芴类衍生物有机电致发光器件中的激基复合物

利用紫外-可见光吸收光谱和荧光发光(PL)光谱,研究了新型芴类小分子材料2,3-bis(9,9-dihexyl-9H-flu-oren-2-yl)-6,7-difluoroquinoxaline(F2Py)的本征光谱特性,并制备了基于F2Py的有机电致发光器件(OLEDs),讨论了器件的电致发光(EL)光谱。结果表明,F2Py在溶液状态下的本征PL峰值位于452 nm,在薄膜状态下的本征PL峰值位于448 nm,而F2Py与NPB的混合物的PL发光峰在544 nm。在器件的EL光谱中,观察到了位于530~550 nm范围的激基复合物发光峰,以及来自F2Py与NPB激子发光的共同作用形成的位于430nm左右的肩峰。当F2Py层厚度为50 nm时,器件的启亮电压为17 V,最高亮度为58 cd/m2;而当F2Py厚度为20 nm并加入了Alq3(10 nm)做电子传输层(ETL)时,器件启亮电压为8 V,最高亮度为5030 cd/m2,EL性能大大提高。     

电子传输层厚度对LiBq4蓝色有机电致发光器件的影响

制备了以LiBq4为发光层,结构为ITO/CuPc/TPD/LiBq4/Alq3/LiF/Al的器件.器件的电致发光(EL)光谱与LiBq4薄膜的光致发光(PL)光谱相同,峰值波长均为492nm.改变电子传输层Alq3的厚度时,器件的电流-电压特性及发光光谱随之发生变化,当电子传输层的厚度为5nm时,既可以避免电子传输层的发光,又可以降低器件的工作电压.     

利用BCP空穴阻挡层改善白光OLED色度的研究

分别将具有空穴传输特性的蓝光材料pNPB和具有电子传输特性的蓝绿光材料Zn（BTZ）2作为2层发光层，将荧光染料rubrene掺入β-NPB中，在发光层间引入5nm具有空穴阻挡作用的BCP层，制备了一种ITO／PVK：β-NPB：rubrene／BCP／Zn（BTZ）。／Mg：Ag/Ag结构白色有机电致发光器件（OLED）。该器件在5V电压下起亮；18V电压下亮度和色坐标分别为1600cd／m^2和（0．31，0．33），最大外量子效率为0．21％。其色度比不含或含较厚BCP层（〉5nm）的器件均有了很大的改善，并从能带结构和空穴阻挡层厚度2方面探讨了色度改善的原因。     

BCP的厚度对OLED性能的影响

设计了一种有机电致发光器件（OLED）结构：ITO／NPB（50nm）／BCP（x）／Alq3（50mm）／LiF（0．5mm）／Al（120nm）。在实验中改变BCP的厚度,调整电子和空穴的注入平衡,控制发光层（EML）。研究发现：当BCP的厚度为0nm时,器件为典型的双层OLED结构,光谱为绿色的Alq3特征光谱;当厚度为8nm或8nm以上时,发光区完全基于NPB层,器件为蓝色发光;当厚度在1nm到8nm时,NPB层和Alq3层对发光都有贡献,EL谱线包括蓝光发射和绿光发射。BCP层起到了调节载流子复合区域和改变器件发光颜色的作用,因此控制BCP的厚度可以改善器件的性能。     

有机无机复合膜发光器件的研究

针对聚合物电致发光（EL）材料缺乏可用的电子型聚合物半导体材料的现状，采用无机电子型半导体材料ZnO：Zn与空穴型聚合物材料poly（2，5bis（dodecyloxy）-phenylenevinylene）（PDDOPV）成功制备了结构为ITO／PDDOPV／ZnO：Zn／Al的有机／无机复合膜双层器件。复合膜器件的发光效率与亮度比单层器件提高了1个数量级以上，而复合膜的电流是单层器件的0．5倍。而且，聚合物／无机物复合膜器件的发光颜色随电压的增加而蓝移，其光致发光（PL）光谱也随激发波长的改变而改变，有可能形成了新的发光基团。     

基于TPD:PO-T2T的黄光激基复合物发光性能研究

通过多源有机分子气相沉积系统(LN-386SA)制备结构为ITO/HAT-CN/TPD/TPD:PO-T2T/PO-T2T(x=10,20,30,40,50,60,70 nm)/LiF/Al的有机发光器件,研究了电子传输层(PO-T2T)厚度对TPD:PO-T2T黄光激基复合物发光性能的影响。PO-T2T厚度对其电致发光(electroluminescence, EL)光谱几乎没有影响,但对电流密度(current density, CD)、亮度、效率等性能有较大影响。由于金属铝扩散至发光层中会形成淬灭中心降低发光效率,当PO-T2T越厚时,扩散至发光层的铝原子越少,因此发光效率随PO-T2T厚度增加而增加。当PO-T2T厚度为70 nm时,获得最大电流效率(current efficiency, CE)和功率效率(power efficiency, PE),分别为2.16 cd/A、2.12 lm/W。此外,瞬态EL性能表明TPD:PO-T2T的发光来自TPD和PO-T2T分别对载流子的直接捕获,没有发光瞬时过冲或者深陷阱中载流子逃逸复合发光的现象。     

基于Zn(Meq)_2为发光和主体材料OLEDs性能的研究

以2-甲基-8-羟基喹啉配体和ZnSO_4·7H_2O合成了有机金属配合物Zn(Meq)_2,并开展了材料的光电特性研究。当双层器件结构为ITO/NPB/Zn(Meq)_2/LiF/Al时,实现了绿光发射,EL峰位位于542 nm,最大亮度和效率分别为7 429 cd/m~2和1.80 cd/A。而当掺杂器件结构为ITO/NPB/Zn(Meq)_2:DCJTB/Alq_3/Li F/Al时,实现了红橙光发射,EL峰位位于580 nm,最大亮度和效率分别为6 075 cd/m~2和1.02 cd/A。结合器件结构和性能,讨论了相关工作机制。     

一种新结构中ZnSe薄膜电致发光特性研究

用电子束蒸发的方法制备了一种新的ITO／SiO2／ZnSe／SiO2／Al薄膜电致(TFEL)发光器件。在交流电压驱动下,其有2个发光峰,分别位于466nm和560nm。通过研究器件(PL)激发(PLE)谱、光致发光、EL发光以及EL发光强度随驱动电压和频率的变化发现,器件的发光来源于ZnSe的带边发射和自激活发光中心。器件的发光机理与一般的无机电致发光有所不同。这里,SiO2作为电子加速层,ZnSe作为发光层,电子在SiO2层中的高电场作用下被加速到很高的能量,然后直接碰撞激发ZnSe分子使其发光。这种发光现象被称为固态类阴极发光。     

非对称绝缘层无机EL显示器件的研究

非对称绝缘层无机EL显示器件是一种新颖的器件结构。成功制备了一批ZnS：Mn器件,其下介质层为厚100-200nm的SrTiO3（ST）或Ba0．5Sr0．5TiO3（BST）或Ta2O5薄膜,上介质层为厚600～1100nm的Ta2O5或ST／Ta2O5或HfO2／Ta2O5／Al2O3薄膜。发现以ST／Ta2O5为上介质层的器件具有适当的阈值电压、较高的L50和较陡的L—V曲线,以HfO2／Ta2O5／Al2O3为上介质层的器件具有较高的可靠性。     

发光层厚度对双层有机EL器件ITO/PPV/Alq_3/Al发光特性的影响

制备出一组双层有机EL器件ITO／PPV／Alq3／Al，测试并分析了各层厚度不同时器件的光电性能．     

Gaq3有机薄膜电致发光器件

首次报道了采用８－羟基喹啉镓螯合物作为发光层制备有机薄膜电致发光器件，器件的结构为：ＩＴＯ导电玻璃／ＴＰＤ／Ｇａｑ３／Ａｌ。研究了Ｇａｑ３薄膜的光致发光和器件的电致发光机理，同时测量和研究了器件的电流密度－－电压（Ｊ－Ｖ）特性和发光亮度－电压（Ｂ－Ｖ）特性。结果表明器件的电致发光峰值波长为５４０ｎｍ，在２０Ｖ直流电压驱动下的最大发光亮度约２５００ｃｄ／ｍ＾２明显高于上同结构和工艺参数制备的Ａｌｑ３     

含Sc(DBM)3bath的有机发光二极管的界面激基复合物发光

报道了一种含Sc(DBM)3bath的有机发光二极管(OLED)的界面激基复合物发光,器件结构为ITO/TPD/Sc(DBM)3bath/LiF/Al,其中TPD和Sc(DBM)3bath分别为空穴和电子传输材料。这种电致发光(EL)发射主峰位于597nm,最高亮度接近200cd/m2,这种发射来自于TPD和Sc(DBM)3bath界面处两个功能层的相互作用产生的激基复合物。同时该LED在紫外光照射下还表现出明显的光伏特性。     

The electroluminescent investigation of double layer Eu-complex organic electronic luminescence diodes

Double layer organic electronic luminescence diodes (OLEDs) based on europium(dibenzoylmethanato)₃monophenanthroline [Eu(DBM)₃bath], ITO/N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD)/Eu(DBM)₃bath/LiF/Al have been fabricated. With increasing the thickness of hole transporting layer, the maximum EL efficiency was increased, and the EL efficiency of 10 cd/A was achieved when the thickness of TPD layer was 80 nm; however, at high current density, the EL efficiency of all devices was decreased drastically. Besides, the evolution of EL emission spectra with increasing operating voltage was found, the mechanisms of the symmetry around the ion improved and the annihilation of excited state of Eu(DBM)₃bath were discussed in explaining this phenomenon.     

Synthesis and luminescence properties of lithium,zinc and scandium 1-(2-pyridyl)naphtholates

1-(2-Pyridyl)naphth-2-ol (pynH) was synthesized from 2-bromopyridine and 1-bromo-2-hydroxynaphthalene and structurally characterized. This ligand and the known 2-(2-pyridyl)phenol (ppH) ligand were reacted with LiN(SiMe₃)₂, ZnEt₂ and Sc[N(SiMe₃)₂]₃ to prepare the new luminescent complexes Li(pp), Li(pyn), Zn(pyn)₂, Sc(pp)₃, Sc(pyn)₃ and known Zn(pp)₂. Photoluminescent (PL) spectra of the compounds contained a single broad band with a maximum at 447–473 nm. The OLED devices with a configuration of ITO/TPD/complex/Bath/Yb gave blue–green emission. The emission spectra of these devices resembled the PL spectra; however, the bands of electroluminescence (EL) were shifted 20–40 nm to the long-wavelength side. A maximum current efficiency 15.3 cd/A and a power efficiency 8.12 lm/W at 100 cd/m² were measured for the device with the zinc luminophore Zn(pp)₂, whereas the highest luminance of 8300 cd/m² at 22.5 V was observed with the device with the scandium complex Sc(pp)₃. DFT calculations showed that the latter complex exhibited the lowest HOMO and the highest LUMO energy levels compared with the other investigated compounds. The calculated trends with respect to the influence of the metal and the ligand on the LUMO–HOMO gap agree well with the shifts of the electronic transitions observed in the PL spectra of the complexes.     

Effect of different processing methods for the hole transporting layer on the performance of double layer organic light-emitting devices

The hole transporting layer （HTL） of organic light-emitting device （OLED） was processed by vacuum deposition and spin coating method, respectively, where N,N＇-biphenyl-N, N＇-bis（3-methylphenyl）- 1, l＇-biphenyl-4,4＇ -diamine （TPD） and poly （vinylcarbazole） （PVK） acted as the hole-transport materials. Tris-（8-hydroxyquinoline）- aluminum （Alq3） was utilized as both the light-emitting layer and the electron transporting layer. The basic structure of the device cell was： indium-tin-oxide （1TO）/PVK ： TPD/Alq3/Mg：Ag. The electroluminescent （EL） characteristics of devices were characterized. The results showed that the peak of EL spectra was located at 530 nm, which conformed to the characterizing spectrum of Alq3. Compared with using vacuum deposition method, the green emission with a maximum luminance up to 26135 cd/m2 could be achieved at a drive voltage of 15 V by selecting proper solvent using spin-coating technique, and its maximum lumi nance efficiency was 2.56 lm/W at a drive voltage of 5.5 V.     

富Si的SiN薄膜光致发光及电致发光研究

采用等离子体化学气相沉积法(PECVD)制备了三种不同化学计量比的富Si的SiN薄膜,并对其光致发光及电致发光性能进行了研究.研究发现,随着Si含量的增加,薄膜的光致发光峰位从460 nm红移到610 nm,且半高宽不断增加;而薄膜的电致发光峰位并没有随着Si含量的改变而变化,始终处于600 nm附近,这主要是由于富Si的SiN薄膜的光致发光与电致发光的机理是不同的.光致发光来源于SiN薄膜缺陷态能级之间辐射复合,而电致发光则是由注入的裁流子先迟豫到较低的缺陷态能级,然后经过辐射复合而得到.     

The effect of gamma irradiation and forward bias on the 76 K electroluminescence spectrum of GaP:Zn,O

Both the effects of gamma irradiation and high-current forward bias on the low temperature electroluminescence (EL) spectra of GaP:Zn,O light emitting diodes (LEDs) have been studied by measuring constant current (1 mA) 76 K EL spectra below 1000 nm. The LEDs were divided into two sets: a control set which was subjected only to forward bias, and a set exposed to gamma irradiation and forward bias. The EL spectra reveal the growth of sharp, bound exciton emission bands (Z lines) in the range 580 nm to 620 nm following extended high current bias at 300 K of irradiated LEDs and, more weakly, in control LEDs which show pre-bias evidence of these lines. The emergence of these lines is tenatively associated with the recombination-enhanced motion of a defect, possibly the Zn interstitial, which can be introduced by irradiation and is sometimes present in unirradiated LEDs. This article sponsored by the U. S. Department of Energy (DOE) under Contract No. DE-AC04-76-DP00789. A United States Department of Energy Facility.     

8-羟基喹啉锂蓝色有机电致发光器件

合成了蓝色有机薄膜电致发光材料8-羟基喹啉锂(Liq),8-羟基喹啉锂薄膜的PL光谱峰位于475nm^2分析了8-羟基喹啉锂发射光谱蓝移的原因^2制备了两种结构的蓝色发光器件,其最高亮度分别为1200cd／m^2和2000cd／m^2,EL峰位于490nm^2用能级图比较和分析了两种器件的特性。