发光二极管完整版讲解.docx

1、发光二极管完整版讲解异质结文献翻译-The Second Group第二组组员信息表姓名学号班级李周（组长）5120145153光信1402班蔡玉栋5120143161光信1402班吴桃星5120142455光信1402班林勇5120145174光信1402班王世海5120145162光信1402班孙春元5120143160光信1401班夏庆尧5120145167光信1401班High-Resolution Patterns of Quantum Dots Formed by Electrohydrodynamic Jet Printing for Light-Emitting Diodes电

2、子喷墨打印形成高分辨率量子点阵的发光二极管应用Department of Materials Science and Engineering, Beckman Institute for Advanced Science and Technology, Frederick Seitz Materials Research Laboratory, University of Illinois at UrbanaChampaign, Urbana, Illinois 61801, United States Departments of Materials Science and Engineer

3、ing, Nanotechnology Research Center (ERNAM) Erciyes University, Kayseri, 38039, Turkey材料科学与工程系，贝克曼先进科学和技术研究所，Frederick Seitz Materials研究实验室， Illinois大学Urbana-Champaign分校，Illinois 61801，美国材料科学与工程系，纳米技术研究中心（ERNAM）Erciyes大学，Kayseri，38039，土耳其 支持信息ABSTRACT: Here we demonstrate materials and operating con

4、ditions that allow for high-resolution printing of layers of quantum dots (QDs) with precise control over thickness and submicron lateral resolution and capabilities for use as active layers of QD light-emitting diodes (LEDs). The shapes and thicknesses of the QD patterns exhibit systematic dependen

5、ce on the dimensions of the printing nozzle and the ink composition in ways that allow nearly arbitrary, systematic control when exploited in a fully automated printing tool. Homogeneous arrays of patterns of QDs serve as the basis for corresponding arrays of QD LEDs that exhibit excellent performan

6、ce. Sequential printing of dierent types of QDs in a multilayer stack or in an interdigitated geometry provides strategies for continuous tuning of the eective, overall emission wavelengths of the resulting QD LEDs. This strategy is useful to ecient, additive use of QDs for wide ranging types of ele

7、ctronic and optoelectronic devices. 摘要：在这里，我们演示了高分辨率打印多层量子点所需的材料和操作条件。打印过程中需要精确控制量子点的厚度和亚微米横向分辨率及其性能。打印出的量子点可被用作发光二极管的有源层。当用于全自动印刷工具时，以几乎允许任意系统的控制方式，在打印喷嘴的尺寸和油墨组合方面，量子点模式的形状和厚度呈现出具有系统依赖性的特点。量子点模式的均匀阵列作为相应量子点LED阵列，表现出优异的性能。在多层堆叠或交叉几何学中，不同类型的量子点的顺序打印，为所得到的量子点发光二极管的全部有效的发射波长，提供持续的调整策略。对于电子和光电器件的宽范围类型的有

8、效的附加应用，这种策略是有用的。KEYWORDS: Electrohydrodynamic jet printing, nanopatterning, quantum dots, light-emitting diode, electroluminescence 关键词：电流体喷射印花，纳米，量子点，发光二极管，电致发光Colloidal quantum dots (QDs) are nanoscale crystals of semiconducting materials that can be synthesized and processed using bulk solution p

9、hase techniques.17 The sizedependent electrical/optical properties of QDs can be exploited in unusual classes of electronic and optoelectronic devices with potential for use in solid-state lighting,8,9 information displays,1015 imaging detectors, and other systems.16 Quantumdot based light-emitting

10、diodes (QD LEDs) are of particular interest due to their wide-range color tunability, high brightness, and narrow emission bandwidth.1719 Challenges remain, however, in achieving optimized control of charge transport/ light emission and in forming the necessary multilayer device structures.20,21 Res

11、earch over the last several years has led to significant progress on the former set of topics.22 Approaches to address the latter include conventional ink jet printing,23 advanced techniques of transfer printing12,24,25 and, in initial feasibility demonstrations, dip pen nanolithography.2628 The aim

12、 is to enable patterning/stacking of red-green-blue (RGB) QDs into high-resolution, pixelated geometries with accurate control of registration, efficient utilization of the materials, and minimal chemical contamination. Here, we present a highresolution, additive nanofabrication technique that explo

13、its controlled, electrohydrodynamic ejection of fluids through fine nozzles for the patterned delivery of QDs to a target substrate.29 The method is similar in terms of its additive nature, compatibility with multiple material “inks”, and programmable definition of pattern layouts (i.e., maskless op

14、eration) to conventional inkjet techniques, but it offers levels of resolution, registration, and thickness control that are vastly superior. This electrohydrodynamic jet (e-jet) printing procedure3032 also does not require prepatterned topographical or chemical patterns to guide material flows. Pre

15、vious work demonstrates compatibility with a wide variety of inks, ranging from carbon nanotubes (CNTs)33 to proteins and DNA,34,35 to block copolymers,36,37 conducting polymers and many others. The work reported here establishes versatile capabilities when used with solution suspensions of QDs, thr

16、ough demonstrations of wide-ranging, multicolored patterns of QDs in various geometries. Such printed structures can be incorporated into functional QD LEDs with expected properties. Unusual printed device configurations such as vertical stacks of QDs enable LEDs with visible light emission at tailo

17、red wavelengths胶体量子点（量子点）是半导体材料的纳米晶体，可以使用散装液相技术合成和加工。量子点的尺寸依赖的电光特性可以利用在不寻常类别的电子和光电子器件上，在固态照明，信息显示，成像探测器，和其他系统中具有潜在的使用价值。基于量子点的发光二极管（QD LED）因其宽泛的色彩可调性，高亮度，和窄的发射带宽的特点，而散发出独特的魅力。但在实现电荷传输光发射的优化控制、形成必要的多层器件结构方面，挑战仍然存在。过去几年对前一课题的研究已经有了重大进展。解决后者的方法包括：传统的喷墨印花，转移印花的先进技术，在初步的可行性论证，蘸笔纳米光刻技术。其目的是使图案红、绿、蓝（RGB）的量

18、子点层叠具有高分辨率、像素化的几何形状与登记的精确控制、材料的有效利用和最小的化学玷污的优点。在这里，我们提出了一个高分辨率，附加纳米加工技术，利用受控电流体喷射，通过极细喷嘴将图案化量子点传递到目标基底的方法。该方法与其附加性质类似，兼容多种原料的“墨水”和可编程的模式布局的定义（对比传统的喷墨技术而言。即，无掩模操作），并且它提供的分辨率水平、登记和厚度控制，都大大优于传统技术。这种电流体喷射（e-喷射）印刷过程也不需要预先定型的地形或化学模式来指导物质流。以前的工作表明，e-喷射印刷与各种各样的油墨，从碳纳米管（CNTs）到蛋白质和DNA，再到嵌段共聚物、导电聚合物和许多其他材料都能实现

19、兼容。这里的报告工作是在使用量子点溶液悬浮液，通过广泛的各种几何图案的多色量子点模式的验证的基础上完成的。它建立了e-喷射通用性的能力。这样的印刷结构可以纳入预期性能与功能的量子点发光二极管。非常印刷设备的配置，如垂直量子点堆叠，能使发光二极管发出指定波长的可见光。Figure 1. Electrohydrodynamic jet printing as a route to highresolution patterns of QDs. (a) An optical microscope image of a metal-coated glass nozzle (5 m internal d

20、iameter at the tip) and a target substrate during the printing process. (b) Schematic illustration corresponding to the image of (a). The inks consist of a dilute solutions (0.25%) of different types of QDs (CdSe/CdZnSeS green or CdSe/CdS/ZnS red core/shell QDs) in dichlorobenzene. The solvent evapo

21、rates during and immediately after printing. (c,d) QDs printed in linear geometries: (c) optical and (d) fluorescence images of a pattern generated in a continuous printing mode. (e,f) QDs printed into filled square geometries: (e) optical and (f) fluorescence images of an array of squares (30 30 m2

22、 ) formed by raster scanning in the continuous mode. The spacings between adjacent lines decreases from top left to bottom right. (g,h) QDs printed into complex shapes: (g) optical and (h) composite fluorescence images of a pattern of red and green QDs printed in a raster scanning mode to obtain a u

23、niform coverage. (i,j) QDs printed into arrays of spots: (i) optical and (j) composite fluorescence images of arrays of red and green QDs printed in a drop on demand mode. Nozzles with internal diameters of 2 and 5 m were used in the results presented above.图1.电动喷墨打印作为得到一种高分辨率模式量子点的的途径。（a）表示一个金属镀膜玻璃

24、细管的光学显微镜图像（尖端处的内径为5m）和一个目标基板。（b）示意图对应于图像（a）。这个油墨包括了在二氯代苯中不同类型量子点的稀释剂（0.25%）（CdSe / CdZnSeS绿色或CdSe / CdS / ZnS红色核/壳状量子点）。溶剂在打印之后立即蒸发。（c，d）打印的量子点呈线性几何形状：（c）光学图像和（d）荧光图像在连续打印模式下生成。（e，f）量子点打印呈填充正方形几何形状：正方形阵列（30x30um2）的（e）光学图像和（f）荧光图像通过连续光栅扫描模式形成。相邻线之间的间距从左上角到右下角减小。（g，h）打印成复杂形状的量子点：红色和绿色量子点的（g）光学图像和（h）复合

25、荧光图像是以光栅扫描模式打印以获得均匀的覆盖。（i，j）打印成斑点阵列的量子点：阵列的红色和绿色量子点的（i）光学图像和（j）复合荧光图像是按需模式下打印。内径为2和5m的喷嘴用于上述结果。Figure 1 demonstrates the ability of e-jet printing to form diverse patterns of multiple types of QDs with good registration. Here, solutions of QDs (CdSe/CdZnSeS green or CdSe/CdS/ZnS red core/shell QDs)3

26、8,39 in organic solvents (dichlorobenzene) serve as the inks (Supporting Information 1). A voltage bias applied between a substrate and a metal-coated glass capillary induces rapid flow of the ink through the fine opening (e.g., 5 m) at the end of the nozzle (Figure 1a,b and Supporting Information 2

27、). The simultaneous programmed movement of the substrate and control of the voltage enables patterned delivery of QDs in nearly any geometry. Line patterns can be efficiently created by operating the e-jet system in a mode that involves ink delivery in the form of a single, continuous jet, as shown

28、in Figure 1c,d. In a raster scanning operation with this mode, QDs can be printed as filled solid patterns (e.g., squares of 30 30 m2 ) as in Figure 1e,f. The spacings between adjacent printed lines, or the number of overlaid printing sequences can be varied to control the thicknesses of the pattern

29、s without significant change in the lateral dimensions. Increases in thickness manifest as increased fluorescence (Figure 1f). Filled polygons with complex geometries can be designed by converting an image to numerical commands for automated printing. Different QDs can be delivered with precise regi

30、stration to different regions of a single pattern. Figure 1g,h presents an example of a printed cartoon image of an apple formed with green and red QDs. The strong, spatially uniform patterns of fluorescence suggest full area coverage and uniform thickness across the pattern. In a pulsatile mode, e-

31、jet printing yields arrays of circular deposits of QDs with diameters of 3.9 m (Figure 1i,j), using drop-on-demand operation. Here, control over the number of delivered droplets determines the thickness of the printed materials.图1显示了喷墨印刷形成的量子点具有良好的登记多个类型不同模式的能力。在这里，溶于有机溶剂（氯苯）中量子点溶液（CdSe/cdznses绿或CdS

32、e/CdS/ZnS红核壳量子点）用作打印油墨（支持信息1）。加在基底和金属镀膜玻璃细管之间的偏压，使油墨通过喷嘴末端的极细开口（例如，5m）时，产生高速油墨流（图1a，b，支持信息2）。同时编程运行的基板和控制电压，使图案化的量子点几乎能够以任何几何形状传送。线模式可以通过操作e-喷射系统有效地创建，该系统涉及油墨传送模式的单一或连续油墨喷射形式，如图1c，d所示。 在这种模式光栅扫描操作下，量子点可以如图1e，f所示那样打印填充固体模式（例如，3030m2）。相邻打印线之间的间距或覆盖打印序列号可以发生改变来控制模式的横向尺寸，然厚度却无显著变化。荧光增强时，相应厚度也会明显增加（图1f）。通过将图像转换为自动打印的数字命令，可以设计出复杂的几何图形填充的多边形。不同的量子点可以通过精确的登记传送到单一模式的不同区域。图1g，h介绍了印刷的卡通形象的例子，图示中的苹果形象是由绿色和红色量子点形成的。强烈的空间均匀荧光图案能显示出全区域覆盖和跨越图案的均匀厚度。在脉冲模式中，采用按需运行的方式，e-喷墨印刷产生直径3.9m的量子点圆形存储阵列（图1i，j）。在这里，通过控制传送液滴量的多少来决定印刷材料的厚度。Patterning QDs with precise contr