荧光/磷光混合型白光有机发光二极管的研究

白光有机发光二极管（white organic light-emitting diodes,WOLEDs）在全色显示、固态照明以及背光源等领域有巨大的应用前景,其研究备受关注.其中,荧光/磷光混合型WOLEDs因兼具荧光材料的长寿命和磷光材料的高效率,被认为是目前最有希望实现照明应用的器件结构.荧光/磷光混合型WOLEDs最重要的问题是要解决荧光材料的单线态激子和磷光材料的三线态激子的协同发光.为了避免单线态激子和三线态激子的相互猝灭问题,必须设计有效的器件结构.本文以两种不同三线态能级的蓝光荧光材料为研究对象,介绍了不同高性能荧光/磷光混合型WOLEDs的结构设计与性能.研究表明,载流子传输平衡的高效结构设计和激子分布宽范围内的有效调控是实现高性能荧光/磷光混合型WOLEDs的关键.     

普鲁士蓝/壳聚糖杂化膜修饰氧化锌球腔阵列/氧化铟锡电极制备及应用

用Langmuir-Blodgett技术制成了附着聚苯乙烯小球的氧化铟锡(InSnO)模板。将此模板水平置于由硝酸锌及柠檬酸组成的前驱体溶胶中,用溶胶-凝胶法制得氧化锌球腔阵列/氧化铟锡电极。采用电沉积法得到普鲁士蓝/壳聚糖杂化膜修饰的氧化锌球腔阵列/氧化铟锡电极。该电极在pH 7.0～8.0的溶液中具有良好的电化学活性,过氧化氢浓度在7.67×10-7～4.72×10-4mol.L-1范围内与相应的电流响应值呈线性关系,检出限(3S/N)为2.4×10-7mol.L-1。测定2.0×10-5mol.L-1过氧化氢溶液时,其相对标准偏差(n=10)为3.8%。     

氧化铟锡(ITO)自组装修饰及其对有机电致发光器件性能的影响

设计合成了一种新型的有机硅氧烷Cz-Si,并将其用于ITO自组装修饰。制备的Cz-Si具有较好的稳定性,可以在空气中对ITO进行自组装修饰,实验操作简单。为考察ITO自组装修饰对有机电致发光器件性能的影响,分别以修饰后的ITO(ITO/SAM)及不修饰的ITO(unmodified)作阳极,制备了一系列有机电致发光器件ITO/SAM(or unmodified)/NPB(40~50 nm)/Alq₃(60 nm)/LiF(1.0 nm)/Al。实验结果表明,ITO自组装修饰后器件性能可以得到显著提升,研究认为这与其调控ITO/有机层界面的电子能级、粗糙度以及界面一致性有关。     

氧化铟锡(ITO)自组装修饰及其对有机电致发光器件性能的影响

设计合成了一种新型的有机硅氧烷Cz-Si,并将其用于ITO自组装修饰。制备的Cz-Si具有较好的稳定性,可以在空气中对ITO进行自组装修饰,实验操作简单。为考察ITO自组装修饰对有机电致发光器件性能的影响,分别以修饰后的ITO(ITO/SAM)及不修饰的ITO(unmodified)作阳极,制备了一系列有机电致发光器件ITO/SAM(orunmodified)/NPB(40~50nm)/Alq₃(60nm)/LiF(1.0nm)/Al。实验结果表明,ITO自组装修饰后器件性能可以得到显著提升,研究认为这与其调控ITO/有机层界面的电子能级、粗糙度以及界面一致性有关。     

Atomic Layer Deposition of Ternary Indium/Tin/Aluminum Oxide Thin Films,Their Characterization and Transistor Performance under Illumination.

Multilayered heterostructures comprising of In₂O₃, SnO₂, and Al₂O₃ were studied for their application in thin-film transistors (TFT). The compositional influence of tin oxide on the properties of the thin-film, as well as on the TFT characteristics is investigated. The heterostructures are fabricated by atomic layer deposition (ALD) at 200 °C, employing trimethylindium (TMI), tetrakis(dimethylamino)tin (TDMASn), trimethylaluminum (TMA), and water as precursors. After post-deposition annealing at 400 °C the thin-films are found to be amorphous, however, they show a discrete layer structure of the individual oxides of uniform film thickness and high optical transparency in the visible region. Incorporation of only two monolayers of Al₂O₃ in the active semiconducting layer the formation of oxygen vacancies can be effectively suppressed, resulting in an improved semiconducting and switching behavior. The heterostacks comprising of In₂O₃/SnO₂/Al₂O₃ are incorporated into TFT devices, exhibiting a saturation field-effect mobility (μ_sat) of 2.0 cm² ⋅ V⁻¹ s⁻¹, a threshold-voltage (V_th) of 8.6 V, a high current on/off ratio (I_On/I_Off) of 1.0×10⁷, and a subthreshold swing (SS) of 485 mV ⋅ dec⁻¹. The stability of the TFT under illumination is also altered to a significant extent. A change in the transfer characteristic towards conductive behavior is evident when illuminated with light of an energy of 3.1 eV (400 nm).     

基于面式-三(2-(4-三氟甲基苯基)吡啶)合铱配合物为发光中心的高效绿光有机电致发光器件

用经典的方法合成了面式-三(2-(4-三氟甲基苯基)吡啶)合铱配合物(fac-Ir(tfmppy)3),并得到了其晶体结构。在CH2Cl2溶液中Ir(tfmppy)3的发射光谱显示出了峰值位于525 nm的π→π*跃迁吸收以及金属到配体电荷转移(MLCT)吸收,色坐标(CIE)为(0.31,0.62),量子效率计算为4.59%(以Ru(bpy)3]Cl2为参照)。以Ir(tfmppy)3为发光中心,制备并研究了有机电致发光器件:ITO/TAPC(60 nm)/Ir(tfmppy)3(x%)∶mCP(30 nm)/TPBi(60 nm)/LiF(1 nm)/Al(100 nm)。4%掺杂浓度的器件在4 197 cd·m-2的亮度下显示的最大电流效率为33.95 cd·A-1,在12.7 V时的最大亮度为43 612 cd·m-2,色坐标(CIE)为(0.31,0.61)。利用瞬态电致发光法(transient electroluminescence(TEL))、在1 300(V·cm-1)1/2的电场强度下Ir(tfmppy)3配合物的电子迁移率测定为4.24×10-6cm2·(V·s)-1。非常接近于常用的电子传输材料八羟基喹啉铝(Alq3)的电子迁移率。     

基于面式-三(2-(4-三氟甲基苯基)吡啶)合铱配合物为发光中心的高效绿光有机电致发光器件

用经典的方法合成了面式-三(2-(4-三氟甲基苯基)吡啶)合铱配合物(fac-Ir(tfmppy)₃), 并得到了其晶体结构。在CH₂Cl₂溶液中Ir(tfmppy)₃的发射光谱显示出了峰值位于525 nm的π→π^*跃迁吸收以及金属到配体电荷转移(MLCT)吸收, 色坐标(CIE)为(0.31, 0.62), 量子效率计算为4.59%(以Ru(bpy)₃]Cl₂为参照)。以Ir(tfmppy)₃为发光中心, 制备并研究了有机电致发光器件:ITO/TAPC (60 nm)/Ir(tfmppy)₃ (x%):mCP (30 nm)/TPBi (60 nm)/LiF (1 nm)/Al (100 nm)。4%掺杂浓度的器件在4 197 cd·m^-2的亮度下显示的最大电流效率为33.95 cd·A^-1, 在12.7 V时的最大亮度为43 612 cd·m^-2, 色坐标(CIE)为(0.31, 0.61)。利用瞬态电致发光法(transient electroluminescence (EL))、在1 300 (V·cm^-1)^1/2的电场强度下Ir(tfmppy)₃配合物的电子迁移率测定为4.24×10^-6 cm²·(V·s)^-1。非常接近于常用的电子传输材料八羟基喹啉铝(Alq₃)的电子迁移率。     

Effective Host Materials for Blue/White Organic Light‐Emitting Diodes by Utilizing the Twisted Conjugation Structure in 10‐Phenyl‐9,10‐Dihydroacridine Block

Two new 10‐phenyl‐9,10‐dihydroacridine derivatives attached by dibenzothiophene (DBT) and dibenzofuran (DBF) were synthesized. The influence of the substituents of these materials was studied by theoretical calculations (DFT calculation) and experimental measurements. Owing to the twisted N‐phenyl ring, both molecules possess sufficiently high triplet energies and are suitable as hosts for phosphorescent organic light‐emitting diodes. To evaluate the electroluminescent (EL) performance of these materials, FIrpic‐based blue PHOLEDs and two‐color white PHOLEDs (FIrpic and PO‐01 as the dopants) were fabricated using the common device structures. High external quantum efficiencies (EQE) of 21.1 % and 20.9 % for FIrpic‐based blue PHOLEDs were achieved by FPhAc and TPhAc, respectively. The white device based on the host FPhAc achieved a higher performance, with a maximum EQE of 24.7 % than the device with TPhAc as host material.     

Selective Oxidation of CO in Excess H2 over Ru/Al2O3 Catalysts Modified with Metal Oxide

The Ru/Al_2O_3 catalysts modified with metal oxide(K_2O and La_2O_3)were prepared via incipient wetness impregnation method from RuCl_3·nH_2O mixed with nitrate loading on Al_2O3 support. The activity of catalysts was evaluated under simulative conditions for the preferential oxidation of CO (CO-PROX)from the hydrogen-rich gas streams produced by reforming gas,and the performances of catalysts were investigated by XRD and TPR.The results showed that the activity temperature of the modified catalysts Ru-K_2O/Al_2O3 and Ru-La_2O_3/Al_2O_3 were lowered approximately 30℃compared with pure Ru/Al_2O_3,and the activity temperature range was widened.The conversion of CO on Ru-K_2O/Al_2O_3 and Ru-La_2O_3/Al_2O_3 was above 99% at 140-160℃,suitable to remove CO in a hydrogen-rich gas and the selectivity of Ru-La_2O_3/Al_2O_3 was higher than that of Ru-K_2O/Al_2O_3 in the active temperature range. Slight methanation reaction was detected at 220℃and above.     

Coating of Al2O3 on layered Li(Mn1/3Ni1/3Co1/3)O2 using CO2 as green precipitant and their improved electrochemical performance for lithium ion batteries

Li(Mn_1/3Ni_1/3Co_1/3)O₂ cathode materials were fabricated by a hydroxide precursor method. Al₂O₃ was coated on the surface of the Li(Mn_1/3Ni_1/3Co_1/3)O₂ through a simple and effective one-step electrostatic self-assembly method. In the coating process, a NHCO₃-H₂CO₃ buffer was formed spontaneously when CO₂ was introduced into the NaAlO₂ solution. Compared with bare Li(Mn_1/3M_1/3Co_1/3)O₂, the surface-modified samples exhibited better cycling performance, rate capability and rate capability retention. The Al₂O₃-coated Li(Mn_1/3Ni_1/3Co_1/3)O₂ electrodes delivered a discharge capacity of about 115 mAh·g^?1 at 2 A·g^?1, but only 84 mAh·g^?1 for the bare one. The capacity retention of the Al₂O₃-coated Li(Mn_1/3Ni_1/3Co_1/3)O₂ was 90.7% after 50 cycles, about 30% higher than that of the pristine one.