中性配体上的溴取代基,形成了新的含有羟基的配合物,从而改变了Ir1的光谱特性,实现对OH^-的高选择性和高灵敏度检测。     

Investigation of double emissive layer structures on phosphorescent blue organic light-emitting diodes

The performances of blue phosphorescent organic light-emitting diodes (PHOLEDs) at high current densities have been investigated with double emissive layer structures (D-EMLs). The D-EMLs are comprised of two emissive layers with a hole-transport-type host of N,N′-dicarbazolyl-3,5-benzene (mCP) and an electro transport-type ultrawide band-gap host of m-bis-(triphenylsilyl)benzene (UGH3) both doped with a blue electro-phosphorescent dopant of iridium(III)bis(4,6-difluorophenyl-pyridinato-N,C^2′) picolinate (FIrpic). The expansion of hole/electron recombination zone in D-EMLs has been successfully achieved by controlling of each EML properties, therefore external quantum efficiency, especially at high current density region was significantly enhanced. Moreover, the blue PHOLED with D-EMLs showed substantially reduced roll-off with the external quantum efficiency of 10.0% at 5000 cd/m².     

High color rendering white organic light-emitting diodes fabricated using a broad-bandwidth red phosphorescent emitter for lighting applications

High color rendering white organic light-emitting devices (WOLEDs) were developed using a broad-bandwidth red phosphorescent iridium complex, bis[2-(1-naphthyl)benzothiazolato-N,C²′]iridium(III) acetylacetonate [Ir(absn)₂(acac)]. The red phosphorescent emitter Ir(absn)₂(acac) was used to fabricate blue–red and blue–green–red WOLEDs by combining blue-emitting bis[2-(4,6-difluorophenyl)pyridinato-N,C²′]iridium(III) picolinate (FIrpic) and green-emitting tris-fac-(2-cyclohexenylpyridine) iridium (III) [Ir(chpy)₃] in multiple-emissive layers. Mixed host emissive layers were employed using a hole-transport-type host 4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA) and an electron-transport-type host 2,6-bis[3-(carbazol-9-yl)phenyl]pyridine (DCzPPy) for efficient charge carrier injection. Di-[4-(N,N-ditolyl-amino)-phenyl]cyclohexane (TAPC) and 1,3-bis(3,5-dipyrid-3-yl-phenyl)benzene (BmPyPB) were used as the hole and electron transporting layers, respectively. The effects of the emissive layer thickness and the doping ratios of different color dopants on WOLED performances were investigated. The WOLED based on ITO/TAPC/TCTA:FIrpic (10%):Ir(absn)₂(acac) (4%)/TCTA:Ir(chpy)₃ (9%, 6 nm)/DCzPPy:FIrpic (13%):Ir(absn)₂(acac) (4%)/BmPyPB/LiF/Al exhibited an external quantum efficiency of 10.7%, a power efficiency of 23.0 lm/W, a very high color rendering index (CRI) of 88.1, and a correlated color temperature (CCT) of 2629 K at 1000 cd/m².     

Efficiency improvement of blue phosphorescent organic light emitting diodes by using a stacked emitting structure

Quantum efficiency of blue phosphorescent organic light emitting diodes (PHOLEDs) was improved by using a stacked emitting structure which can balance holes and electrons in light emitting layer. N,N′-dicarbazolyl-3,5-benzene (mCP) doped with iridium(III) bis(4,6-(di-fluorophenyl)-pyridinato-N,C2′) picolinate (FIrpic) was used as an emitting layer with good hole injection properties near hole transport layer and 1,3-bis(triphenylsilyl)-benzene (TSB) doped with FIrpic was used as an emitting layer with good electron injection properties near electron transport layer. High quantum efficiency of 10.2% was obtained at 500 cd/m² compared with 7.5% and 7.6% of mCP and TSB reference devices.     

双[2-(对甲苯基)吡啶]乙酰丙酮合铱的合成及结构表征

以水合三氯化铱为原料,2-(对甲苯基)吡啶作环金属配体、乙酰丙酮作辅助配体合成了双[2-(对甲苯基)吡啶]乙酰丙酮合铱[(tpy)2Ir(acac)],通过质谱、氢谱、X射线单晶衍射分析表征手段确证了其分子结构。通过紫外可见光谱和光致发光光谱分析,研究了该配合物的光物理性能,在410和461 nm处有单重态和三重态吸收,在516 nm处有较强的绿光发射,表明该配合物是一种绿光材料。     

黄光铱配合物Ir(dmppy)2(popy)的合成及光物理性能研究

设计合成了一种新的中性铱磷光配合物Ir(dmppy)2(popy),该配合物以2,4-二(3,5-二甲基苯基)吡啶为环金属配体,2-(2-羟基苯基)吡啶为辅助配体。通过核磁共振氢谱和碳谱(¹H-NMR、¹³C-NMR)确证了配合物的化学结构,采用光致发光光谱和紫外可见光谱研究了配合物的光物理性能,采用热分析研究了配合物的热稳定性。该配合物在二氯甲烷中的最大发射波长为575 nm,为黄光发射铱磷光配合物。     

Highly efficient blue phosphorescent organic light-emitting devices using simple structures with thin 1,1-bis[(di-4-tolyamino)phenyl]cyclohexane layers

We have developed highly efficient blue phosphorescent organic light-emitting devices with thin 1,1-bis[(di-4-tolyamino)phenyl]cyclohexane (TAPC) layers. We used simple three organic layers: TAPC, iridium(III) bis[[4,6-di-fluorophenyl]-pyridinato-N,C^2′] picolinate (FIrpic) doped N,N′-dicarbazolyl-3,5-benzene (mCP), and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layers. The device structure was ITO/TAPC (x nm)/mCP:FIrpic (5 nm, 10%)/BCP (55 nm)/LiF/Al. The 4 nm TAPC device shows current efficiency and power efficiency of 34 cd/A and 15.1 lm/W, respectively, at a luminance of 1540 cd/m². We investigate the effect of TAPC thickness on the current efficiency, power efficiency, driving voltage, and electroluminescence characteristics.     

Diphenylsilanes containing electronically isolated carbazolyl fragments as host materials for light emitting diodes

Branched derivatives containing diphenylsilane core and pendent carbazol-9-yl fragments were synthesized and characterized. The compounds represent amorphous materials of high thermal stability with glass transition temperatures of 54–93 °C and thermal decomposition starting at temperatures above 391 °C. The electron photoemission spectra of layers of the synthesized compounds showed ionization potentials of ca 5.9 eV. The derivatives were tested as host materials in phosphorescent OLEDs with iridium(III)[bis(4,6-difluorophenyl)-pyridinato-N,C2′]picolinate as the guest. The device with the host derivative containing four isolated carbazolyl fragments exhibited the best overall performance with maximum current efficiency of 16.4 cd/A and maximum brightness exceeding 200 cd/m²_.     

Highly efficient bilayer blue phosphorescent organic light-emitting devices

We have developed highly efficient blue phosphorescent organic light-emitting devices comprising of two organic layers. Hole transporting 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (TAPC) was used as an emitting host for iridium(III)bis[(4,6-di-fluorophenyl)-pyridinato-N,C²′]picolinate (FIrpic) guest. In our bilayer system, the host–guest energy transfer process leads to a low optimal doping concentration of 2 wt%, while the better charge balance is achieved by the better electron injection into the host layer from electron transport layer. Using these bilayer structures, we demonstrate a maximum current efficiency of 34 cd/A in the device structure of ITO/TAPC: FIrpic (30 nm, 2 wt%)/3-(4-biphenyl-yl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (50 nm)/LiF/Al.     

Broad band and white phosphorescent polymer light-emitting diodes in multilayer structure

Efficient phosphorescent polymer light-emitting diode with poly(vinylcarbazole) (PVK) doped by two or three iridium complexes in single and bilayer structures are studied. With (tris-(2-4(4-toltyl) phenylpyridine) (Ir(mppy)₃) as the green emitter and (1-phenylisoquinoline) (acetylacetonate) iridium(III) (Ir(piq)₂) as the red emitter the efficiency is as high as 23 cd/A with broad band emission from 500 nm to 720 nm. For white emission a second layer is added with blue emitter ((III) bis[(4,-6-di-fluorophenyl-pyridinato)N,C²] picolinate) (FIrpic) doped in PVK. White light containing three spectral peaks results with efficiency 8.1 cd/A. As the second blue layer is replaced by the fluorescent (poly(9,9-dioctylfluorene)) (PFO) white emission with high color rendering index 86 is achieved. The efficiency is 5.7 cd/A with peak luminance 8900 cd/m². For a given iridium complexes ratio the relative intensity of the green and red emission depends sensitively on the second blue layer.