蓝光磷光微腔有机电致发光器件特性的研究

使用典型蓝色磷光材料Firpic作为磷光金属微腔 有机电致发光器件(OLED)的发光层, 以高反射的Al膜作为阴极顶电极和半透明的Al膜作为阳极底电极,其结构为 Glass/Al(15nm)/MoO₃(30nm)/NPB(40nm)/mCP:Firpic(30nm,x%)/BCP(10nm)/Alq(20nm)/LiF (1nm)/Al(100nm),x%为Firpic的掺杂 质量分数,分别为4%、6%、10%、12%和14%。实验 制备了不同的OLED,比较了测量角度和不同掺杂浓度对OLED发光特性的影响。结 果显示,对发光面积为0.8cm²的器件,测量角度的不同导致蓝光 辐射波长蓝移,色坐标发 生变化,器件的510nm和472nm两个峰值变化 不相同,随着角度的增大, 较大的峰值不断衰减,而较小的峰值不断增强;并且,当掺杂浓度为12%时,OLED得 到最好的发光性能,12V电压驱动下有最大亮度18870cd/m²,说明此时的主客体间能量转移最充分。     

High efficiency blue PhOLEDs using spiro-annulated triphenylamine/fluorene hybrids as host materials with high triplet energy,high HOMO level and high Tg

Two spiro-annulated triphenylamine/fluorene oligomers, namely 4′-(9,9′-spirobifluoren-4-yl)-10-phenyl-10H-spiro[acridine-9,9′-fluorene] (NSF-SF), and 4,4′-di(spiro(triphenylamine-9,9′-fluorene)-2-yl)-spiro(triphenylamine-9,9′-fluorene) (NSF-NSF), are designed and synthesized. Their thermal, electrochemical and photophysical properties were investigated. The introduction of spiro-annulated triphenylamine moieties assurances the high HOMO energy levels of NSF-NSF and NSF-SF at −5.31 eV and −5.33 eV, respectively, which accordingly facilitates the hole injection from nearby hole-transporting layer. Meanwhile, the perpendicular arrangement of the spiro-conformation and the full ortho-linkage effectively prevents the extension of the π-conjugation and consequently guarantees their high triplet energies of 2.83 eV. Phosphorescent organic light-emitting devices (PhOLEDs) with the configurations of ITO/MoO₃/TAPC/EML/TmPyPB/LiF/Al were fabricated by using the two compounds as host materials and bis[2-(4′,6′-difluorophenyl)pyridinato-N,C^2′]iridium(III) picolate (FIrpic) as the dopant. The turn-on voltage of the device B based on NSF-NSF was 2.8 V. Simultaneously, the device exhibited excellent performance with the maximum current efficiency of 41 cd A⁻¹, the maximum power efficiency of 42 lm W⁻¹ and the maximum external quantum efficiency (EQE) of 19.1%. At a high brightness of 1000 cd m⁻², the device remained EQE of 16.2% and the roll-off value of external quantum efficiency is 15%.     

Host-Guest Chemistry of Chiral MOFs for Multicolor Circularly Polarized Luminescence Including Room Temperature Phosphorescence

Exploiting the chirality transfer and amplification in the hierarchical chiral systems by the visible and accurate structures is still a challenge. Herein, a pair of homochiral metal-organic frameworks (MOFs) DCF-12 and LCF-12 with high rigidity and high porosity are synthesized via reticular chemistry. Interestingly, these two enantiomers can act as nano-containers, in which four chromophores, covering acridine, pyrene, 9,10-Bis(phenylvinyl) anthracene (BPEA), and coronene can be introduced by in situ encapsulation. Importantly, the precise single crystal structures of all guest-loaded MOFs by X-ray diffraction technique can be obtained smoothly. It not only clearly reveals the chirality transfer from chiral host framework to achiral guest emitters through space chirality transfer, but also circularly polarized luminescence can be achieved and modulated through the synergistic effect. Extraordinarily, both pyrene@DCF-12 and pyrene@LCF-12 exhibit fascinating multi-color tunable room temperature phosphorescence (RTP) and dynamic circularly polarized luminescence. Besides, the RTP quantum yields of pyrene@DCF-12 and pyrene@LCD-12 are high up to 75.39% and 73.43%, which exceeds most of that of RTP materials. These results demonstrate that chiral MOFs can serve as an accurate platform to investigate the mechanism of chirality transfer and amplification and to prompt the development of CPL-active materials.     

Long Persistent Luminescence from Metal–Organic Compounds: State of the Art

The excited-state tuning of luminescent metal–organic compounds has made great progress in the fields of optical imaging, photocatalysis, photodynamic therapy, light-emitting devices, sensors, and so on. Although metal–organic compounds with high luminescence efficiency can be realized via enhanced molecular rigidity and heavy-atom effect, their corresponding luminescence lifetimes are still limited on the order of a nanosecond to a millisecond, owing to the inherent competition between luminous efficiency and lifetime. Therefore, the advanced applications (i.e., persistent afterglow imaging, information security, anti-counterfeiting, and smart materials, among others) related with long persistent luminescence (LPL, typically with the excited-state lifetime larger than millisecond) are seriously hindered. This review gives a timely and systematic summary of metal–organic compounds for realizing room-temperature phosphorescence (RTP)-type and thermally activated delayed fluorescence (TADF)-type LPL during last few years. Particularly, based on the perspectives of time, space, and energy dimensions, fundamental materials design and coordination assembly are systematically described for the first time. Moreover, the internal and external factors of influencing the LPL properties in terms of luminescence efficiency, lifetime, and color are illustrated. Last but not least, perspectives and challenges are also discussed for developing LPL from metal–organic compounds.     

稀土氯化物溶液掺杂BaTiO3基PTC陶瓷性能研究

采用稀土氯化物(YCl3、LaCl3)溶液作为施主掺杂剂,在1350℃空气气氛下烧结制备一系列BaTiO3陶瓷样品。借助XRD、XRF等手段,研究了氯化物溶液掺杂对BaTiO3基PTC陶瓷性能的影响。结果显示,YCl3掺杂样品的最低室温电阻率为17?·cm、LaCl3掺杂的为47?·cm,且样品都具有一定的PTC效应。室温电阻率大幅降低的原因,是引入的Cl元素有一部分能进入晶格取代O位起施主作用。     

常温常压下氮氢气体放电合成氨的研究

室温常压下,储存在高压钢瓶中的氮,氢气体,流经石英玻璃气套,石英玻璃气套安放在一对圆柱面电极中间,两圆柱面电极与交流电源相连接,电源的输出电压为８￣１５ｋＶ,频率为５０Ｈｚ￣２０ｋＨｚ。石英玻璃气套中的氮氢气体被高电场强度的交流电场所激活,具有了化学活泼性。常温常压下的气体分子间发生频繁的碰撞可引发化学反应。     

1.3414μm Nd:YAlO3激光泵浦的室温中红外Co:MgF2激光器

报道了1.3414μmNd:YAlO3激光端面泵浦的室温2.1000μmCo:MgF2脉冲激光的实验结果,得到了279.4mJ能量输出,器件斜率效率达23%,阈值能量为125mJ.     

Ultrasmall Phosphorescent Polymer Dots for Ratiometric Oxygen Sensing and Photodynamic Cancer Therapy

A series of semiconducting polymer dots (Pdots) composed of phosphorescent Ir(III) complexes and polyfluorene units in the main polymer chains are designed, synthesized, and applied in ratiometric oxygen sensing and photodynamic cancer therapy. The ultrasmall Pdots with particle size less than 10 nm are fabricated in aqueous solution on account of amphiphilic nature of the polymers. The Pdots possess fine photostability, biocompatibility, and efficient energy transfer from the polymer main chain to the Ir(III) complex. By utilizing the excited‐state energy transfer from phosphorescent Pdots to the ground state molecular oxygen, these Pdots are applied in the optical sensing of oxygen with ratiometric and naked‐eye detection as well as high sensitivity in aqueous solution. The Pdots also show low cytotoxicity and can pass across the cell membrane to enter into the cytoplasm. The singlet oxygen photo‐generated from the Pdots under irradiation at 488 nm can effectively induce the apoptosis and death of tumor cells for photodynamic cancer therapy in vitro.     

高效暖白光器件的廉价制备及其相关材料研究

低色温光源由于其对抗黑变激素具有较低的抑制作用而成为生理友好照明的首选。同时,高的能量效率对于节能也至关重要。本课题采用温和的溶液旋涂方法分别制备了含互补色、三基色和四基色磷光染料的单层有机白光二极管(WOLED)。经过优化WOLED的结构,实现了宽亮度范围内100~10 000cd/m2的低色温(low-CCT)白光发射。CCT低至2 500K以下、显示指数(CRI)高达到83、电流效率在亮度为1 000cd/m2时达到了17.8cd/A,与传统的白炽灯功效相当。高发光性能、廉价制备成本及生理友好的特性表明,本工作制备的器件是益于人类健康的照明光源尤其是夜间照明光源的理想选择。     

Enhancing Phosphorescence and Electrophosphorescence Efficiency of Cyclometalated Pt(II) Compounds with Triarylboron

A synthetic strategy for the preparation of cyclometalated platinum(II) acetylacetonate (acac) complexes functionalized with triarylboron is achieved. This method is used to synthesize a series of triarylboron‐functionalized phosphorescent Pt(acac) compounds, which are characterized by NMR spectroscopy, X‐ray crystallography, and theoretical calculations. These complexes exhibit a range of bright phosphorescent colors spanning the green to red region of the visible spectrum (λ_max = ～520–650 nm) in solution and the solid state. Functionalization with a triarylboron group leads to significant enhancement in quantum yield for several of these complexes relative to the non‐borylated Pt(II) parent chromophores, which may be attributed to the increased mixing of ¹MLCT and ³LC states. The phosphorescent enhancement, electron transport capabilities, and steric bulkiness offered by the triarylboron group can be used to significantly enhance the performance of electrophosphorescent devices based on Pt(II) emitters. A high efficiency green electrophosphorescent device is fabricated with a maximum external quantum efficiency of 8.9%, luminance efficiency of 34.5 cd A^?1, and power efficiency of 29.8 lm W^?1, giving significantly improved performance over control devices in which the Pt(II) emitter lacks the boron functionality.