内含C60掺杂空穴传输层的量子点电致发光器件

聚乙烯咔唑（PVK）中掺入富勒烯（C₆₀）的重量比从0%到10%变化,以研究在空穴传输层中掺杂C₆₀后对量子点电致发光器件性能的影响。掺入C₆₀后的PVK薄膜在氧化铟锡（ITO）基底上均方根粗糙度从3nm降至1.6nm。另外,掺入C₆₀后有利于空穴的注入和传输,改善器件中电子和空穴的平衡,提高了器件的效率。     

稀土铽配合物有机电致发光

利用三价稀土铽配合物作为发射层、二胺衍生物(TPD)以及聚乙烯咔唑(PVK)作为空穴传输层制备了有机电致发光器件. 器件的结构为 玻璃衬底/ITO/PVK 或者TPD/Tb3+ 配合物/Al, 其中空穴传输层TPD 和发光层Tb3+-配合物采用热蒸发办法成膜. 而空穴传输层PVK采用旋甩涂敷的方法成膜. 对于以上的两种器件均获得了来自Tb3+ 的窄峰发射, 在直流电压15.4 V驱动下, 器件发光亮度达210 cd·m-2.     

磷光客体三重态能级对基于PVK主体的电致发光器件的影响

将磷光客体掺入PVK:PBD主体材料中是获得高效率磷光电致发光器件 (PhPLED)的有效途径.然而,分别掺杂Ir(pppy)₃、Ir(F-pppy)₃和Ir(F₂-pppy)₃三种磷光客体的PhPLED器件性能件却显著不同.我们分别模拟主-客体间能量转移和客体直接捕获电子空穴对两种机制,研究了三种客体材料的磷光发射及其衰减过程.研究表明:平衡的载流子注入和客体高效率的载流子捕获是实现Ir-配合物掺杂的PhPLED器件性能优良的主要机制,PVK较低的三重态能级使其无法成为蓝光磷光电致发光器件的主体,在PVK中掺入PBD的方法,则进一步降低了主体材料的三重态能级,这是蓝光磷光电致发光器件运行效率较低的主要原因.本文的研究结果可为高分子磷光电致发光器件的制备技术和新型磷光主体的设计提供参考.     

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.     

输运层厚度对双层有机器件复合发光的影响

采用ITO/PVK/Alq/Al双层电致发光(EL)结构,制备了三种载流子输运层厚度分别为30、 60、 120 nm,发光层厚度均为300 nm的有机薄膜EL器件,测试其EL谱及J-V特性曲线.根据有机EL器件中载流子的产生和输运过程导出了载流子复合几率及电子和空穴密度分布表示式,用以解释其发光强度随输运层厚度的变化关系,用一维无序结构载流子随机跃迁模型讨论输运层厚度对器件电流密度及启动电压的影响,探讨了载流子在薄膜中的输运过程,其理论与实验符合得很好.     

氧化石墨烯掺杂PEDOT:PSS作为空穴注入层对有机发光二极管发光性能的影响

研究了氧化石墨烯(GO)掺杂聚(3,4-亚乙二氧基噻吩):聚(苯乙烯磺酸) (PEDOT:PSS)作为空穴注入层对有机发光二极管发光性能的影响. 在PEDOT:PSS水溶液中掺入GO, 经过湿法旋涂和退火成膜后, 不仅提高了空穴注入层的空穴注入能力和导电率, 透光率也得到了相应的提高, 从而使得有机发光二极管(OLED)器件的发光性能得到了提升. 通过优化GO掺杂量发现, 当GO掺杂量为0.8%(质量分数)时, 空穴注入层的透光率达到最大值(96.8%), 此时获得的OLED器件性能最佳, 其最大发光亮度和最大发光效率分别达到17939 cd·m^-2和3.74 cd·A^-1. 与PEDOT:PSS 作为空穴注入层的器件相比, 掺杂GO后器件的最大发光亮度和最大发光效率分别提高了46.6%和67.6%.     

C_(60)与MoO_3混合材料做空穴注入层的单层有机电致发光器件

我们制备研究了基于结构为氧化铟锡(ITO)/C_(60)(1.2nm):MoO_3(0.4nm)/1,3,5-三(1-苯基-1H-苯并咪唑-2-基)苯(TPBi):三(2-苯基吡啶)铱[Ir(ppy)_3](33%,90 nm)/LiF (0.7 nm)/Al (120 nm)的高效绿色磷光单层有机发光二极管(OLED)。分别将C_(60),MoO_3与C_(60):MoO_3混合物作为空穴注入层(HIL)作为对比。TPBi在发光层中起着主体以及电子传输材料的双重作用。在使用电子传输型主体的单层OLED中,空穴注入层性质对于调节电子/空穴注入以获得电荷载流子传输平衡起重要作用。因此,适当调节空穴注入层是实现高效单层OLED的关键因素。由于MoO_3较大的电子亲和能(6.37 eV)会诱导电子从C_(60)的最高占据分子轨道(HOMO)能级转移至MoO_3,从而形成C_(60)阳离子,并使得Mo元素的价态从+6降至+5,C_(60):MoO_3混合就可以较好的调节空穴注入性质。最终实现最大电流效率为35.88 cd·A~(-1)的单层有机发光器件。     

芴-呋喃苯并噻二唑共聚物的光电性能

对芴-呋喃苯并噻二唑共聚物的吸收光谱、光致发光光谱、电致发光性能和光伏性能进行了研究. 共聚物在382 nm和530 nm处有两处明显的吸收峰, 其中530 nm处的吸收强度随着共聚物中呋喃苯并噻二唑单元(FBT)含量的增加而增加. 随着FBT单元含量的增加, 电致发光峰值从611 nm红移至702 nm. 以PVK为空穴传输层, 共聚物PFO- FBT0.1为发光层的发光器件, 在33 mA/cm2电流密度下的外量子效率达2.32%, 亮度为441 cd/m2. 实验中观察到快速的链内能量陷阱过程(从芴到FBT单元). 以共聚物PFO-FBT50为电子给体、PCBM为电子受体(重量比1:2)共混制备的光电池能量转换效率为1.13%, 开路电压0.85 V, 短路电流3.39 mA/cm2, 光谱响应边延伸至近750 nm.     

二-[2',6'-二氟-2,3'-联吡啶- N,C4'][2,4-戊二酮-O,O]铱(III)的合成及其光致和电致发光性能

以2',6'-二氟-2,3'-联吡啶(Hdfpypy)为主配体,乙酰丙酮为辅助配体,合成了二-[2',6'-二氟-2,3'-联吡啶-N,C4'][2,4-戊二酮-O,O]铱(Ⅲ)配合物((dfpypy)2Ir(acac))。在THF溶液中,该配合物溶液最大光致发光光谱为465 nm(半峰宽为53 nm),同时伴有490 nm的肩峰,与面式-Ir(dfpypy)3在438和463 nm两个强度相近的发光光谱相比,发生了红移。配合物在脱气四氢呋喃溶液中的PL量子效率为0.41。将(dfpypy)2Ir(acac)以不同的浓度掺杂在主体材料聚乙烯基咔唑(PVK)中,制备了器件结构为:ITO/PEDOT∶PSS(聚二氧乙基噻吩∶聚对苯乙烯磺酸)/PVK∶(dfpypy)2Ir(acac)(100∶x)(70 nm)/Ba/Al的蓝色聚合物发光器件(x代表掺杂量)。在驱动电压为15.4 V时,2%掺杂器件的最大发光亮度为1400 cd/m2。当电流密度为0.23×10-3A/cm2时,2%掺杂器件最大亮度效率(ηc)为1.6 cd/A。器件的色坐标(CIE)值为(0.15,0.27)。     

铽配合物TbY(o-MBA)6(phen)2与PVK掺杂体系的发光性质研究

合成了一种新型的稀土铽配合物材料TbY(o-MBA)6(phen)2,把它作为发光材料应用于有机电致发光中.把铽配合物掺杂在导电聚合物PVK中采用旋涂法制得发光层,并利用AlQ作为电子传输层制作了多种结构的电致发光器件 器件A,ITO/PVK∶TbY (o-MBA)6(phen)2/LiF/Al;器件B,ITO/PVK∶TbY (o-MBA)6(phen)2/AlQ/LiF/Al;器件C,ITO/PVK∶TbY (o-MBA)6(phen)2/BCP/AlQ/LiF/Al.对器件A和B得到了纯正的、明亮的Tb3+离子的绿光发射,4个特征峰分别对应着能级5D4到7Fj(j=6,5,4,3)的跃迁,而PVK的发光完全被抑制.研究了掺杂体系的光致发光性能和电致发光性能,认为在光致发光中,铽的发光主要来源于PVK到稀土配合物的Frster能量传递.而在电致发光中,铽的发光主要来源于稀土配合物直接捕获载流子形成激子复合发光.并通过优化选择得到了发光性能较好的器件B,其最大亮度在14 V时达到213 cd·m-2.     

Synthesis and characterization of light‐emitting oligo(p‐phenylene‐vinylene)s and polymeric derivatives containing three‐ and five‐conjugated phenylene rings. II. Electro‐optical properties and optimization of PLED performance

A series of multilayer polymeric light‐emitting diodes (PLEDs) containing an electron‐transporting layer (ETL), that is tris(8‐quinolinolato)‐aluminum(III) (Alq) and 2,2′,2″‐(1,3,5‐phenylene)‐tris[1‐phenyl‐1H‐benzimidazole] (TPBI), were fabricated by doping fluorescent oligo(p‐phenylene‐vinylene)s (BIII and BV) and polymer derivatives (PBV) into poly(N‐vinyl carbazole) (PVK). These PLEDs can be optimized by the design of multilayer device configurations (brightness increased 8–15 times by addition of ETL) and possess greenish electroluminescent (EL) spectra peaked about 500–540 nm. A remarkably high brightness of 56,935 cd/m² with a power efficiency of 3.25 lm/W was obtained in the device of PVK:BVOC₈‐OC₈ (100:20)/Alq (60 nm/60 nm). It suggests that the emission mechanism (including the conjugated and excimer emissions of BVOC₈‐OC₈ emitters) originates from both of BVOC₈‐OC₈ and ETL (Alq and TPBI) by varying the concentration of chromophores and adjusting the thickness of ETL. The concentration effect of the emitters in PVK (i.e. PVK:BVOC₈‐OC₈ = 100:5, 100:20, and 100:100 wt %) and the influence of the ETL (including its thickness) on the EL characteristics are also reported. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2922–2936, 2006     

Mass spectrometric investigation of the aggregation and coalescence of fullerenes in C60-modified poly(N-vinylcarbazole) by UV-laser ablation

The phenomena of aggregation and coalescence of fullerenes in the UV-laser ablation time-of-flight mass spectrometric investigation of C₆₀-modified poly(N-vinylcarbazole) both in the positive and in the negative ion channels have been observed. The results indicate that in C₆₀ chemically modified PVK (C₆₀–PVK) copolymer the nascent fullerene fragments ruptured from main chain can easily coalesce into large fullerenes through collisions, whereas in the C₆₀-doped PVK the aggregation and coalescence of C₆₀ were relative weak due to nonbounding action and incomplete charge transfer behavior between C₆₀ and PVK. Furthermore, the photoinduced electron transfer behavior between C₆₀ and carbazole units in the C₆₀ chemically modified poly(N-vinylcarbazole) in benzonitrile by laser flash photolysis at 355 nm has also been investigated. Efficiency of the anion radical of C₆₀ in copolymer at 1080 nm is higher than that of the C₆₀-doped poly(N-vinylcarbazole) polymers. The formation of a C₆₀ radical anion may be ascribed to photoinduced electron transfer between C₆₀ pendanted on the main chain backbone and the inter-, and intrachain carbazole units in the copolymer. © 1997 John Wiley & Sons, Inc. 35 : 1185–1190, 1997     

Electroplex emission from a blend of poly(N-vinylcarbazole) and 2,9-dimethyl-4,7-diphenyl-1, 10-phenanthroline

The PL and EL spectra of poly(N-vinylcarbazole) (PVK) : 2,9-dimethyl-4,7-diphenyl-1, 10-phenanthroline (BCP) (1:1 w/w) film were found completely different. The PL spectrum is a single peak at 415 nm that originates from excitons emission from PVK, and the tail of the spectrum is suggested to be excimer emission from BCP molecules. However, a new emission at 595 nm was found in the EL spectra of devices ITO/PEDOT:PSS(50 nm)/PVK:BCP(1:1)(100 nm)/Al. After aggregate, exciplex and product of electrochemical reaction were ruled out, the new emission was proposed to be electroplex emission that occurred between PVK and BCP molecules. Under high voltage, only electroplex emission can be observed in the EL spectra.     

The synthesis and characterization of C60 chemically modified poly(N-vinylcarbazole)

Addition of C₆₀ moiety, a powerful electron acceptor to poly(N-vinylcarbazole) (PVK) by chemical reaction modifies considerably the physical and chemical properties of PVK. The characterization techniques employed are UV-visible, IR, DSC, TGA, ESR, ¹³C-NMR spectroscopy, scanning electron microscopy, XRD, and cyclic voltammetry. The fullerenated PVK, which has a visibly earthy yellow cast when compared with the unreacted polymer, has a new structure in the UV-vis absorption spectrum with the active range extending from about 280 to 870 nm, its apparent temperature sensitivity is intriguing, and an unusual temperature dependence for the ESR spectrum is observed. Considerable difference of electronic structure between pure PVK and C₆₀-PVK copolymer is indicated. The thermal stability and oxidation-reduction activation of pure PVK are enhanced by C₆₀-chemical modification. © 1996 John Wiley & Sons, Inc.     

模板法制备聚乙烯咔唑及其复合物纳米管有序阵列

近十几年来,纳米管引起了人们越来越多的关注,不仅仅是由于它独特的性质,也因为它们在电、磁以及光电器件上具有广泛的应用前景。纳米管的制备方法大体上分为两种:自组装法[1￣3]和模板法[4￣7]。尽管自组装法已成功地制得了一些纳米管,但由于它对构造纳米管的材料有着较严格的     

Fast switching response and dielectric behaviour of fullerene/ferroelectric liquid crystal nanocolloids

The electro-optical and dielectric responses of the fullerenes C₆₀-doped ferroelectric liquid crystal (FLC) nanocolloids are reported. Order parameter and phase transition temperature remain invariant as a function of varying dopant concentration (0.10 wt% to 0.50 wt%). Faster switching response of nanocolloids comparing to that of the non-doped FLC is manifested by increase in the localised electric field (around 76% increment for 0.50 wt%), while reduction in the spontaneous polarisation could be the result of anti-parallel correlation amid dopant and FLC dipoles. Decrease in dielectric constant, absorption strength, dielectric strength and rotational viscosity of FLC nanocolloids than that of non-doped FLC is the other consequence of C₆₀ doping. Goldstone-mode relaxation frequency is found to be increased with increasing doping concentration of C₆₀ in FLC.     

Covalent Modification of MoS2 with Poly(N‐vinylcarbazole) for Solid‐State Broadband Optical Limiters

New soluble MoS₂ nanosheets covalently functionalized with poly(N‐vinylcarbazole) (MoS₂–PVK) were in situ synthesized for the first time. In contrast to MoS₂ and MoS₂/PVK blends, both the solution of MoS₂–PVK in DMF and MoS₂–PVK/poly(methyl methacrylate) (PMMA) film show superior nonlinear optical and optical limiting responses. The MoS₂–PVK/PMMA film shows the largest nonlinear coefficients (β_eff) of about 917 cm GW^?1 at λ=532 nm (cf. 100.69 cm GW^?1 for MoS₂/PMMA and 125.12 cm GW^?1 for MoS₂/PVK/PMMA) and about 461 cm GW^?1 at λ=1064 nm (cf. ?48.92 cm GW^?1 for MoS₂/PMMA and 147.56 cm GW^?1 for MoS₂/PVK/PMMA). A larger optical limiting effect, with thresholds of about 0.3 GW cm^?2 at λ=532 nm and about 0.5 GW cm^?2 at λ=1064 nm, was also achieved from the MoS₂–PVK/PMMA film. These values are among the highest reported for MoS₂‐based nonlinear optical materials. These results show that covalent functionalization of MoS₂ with polymers is an effective way to improve nonlinear optical responses for efficient optical limiting devices.     

2-(N-十六烷基氨基甲酰基)-8-羟基喹啉镉配合物的电致发光

本文首次报道了采用2-(N-十六烷基氨基甲酰基)-8-羟基喹啉镉配合物作为一种新型发光材料，通过LB膜技术来制备发光层所制得的电致发光器件。在室温下，当直流正向偏压为6.5 V时，可于暗室中用肉眼观察到发光。当电流密度为35 mA/cm²时，可得稳定的发光，其电致发光图谱峰值在490 nm处。     

NARROW BANDWIDTH BRIGHT SCARLET ORGANIC ELECTROLUMINESCENT DEVICE BASED ON N,N'-BIS[4-(N,N-DIMETHYLAMONO)-BENZYLIDENE]-DIAMINOMALEONITRILE DYE

A novel red dye, N, N'-bis[4-(N,N-dimethylamino)-benzylidene]diaminomaleonitrile (BAM), was prepared by reacting diaminomaleonitrile with 4-(N,N-dimethylamino)-benzaldehyde and were characterized by ¹H NMR, UV absorption and photoluminescence. The BAM dye showed an absorption peak wavelength of 530 nm and bright photoluminescence with a peak wavelength at 675 nm. It was used as the doped emitter for fabricating a bright scarlet organic electroluminescent (EL) device. The structure of the double-layer EL device consisted of a hole-transport layer and a luminescent layer between ITO glass and magnesium electrodes. The hole-transport layer was a poly(N-vinylcarbazole) (PVK) film. The luminescent layer consisted of a host material, 8-hydroxyquinoline aluminum (Alq₃), and BAM dye as the dopant. A bright light with the peak of 620 nm and narrow bandwidth of 50 nm was obtained in the device with a maximum luminance of 6230 cd/m². The emission spectra almost unchanged as the luminance increased with increasing injection current and the bias voltage. A tentative explanation from both the electronic distribution viewpoint and the molecular geometric analysis for the narrow bandwidth of this red dye was offered.