有机小分子掺杂的聚合物发光二极管电致发光及其发射机制

在新型空穴传输聚合物聚TPD(PTPD)中掺杂电子传输有机小分子荧光染料Rubrene制成薄膜器件.考察了影响聚合物掺杂小分子薄膜器件发光性能的因素.实验表明,通过在器件中掺杂,可以控制器件所发光的颜色.研究了PTPD掺杂Rubrene分子薄膜的电致发光光谱和光致发光光谱.由实验可知.在光致发光中存在从PTPD向Rubrene的能量传递和电荷转移,而电致发光则存在从PTPD向Rubrene的能量传递和Rubrene分子对载流子的俘获.即掺杂器件的发射机制为载流子陷阱和Forster能量转换过程的共同作用.     

聚合物/有机小分子异质结掺杂型电致发光二极管及其发射机制

为了提高有机电致发光器件的效率和稳定性,制作了聚合物/有机小分子异质结掺杂型电致发光二极管.它以新型PTPD(聚TPD)为空穴传输材料,高效荧光材料Rubrene为掺杂剂.异质结基本结构为PTPD/Alq3,双层掺杂时,器件电致发光的量子效率大约是未掺杂器件的两倍;与未掺杂器件和常用的TPD/Alq3二极管相比,掺杂器件的稳定性有了显著的提高.从电致发光光谱可知,掺杂器件的发射机制为载流子陷阱和Forster能量转换过程的共同作用.     

聚合物/有机小分子异质结掺杂型电致发光二极管及其发射机制

为了提高有机电致发光器件的效率和稳定性,制作了聚合物/有机小分子异质结掺杂型电致发光二极管.它以新型PTPD(聚TPD)为空穴传输材料,高效荧光材料Rubrene为掺杂剂. 异质结基本结构为PTPD/Alq3,双层掺杂时,器件电致发光的量子效率大约是未掺杂器件的两倍;与未掺杂器件和常用的TPD/Alq3二极管相比,掺杂器件的稳定性有了显著的提高. 从电致发光光谱可知,掺杂器件的发射机制为载流子陷阱和Frster能量转换过程的共同作用.     

染料掺杂聚合物电致发光薄膜的能量传递

聚合物薄膜电致 姚器件是当前国际上的一个研究热点，文中利用吸收光谱和荧光光谱研究了聚乙烯咔唑溶液和薄膜中，聚合物分子与染料分子之间的相互作用及其可能的能量传递，结果表明，染料掺杂的聚合物电致发光器件中来自染料的发光不一定源于ｏｒｓｔｅｒ共振能量传递。     

掺杂型有机电致发光器件中载流子的俘获机制

掺杂型有机电致发光器件中,掺杂剂的发光来源于基质的能量传递或者来源于掺杂剂对载流子的俘获,也有可能两种机制同时存在。为了揭示掺杂型器件发光中究竟哪种机制占主导,以联苯乙烯衍生物(amino substituteddistyrylarylenederivative,BCzVB)掺杂4,4‘ 双(9 咔唑基) 1,1‘ 联苯(4,4‘ N,N‘ dicarbazole biphyenyl,CBP)为发光层的器件中,通过电流 电压特性的分析表明器件的发光主要来源于载流子俘获机制。光致发光与电致发光对比分析也表明,器件的发光过程中载流子俘获机制起了主导作用。     

掺杂型异质结有机电致发光二极管及其稳定性

研制了高效率、高稳定性的聚合物／有机物异质结掺杂型电致发光二极管（LED）,它以新型聚合物三苯基二胺衍生物（PTPD）为空穴传输材料,高效荧光材料红荧稀（Rubrene）为掺杂剂,异质结基本结构为PTPD／Alq3。双层掺杂时,器件电致发光（EL）的量子效率为1．47％,大约是未掺杂异质结器件0．74％的2倍;与未掺杂器件和常用的TPD／Alq3二极管相比,掺杂器件的稳定性有了显著的提高。讨论了异质结掺杂型LED稳定性改善机理。     

染料掺杂剂的位置对有机电致发光器件性能的影响

利用3种有机小分子荧光染料dimethylquinacridone(DMQA),4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4Hpyran(DCJTB)和5,6,11,12-tetraphenylnaphthacene(Rubrene)作为掺杂剂,研究了其掺杂位置对于有机电致发光器件(OLED)性能的影响。利用Fo¨rster能量传递(ET)理论和直接载流子俘获(DCT)理论,结合器件的电致发光(EL)光谱,讨论了这3种材料作为掺杂染料的类型。实验结果表明,小分子荧光染料DMQA、DCJTB和Rubrene同时具有ET型和DCT型掺杂剂的双重特性;另外,掺杂剂的位置对器件的EL光谱有较大影响,并讨论了EL光谱差异的形成原因。     

聚乙烯基咔唑对稀土络合物发光特性的影响

本文报导了稀土红色荧光络合物－Eu(TTA)m复合体系与聚乙烯基咔唑（PVK）共混体系的光致发光和电致发光性质。通过对吸收光谱和发射光谱的测量,可知在光致发光中存在PVK向Eu(TTA).复合体系的能量传递,但在较大的掺杂浓度下仍存在来自PVK的发光.在电场激发条件下,此共混体系的电致发光仅有稀土络合物的特征发光而很难看到PVK的特征发光.并且这种电致发光器件的稳定性明显改善,另外在器件结构中加入电子传输层可明显提高器件的发光效率.     

掺杂Rubrene双发光区有机黄光器件的制作

制作了在N,N′-diphenyl-N,N′-bis-1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine(NPB)和aluminium-tris-8-hydroxy-quinoline(Alq3)中分别掺杂黄色荧光染料5,6,11,12,-tetraphe-nylnaphthacene(Rubrene)的双发光区有机黄光电致发光器件。器件的结构为ITO/NPB(30nm)/NPB∶Rubrene(20nm)/Alq3∶Rubrene(20nm)/Alq3(30nm)/LiF(0.8nm)/Al。NPB作为空穴传输层材料,Alq3作为电子传输材料,NPB和Alq3中掺杂Rubrene的浓度分别为0.9%和1.4%。实验结果表明,由于Rubrene具有较强的载流子俘获能力,而且在Alq3和NPB层中进行掺杂,相对于单掺杂层器件为Rubrene提供了更多的俘获空位,从而提高了器件的性能。     

聚合物电致发光器件的研究进展

聚合物电致发光器件（ＥＬＤ）因其具有许多无机及有机小分子ＥＬＤ所不具备的优点，成为电致发光领域研究的热点。通过掺杂或适当的分子设计可以调谐发光颜色。介绍和评述了聚合物电致发光原理、电致发光器件、电致发光材料的开发及应用前景。     

Enhanced green electrophosphorescence by using polyfluorene host via interfacial energy transfer from polyvinylcarbazole

For green-emitting Ir complex-doped polymer devices, high efficiencies have been achieved only when non-conjugated poly(N-vinylcarbazole) (PVK) was used as the host polymer. It is commonly believed that conjugated polyfluorenes (PFO) are not suitable for the use as host of green phosphorescent complexes due to the presence of the low-lying triplet state. In this paper we reported that despite very inefficient PL phosphorescent emission of Ir(Bu-PPy)₃ in the PFO films, strong green electroluminescence (EL) and high device efficiencies have been observed for devices from such blend films when multilayer device with PVK was used as anode buffer. We analyze the PL spectra in steady state and transient response and found that the energy transfer via PVK interlayer plays important role in the efficient EL performance. This fact clearly indicates the efficient electrophosphorescence might be achieved even if the triplet energy of phosphorescence dye is higher than that of the host. These findings could significantly broaden our selection in polymer hosts for phosphorescent devices.     

A Series of Energy‐Transfer Copolymers Derived from Fluorene and 4,7‐Dithienylbenzotriazole for High Efficiency Yellow,Orange, and White Light‐Emitting Diodes

Eight random and alternating copolymers PF‐DTBTA derived from 2,7‐fluorene and 4,7‐dithienylbenzotriazole (DTBTA) were synthesized. Thin solid films of the energy‐transfer copolymers possess high absolute photoluminescence (PL) quantum yields (Φ_PL) between 60?72%. Inserting PVK layer between anode and emissive layer could show higher electroluminescence (EL) performances due to PVK‐enhanced hole injection. Random copolymers PF‐DTBTA1?15, with DTBTA molar contents from 1% to 15%, displayed yellow EL spectra with high external quantum efficiency (EQE_max) up to 5.78%. PF‐DTBTA50, the alternating copolymer, showed an orange EL with EQE_max of 3.3%. The good Φ_PL and EQE_max of the PF‐DTBTA50 with very high DTBTA content indicate that DTBTA is a high efficiency chromophore with very low concentration quenching effects in the solid state PL and EL processes. PF‐DTBTA0.03?0.1 could emit white EL due to partial energy transfer from fluorene segments to DTBTA units. Moreover, white EL devices, with forward‐viewing maximum luminous efficiency up to 11 cd/A and stable white EL spectra (CIE coordinates of (0.33, 0.43)) in high current range from 5 mA to 60 mA, could be realized from the non‐doped polymer with simple binary structure. Our results suggest that DTBTA has big potential to construct high performanced EL polymers or oligomers.     

Study on Surface States of Zinc Sulfide Electroluminescence Thin Films

１ＩｎｔｒｏｄｕｃｔｉｏｎＺｉｎｃｓｕｌｆｉｄｅｉｓａⅡ－Ⅳｓｅｍｉｃｏｎｄｕｃｔｏｒｃｏｍｐｏｕｎｄｗｉｔｈｗｉｄｅｂａｎｄｇａｐ．Ｔｈｅｔｈｉｎｆｉｌｍｓｈａｖｅｅｘｃｅｌｅｎｔｃｈａｒａｃｔｅｒｓｏｆｅｌｅｃｔｒｏｌｕｍｉｎｅｓｃｅｎｃｅ（ＥＬ...     

有机白光LED

有机白光LED主要有电致发光与光致发光两类。电致发光的主要机理有:量子阱发光、激基复合物发光和能量转移。人们对有机电致发光白光LED研究较多,不久将有产品问世;而对光致发光研究较少。与电致发光相比,光致发光造价更小,其荧光量子效率或许比电致发光更高。有机白光LED制备工艺简单、成本低功耗小,具有巨大的应用价值及潜在的市场。对发光显示技术,有机白光LED代表了一条“便宜”经济的路径。综述了有机白光LED的机理及发展现状。     

NPB和5，6，11，12-四苯基四苯并在薄膜中的发光和能量传递

能量传递是发光材料中的重要现象。本文使用时间分辨光谱和发射光谱对ＮＰＢ（二胺衍生物）掺Ｒｕｂｒｅｎｅ（５，６，１１，１２－四苯基四苯并）有机薄膜的能量传递过程进行了研究，建立了动力学方程，得到了与实验值相拟合的结论。找到了产生白光的最佳掺杂比。然后制成带锁定层结构为ＩＴＯ／ＣｕＰｃ／ＮＰＢｌ：Ｒｕｂｒｅｎｅ／ＴＰＢｉ／Ａｌｑ／Ｍｇ：Ａｇ薄膜电致发光器件，结果却得不到白光发射，说明能量传递过程在电场     

Improved Efficiency of Single‐Layer Polymer Light‐Emitting Devices with Poly(vinylcarbazole) Doubly Doped with Phosphorescent and Fluorescent Dyes as the Emitting Layer

We demonstrate novel organic light‐emitting diode (LED) materials that contain a green phosphorescent dye (dmbpy)Re(CO)₃Cl (dmbpy = 4,4′‐dimethyl‐2,2′‐bipyridine), and a red fluorescent dye 4‐dicyanomethylene‐6‐(p‐dimethylaminostyryl)‐2‐methyl‐4H‐pyran (DCM) as dopants and polyvinylcarbazole (PVK) as the host. The photoluminescence (PL) and electroluminescence (EL) properties of these complex materials were studied. The energy transfer efficiency from PVK host to DCM is increased by the (dmbpy)Re(CO)₃Cl co‐dopant, which has an emission energy between that of PVK and DCM. The (dmbpy)Re(CO)₃Cl, which emits a long‐lived phosphorescence, is used as an energy coupler, providing the possibility to harvest both singlet and triplet energy in the devices. The pure red emission from DCM was observed from PL and EL spectra of (dmbpy)Re(CO)₃‐Cl(> 2.0 wt.‐%):DCM(> 0.5 wt. %) doped PVK films, demonstrating an efficient energy transfer from PVK and (dmbpy)Re(CO)₃‐Cl to DCM. By optimizing the concentration of DCM and (dmbpy)Re(CO)₃Cl in PVK, a maximum EL quantum efficiency of 0.42 cd A^–1 at a current density of 9.5 mA cm^–2 was obtained. The EL quantum efficiency of the doubly doped device is significantly enhanced in comparison with both a DCM‐only doped PVK device and a DCM‐doped PVK device with the green fluorescent dye Alq₃ as co‐dopant. The improvement in the operating characteristics of the phosphorescent and fluorescent dye doubly doped device is attributed to efficient energy transfer in the system, in which both triplet and singlet excitons are used for resultant emission in the polymer device.     

Host Selection and Configuration Design of Electrophosphorescent Devices

Recent studies on electrophosphorescent polymeric devices have demonstrated that charge‐trapping‐induced direct recombination on the phosphorescent dopant is of crucial importance. In this paper, we show that the electrochemical properties of phosphorescent molecules, which reflect their carrier‐trapping ability, may be a basic design criterion for the selection of host and device configuration. The systems, consisting of a red phosphorescent [Ru(4,7‐Ph₂‐phen)₃]²⁺ dopant and two blue hosts 2‐biphenyl‐4‐yl‐5‐(4‐tert‐butyl‐phenyl)‐[1,3,4]oxadiazole (PBD) and poly(vinylcarbazole) (PVK), are intensively studied. The triplet energy level of PVK and PBD is higher than that of the [Ru(4,7‐Ph₂‐phen)₃]²⁺, and both hosts show the ability of efficient energy transfer to the dopant, however, efficient electroluminescence (EL) is only obtained in the PVK‐host system. The combined studies of photoluminescence (PL), EL, and electrochemistry for doped films demonstrate that [Ru(4,7‐Ph₂‐phen)₃]²⁺, which undergoes a multielectron trapping process as it is used as a dopant in electron‐rich (n‐type) hosts, for instance, PBD, may induce an inefficient recombination for the resulting emission. Whereas using a hole‐rich (p‐type) polymer, such as PVK, as a host and inserting both hole‐blocking and electron‐transfer layers can effectively increase the efficiency of the corresponding devices up to 8.63 Cd A^–1, because of the reduced probability of multielectron trapping at the [Ru(4,7‐Ph₂‐phen)₃]²⁺ sites.     

一种新型蓝色有机电致发光器件及其发光机理

利用5,6,11,12-tetraphenylnaphthacene(Rubrene)超薄层制备了一种蓝光有机电致发光器件(OLED),器件结构为ITO/N,N'-diphenyl-N,N'-bis(1-naphthyl)-(1,18-biphenyl)-4,4'-diamine(NPB)(50nm)/2,9-d...