Name: development of efficient oleds from solution deposition
Uploaded: 2022-11-04T12:30:00
Description: Watch this Scientific Journal Video about Development of Efficient OLEDs from Solution Deposition at JoVE.com

作者要感谢欧盟地平线2020研究和创新计划根据Marie Sklodowska-Curie资助协议编号674990的“EXCILIGHT”项目。这项工作也是在i3N，UIDB / 50025 / 2020和UIDP / 50025 / 2020项目范围内开发的，由国家基金通过FCT / MEC资助。

注意：以下步骤涉及使用不同的溶剂和有机材料，因此在处理时必须格外小心。使用通风柜和防护设备，如实验室眼镜、口罩、手套和实验室外套。材料的称重应使用高精度秤机精确完成。为了确保基材的清洁度、薄膜的溶液沉积和蒸发，建议所有程序在受控环境或手套箱中进行。在使用旋涂机、微量移液器、热蒸发器、有机材料和溶剂之前，必须查阅所有安全数据表。
1. 主?...

这里用于在简单的器件结构中制造高效OLED的协议相对简单。电迁移率不仅受器件层的材料成分的调节，而且严重取决于薄膜形态。溶液的制备以及溶剂和浓度的适当选择很重要。不会发生材料聚集，这意味着在纳米尺度上完全溶解。观察溶液的粘度也很重要。高粘度导致溶液在基材上的高接触角，反之亦然。在这两种情况下，都可以通过旋涂形成非均匀的薄膜。此外，应避免在滴下溶液之前开始...

日常生活中使用的有机电子产品的增加已成为无与伦比的现实。在几种有机电子应用中，OLED可能是最具吸引力的。其图像质量、分辨率和色彩纯度使OLED成为显示器的首选。此外，在极薄、柔韧、轻便且易于调色的OLED中实现大面积发射的可能性在照明方面也有应用。然而，与大面积发射器制造工艺相关的一些技术问题推迟了进一步的应用。
随着第一个OLED在低施加电压下工作1，已经设计了固态照明的新范式，尽管外部量子效率（EQE）较低。OLED EQE是通过发射光子（光）与注入的载流子（电流）的比率获得的。最大预期 EQE 的简单理论估计等于 η x ηint 2。 内部效率（ηint）可以用ηint=γ  x x <img alt="Equation 1" src="/files/ftp_upload/61071/61071eq01.jpg" style="margin: auto;"> ΦPL近似，其中γ对应于电荷平衡因子，ΦPL是光致发光量子产率（PLQY）， <img alt="Equation 1" src="/files/ftp_upload/61071/61071eq01.jpg" style="margin: auto;"> 是发射激子（电子空穴对）产生的效率。最后，η是 外耦合效率2。如果不考虑外耦合，则注意力集中在三个主题上：（1）材料在产生辐射复合激子方面的效率如何，（2）发射层的效率如何，以及（3）器件结构在促进良好平衡的电气系统方面的效率如何3。
纯荧光有机发射器只有25%的内部量子效率（IQE）。根据自旋规则，禁止从三重态到单重态（T→S）的辐射跃迁4。因此，75%的激发电载流子对光子5的发射没有贡献。这个问题首先在有机发射器磷光OLED6，7，8，9，10中使用过渡金属克服，据报道IQE接近100%11，12，13，14，15，16.这是由于有机化合物和重过渡金属之间的自旋轨道耦合。这种发射器的缺点是成本高，稳定性差。最近，Adachi17，18关于激发三重态和单重态（∆EST）之间低能量分离的纯有机化合物的化学合成报告产生了一个新的框架。虽然不是新的19，但在OLED中成功应用TADF工艺使得在不使用过渡金属配合物的情况下获得高效率成为可能。
在这种无金属有机发射器中，处于三重态的激发载流子很有可能填充到单重态;因此，IQE可以达到100%5，20，21，22的理论极限。这些TADF材料提供了可以辐射重组的激子。然而，这些发射器需要在矩阵主体中分散，以避免在主客体概念中淬灭3，20，21，23，24。此外，其效率取决于主机（有机基质）如何适应客体（TADF）材料25。此外，有必要将器件结构（即薄层、材料和厚度）理想化，以实现电平衡器件（空穴和电子之间的平衡以避免损耗）26。为电平衡设备实现最佳的主机-来宾系统是提高EQE的基础。在基于TADF的系统中，这并不简单，因为EML中电载流子迁移率的变化不容易调整。
使用TADF发射器，大于20%的EQE值很容易获得26，27，28，29。然而，器件结构通常由三到五个有机层（空穴传输/阻塞和电子传输/阻塞层，分别为HTL / HBL和ETL / EBL）组成。此外，它采用热蒸发工艺制造，成本高，技术复杂，几乎仅用于显示应用。根据HOMO（最高占据分子轨道）和LUM（最低未占据分子轨道）水平，载流子的电迁移率和厚度，每一层都可以注入，运输和阻断载流子，并保证发射层（EML）中的复合。
降低器件复杂性（例如，简单的两层结构）通常会导致EQE明显降低，有时降至5%以下。这是由于EML中的电子和空穴迁移率不同而发生的，并且器件变得电不平衡。因此，EML中的发射效率变得很低，而不是激子产生的高效率。此外，由于在高施加电压下激子浓度高，激发寿命长，EQE会随着亮度的大幅降低而发生明显的滚降24，30，31。克服这些问题需要强大的能力来操纵发射层的电特性。对于使用溶液沉积方法的简单OLED架构，EML的电性能可以通过溶液制备和沉积参数32来调节。
以前已使用有机基器件的溶液沉积方法31。与热蒸发工艺相比，OLED制造因其结构简化，成本低和大面积生产而备受关注。随着过渡金属配合物OLED的高度成功，主要目标是增加发射面积，但保持器件结构尽可能简单33。卷对卷（R2R）34，35，36，喷墨打印37，38，39和槽模40等方法已成功应用于OLED的多层制造，这是一种可能的工业方法。
尽管有机层的溶液沉积方法是简化器件架构的不错选择，但并非所有所需的材料都可以轻松沉积。使用两种类型的材料：小分子和聚合物。在溶液沉积方法中，小分子有一些缺点，例如薄膜均匀性差，结晶和稳定性差。因此，聚合物主要用于，因为它能够在大型柔性基材上形成具有低表面粗糙度的均匀薄膜。此外，材料在适当的溶剂（主要是氯仿、氯苯、二氯苯等有机溶剂）、水或醇衍生物中应具有良好的溶解性。
除了溶解度问题外，还必须保证一层中使用的溶剂不应充当前一层的溶剂。这允许通过湿法工艺沉积多层结构;但是，存在限制41。最典型的器件结构使用一些溶液沉积层（即发射层）和一个热蒸发层（ETL）。此外，薄膜均匀性和形态在很大程度上取决于沉积方法和参数。通过这些层的电荷传输完全受这种形态的支配。然而，应该明智地在所需的最终器件和制造过程的兼容性之间进行权衡。调整沉积参数是成功的关键，尽管这是一项耗时的工作。例如，旋涂不是一个简单的技术。虽然看起来很简单，但从纺丝基板顶部的溶液形成薄膜有几个方面需要注意。
除了薄膜厚度优化、纺丝速度和时间的操纵（厚度是两个参数的指数衰减）外，还必须调整实验者的行动以获得良好的结果。正确的参数还取决于溶液粘度、沉积面积和溶液在基材上的润湿性/接触角。没有唯一的参数集。只有对溶液/底物进行特定调整的基本假设才能产生预期的结果。此外，可以按照此处描述的方案优化依赖于层分子构象和形态的电性能以获得所需的结果。一旦完成，该过程就简单可行。
然而，降低器件结构复杂性会导致最大EQE降低;虽然，在效率与亮度方面可以实现折衷。由于这种折衷方案允许实际应用，简单、大面积兼容和低成本工艺的盈余可以成为现实。本文介绍这些要求以及如何开发方法来处理所需问题。
该协议侧重于绿色TADF发射器2PXZ-OXD [2，5-双（4-（10H-吩噁嗪-10-基）苯基）-1，3，4-恶二唑]42 作为由PVK [聚（N-乙烯基咔唑）]和OXD-7 [1，3-双[2-（4-叔丁基苯基）-1，3，4-恶二氮-5-基]苯组成的宿主基质中的客体，对应于EML。使用TmPyPb[1，3，5-三（间吡啶-3-基苯基）苯]的电子传输层（ETL）。阳极和阴极的功函数都得到了优化。阳极由ITO（氧化铟锡）和高导电聚合物PEDOT：PSS[聚（3，4-乙烯二氧噻吩）-聚（苯乙烯磺酸酯）]组成，阴极由双层铝和LiF（氟化锂）组成。
最后，PEDOT：PSS和EML（PVK：OXD-7：2PXZ-OXD）都通过旋涂沉积，而TmPyPb，LiF和Al则热蒸发。考虑到PEDOT：PSS的导电金属性质，该器件是典型的“两个有机层”，结构尽可能简单。在EML中，TADF客体（10%重量）分散在由PVK0.6+OXD-70.4组成的宿主（90%重量）中。

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development of efficient oleds from solution deposition

基于热激活延迟荧光（TADF）概念的高效有机发射器的使用很有趣，因为它们具有100%的内部量子效率。这里介绍一种基于TADF发射器的溶液沉积方法，该方法基于简单器件结构中的TADF发射器制造高效有机发光二极管（OLED）。这种快速、低成本和高效的工艺可用于遵循主机-来宾概念的所有OLED发光层。描述了基本步骤以及进一步繁殖的必要信息。目标是建立一个通用协议，可以很容易地适应目前正在研究和开发的主要有机排放者。

图5 显示了该器件的主要结果。导通电压极低（~3 V），这对于两层有机层器件来说是一个有趣的结果。最大亮度约为 8，000 cd/m2 ，不使用积分球。ηc、ηp和EQE的最大值分别约为16 cd/A、10 lm/W和8%。虽然结果不是该TADF发射器的最佳品质因数，但它们是使用该发射器通过求解工艺方法在如此简单的器件结构中找到的最佳品质因数。
据...

Watch this Scientific Journal Video about Development of Efficient OLEDs from Solution Deposition at JoVE.com

Development of Efficient OLEDs from Solution Deposition

这里介绍的是一种协议，用于制造高效、简单、溶液沉积的具有低滚降的有机发光二极管。

基于溶液沉积的高效OLED开发

The use of highly efficient organic emitters based on the thermally activated delayed fluorescence (TADF) concept is interesting due to their 100% ...

以有效的方式专注于印刷电子领域的新重要领域，特别是针对操作系统，为真正针对螺栓机概念优化的工艺开辟了可能性。操作系统润滑的简单性在简单的设备架构和有用的效率之间取得了很好的权衡，这是一个巨大的技术问题。主要问题除了正确选择主机掌握指标、成分、浓度、溶剂等外，还可以集中分为三个方面，自旋编码位置、溶剂制备和电荷的电平衡。通过溶液持久工艺进行润滑似乎很简单，因为它的器件纤维含量很高。制造过程中的一些关键方面需要 35。首先准备主机矩阵。将15毫克OXD7加入小瓶中。然后加入五毫克PVK。然后将10毫克2PXZOXDTADF发射器加入另一个小瓶中。向装有宿主基质的小瓶中加入两毫升氯苯，在装有TADF材料的小瓶中加入一毫升氯苯。两个小瓶中氯苯的最终浓度应为每毫升10毫克。用清洁的小磁力搅拌棒搅拌溶液至少三个小时，直到材料完全溶解。确保小瓶被相应的盖子安全地覆盖，并用有机化学安全膜密封，以避免溶剂蒸发。在含有1%hellmanex溶液的超声波浴中依次清洁预先图案化的印度氧化锡或ITO基材，在95摄氏度的水中，然后在室温下丙酮，然后在室温下至丙醇，每次浴15分钟。用镊子处理基材，只在角落接触它们。尝试用氮气助焊剂去除基材，以去除任何清洁溶剂残留物。然后将基材暴露在紫外线臭氧处理下五分钟，ITO膜朝上。用0.45微米聚偏二氟乙烯过滤器过滤PEDOT：PSS，并在微量移液器中填充100微升溶液。小心地将基材放在旋转打码车上并激活真空系统以固定它。将ITO面朝上旋转，并尽可能使基板区域居中。将旋涂的参数设置为 3， 000 RPM，持续 30 秒。在低旋转时设置两到三秒的初始步长。保持微量移液器垂直于基板，将PEDOT：PSS放在基板中间并启动旋转编码器。自旋编码完成后，关闭真空并用镊子取出基板。使用浸泡在水中的小棉签去除阴极和基板角落区域周围的多余沉积薄膜，保持中心像素区域不变。将基质在烤箱或120摄氏度的热板上孵育15分钟以除去PEDOT：PSS溶剂，然后将其转移到手套箱中并在室温下冷却。为了制备沉浸式层的溶液，将1.8毫升的宿主溶液和0.2毫升的TADF溶液混合在一个干净的小瓶中。用0.1微米PTFE过滤器过滤溶液，然后在室温下搅拌15分钟。按照前面描述的程序将第二种溶液与自旋编码器以 2， 000 RPM 旋转 60 秒。使用浸泡在氯苯中的棉签去除第二层薄膜的任何多余部分。将基材放在手套箱内的热板上，在70摄氏度下放置30分钟，以完全去除多余的氯苯。然后让它在室温下冷却。使用所需的蒸发掩模将基板插入样品架，确保薄膜朝下。包括必要的坩埚，并用适当的材料填充它们。将装有样品的底物支架放入蒸发器样品架中。关闭腔室并将其向下泵送，确保遵循制造商对特定蒸发器系统的说明。蒸发40纳米的TNPYPB薄膜，然后蒸发两纳米的氟化锂薄膜，最后蒸发100纳米的铝膜。此处显示了制造 LED 的特性。导通电压极低，约为 3 伏，对于双有机层器件来说，这是一个有趣的结果。最大亮度约为每平方米8， 000坎德拉，不使用积分球。电流效率、功率效率和外部量子效率的最大值分别约为每安培16坎德拉、每瓦10流明和8%。设备结构简单性和可靠性之间的良好权衡 应断言 最好的信息 在所有方面没有缺陷 特别重要的是，金属概念可以扩展到不同类型的参数，例如有机和无机材料。虽然我们特别特殊，但主要思想是

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Engineering

Fabrication of Nano-engineered Transparent Conducting Oxides by Pulsed Laser Deposition

Nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas allows the deposition of metal oxides with tunable morphology, structure, density and stoichiometry by a proper control of the plasma plume expansion dynamics. Such versatility can be exploited to produce nanostructured films from compact and dense to nanoporous characterized by a hierarchical assembly of nano-sized clusters. In particular we describe the detailed methodology to fabricate two types of Al-doped ZnO (AZO) films as transparent electrodes in photovoltaic devices: 1) at low O2 pressure, compact films with electrical conductivity and optical transparency close to the state of the art transparent conducting oxides (TCO) can be deposited at room temperature, to be compatible with thermally sensitive materials such as polymers used in organic photovoltaics (OPVs); 2) highly light scattering hierarchical structures resembling a forest of nano-trees are produced at higher pressures. Such structures show high Haze factor (&gt;80%) and may be exploited to enhance the light trapping capability. The method here described for AZO films can be applied to other metal oxides relevant for technological applications such as TiO2, Al2O3, WO3 and Ag4O4.

We describe the experimental method to deposit nanostructured oxide thin films by nanosecond Pulsed Laser Deposition (PLD) in the presence of a background gas. By using this method Al-doped ZnO (AZO) films, from compact to hierarchically structured as nano-tree forests, can be deposited.

制备纳米设计的脉冲激光沉积透明导电氧化物

Nanosecond Pulsed  Laser Deposition (PLD) in the presence of a background gas allows the deposition  of metal oxides with tunable morphology, structure, ...

科研

工程学

Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, and defects within the cement matrix. Failures and defects within the cement will ultimately lead to fluid migration, resulting in inter-zonal fluid migration and premature well abandonment. Currently, there are over 1.8 million operating wells worldwide and over one third of these wells have leak related problems defined as Sustained Casing Pressure (SCP)1. 
The focus of this research was to develop an experimental setup at bench-scale to explore the effect of mechanical manipulation of wellbore casing-cement composite samples as a potential technology for the remediation of gas leaks. 
The experimental methodology utilized in this study enabled formation of an impermeable seal at the pipe/cement interface in a simulated wellbore system. Successful nitrogen gas flow-through measurements demonstrated that an existing microannulus was sealed at laboratory experimental conditions and fluid flow prevented by mechanical manipulation of the metal/cement composite sample. Furthermore, this methodology can be applied not only for the remediation of leaky wellbores, but also in plugging and abandonment procedures as well as wellbore completions technology, and potentially preventing negative impacts of wellbores on subsurface and surface environments.

This article reports on a laboratory scale investigation of an existing field procedure and its adaptation for sealing of leaky wellbores. It consists of mechanical expansion of metal pipe, which results in an improved metal/cement bond, ultimate sealing of hydraulic pathways and prevention of gas leaks caused by the presence of a microannular channel.

钢管机械性扩张为解决井眼漏

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe ...

Making Record-efficiency SnS Solar Cells by Thermal Evaporation and Atomic Layer Deposition

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent thermal evaporation, and it absorbs visible light strongly. However, for a long time the record power conversion efficiency of SnS solar cells remained below 2%. Recently we demonstrated new certified record efficiencies of 4.36% using SnS deposited by atomic layer deposition, and 3.88% using thermal evaporation. Here the fabrication procedure for these record solar cells is described, and the statistical distribution of the fabrication process is reported. The standard deviation of efficiency measured on a single substrate is typically over 0.5%. All steps including substrate selection and cleaning, Mo sputtering for the rear contact (cathode), SnS deposition, annealing, surface passivation, Zn(O,S) buffer layer selection and deposition, transparent conductor (anode) deposition, and metallization are described. On each substrate we fabricate 11 individual devices, each with active area 0.25 cm2. Further, a system for high throughput measurements of current-voltage curves under simulated solar light, and external quantum efficiency measurement with variable light bias is described. With this system we are able to measure full data sets on all 11 devices in an automated manner and in minimal time. These results illustrate the value of studying large sample sets, rather than focusing narrowly on the highest performing devices. Large data sets help us to distinguish and remedy individual loss mechanisms affecting our devices.

Tin sulfide (SnS) is a candidate material for Earth-abundant, non-toxic solar cells. Here, we demonstrate the fabrication procedure of the SnS solar cells employing atomic layer deposition, which yields 4.36% certified power conversion efficiency, and thermal evaporation which yields 3.88%.

通过热蒸发和原子层沉积使记录效率的SnS太阳能电池

Tin sulfide (SnS) is a candidate absorber material for Earth-abundant, non-toxic solar cells. SnS offers easy phase control and rapid growth by congruent ...

Formation of Thick Dense Yttrium Iron Garnet Films Using Aerosol Deposition

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% of the bulk. The primary advantage of AD is that the deposition takes place entirely at ambient temperature; thereby enabling film growth in material systems with disparate melting temperatures. This report describes in detail the processing steps for preparing the powder and for performing AD using the custom-built system. Representative characterization results are presented from scanning electron microscopy, profilometry, and ferromagnetic resonance for films grown in this system. As a representative overview of the capabilities of the system, focus is given to a sample produced following the described protocol and system setup. Results indicate that this system can successfully deposit 11 &#181;m thick yttrium iron garnet films that are &#160;&#62; 90% of the bulk density during a single 5 min deposition run. A discussion of methods to afford better control of the aerosol and particle selection for improved thickness and roughness variations in the film is provided.

This report describes the use of a custom-built system to perform aerosol deposition of thick films of yttrium iron garnet onto sapphire substrates at RT. The deposited films are characterized using scanning electron microscopy, profilometry, and ferromagnetic resonance to give a representative overview of the capabilities of the technique.

浓稠钇铁石榴石薄膜的形成使用气溶胶沉积

Aerosol deposition (AD) is a thick-film deposition process that can produce layers up to several hundred micrometers thick with densities greater than 95% ...

Research and Development of High-performance Explosives

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. For newly developed formulations, the process begins with small-scale mixes, thermal testing, and impact and friction sensitivity. Only then do subsequent larger scale formulations proceed to detonation testing, which will be covered in this paper. Recent advances in characterization techniques have led to unparalleled precision in the characterization of early-time evolution of detonations. The new technique of Photonic Doppler Velocimetry (PDV) for the measurement of detonation pressure will be shared and compared with traditional fiber-optic detonation velocity and plate-dent calculation of detonation pressure. In particular, the role of aluminum in explosive formulations will be discussed. Recent developments led to the development of explosive formulations that result in reaction of aluminum very early in the detonation product expansion. This enhanced reaction leads to changes in the detonation velocity and pressure due to reaction of the aluminum with oxygen in the expanding gas products.

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance tests to verify theoretical calculations. This paper will share typical development tests associated with the measurement of detonation velocity and detonation pressure.

高性能炸药的研究与发展

Developmental testing of high explosives for military applications involves small-scale formulation, safety testing, and finally detonation performance ...

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl4) to neutral gold Au(0) by reducing agents, such as sodium citrate or sodium borohydride. The extension of this method to decorate iron oxide or similar nanoparticles with gold nanoparticles to create multifunctional hybrid Fe2O3-Au nanoparticles is straightforward. This approach yields fairly good control over Au nanoparticle dimensions and loading onto Fe2O3. Additionally, the Au metal size, shape, and loading can easily be tuned by changing experimental parameters (e.g., reactant concentrations, reducing agents, surfactants, etc.). An advantage of this procedure is that the reaction can be done in air or water, and, in principle, is amenable to scaling up. The use of such optically tunable Fe2O3-Au nanoparticles for hyperthermia studies is an attractive option as it capitalizes on plasmonic heating of gold nanoparticles tuned to absorb light strongly in the VIS-NIR region. In addition to its plasmonic effects, nanoscale Au provides a unique surface for interesting chemistries and catalysis. The Fe2O3 material provides additional functionality due to its magnetic property. For example, an external magnetic field could be used to collect and recycle the hybrid Fe2O3-Au nanoparticles after a catalytic experiment, or alternatively, the magnetic Fe2O3 can be used for hyperthermia studies through magnetic heat induction. The photothermal experiment described in this report measures bulk temperature change and nanoparticle solution mass loss as functions of time using infrared thermocouples and a balance, respectively. The ease of sample preparation and the use of readily available equipment are distinct advantages of this technique. A caveat is that these photothermal measurements assess the bulk solution temperature and not the surface of the nanoparticle where the heat is transduced and the temperature is likely to be higher.

Multifunctional Hybrid Fe2O3-Au Nanoparticles for Efficient Plasmonic Heating

We describe the synthesis and properties of multifunctional Fe2O3-Au nanoparticles produced by a wet chemical approach and investigate their photothermal properties using laser irradiation. The composite Fe2O3-Au nanoparticles retain the properties of both materials, creating a multifunctional structure with excellent magnetic and plasmonic properties.

多功能混合铁<sub&gt; 2</sub&gt; 0<sub&gt; 3</sub&gt; -Au纳米粒子高效的电浆暖气

One of the most widely used methods for manufacturing colloidal gold nanospherical particles involves the reduction of chloroauric acid (HAuCl4) to ...

Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal inks. For the photoactive absorber layer, colloidal CdTe and CdSe nanocrystals (3-5 nm) are synthesized using an inert hot injection technique and cleaned with precipitations to remove excess starting reagents. Similarly, gold nanocrystals (3-5 nm) are synthesized under ambient conditions and dissolved in organic solvents. In addition, precursor solutions for transparent conductive indium tin oxide (ITO) films are prepared from solutions of indium and tin salts paired with a reactive oxidizer. Layer-by-layer, these solutions are deposited onto a glass substrate following annealing (200-400 &#176;C) to build the nanocrystal solar cell (glass/ITO/CdSe/CdTe/Au). Pre-annealing ligand exchange is required for CdSe and CdTe nanocrystals where films are dipped in NH4Cl:methanol to replace long-chain native ligands with small inorganic Cl- anions. NH4Cl(s) was found to act as a catalyst for the sintering reaction (as a non-toxic alternative to the conventional CdCl2(s) treatment) leading to grain growth (136&#177;39 nm) during heating. The thickness and roughness of the prepared films are characterized with SEM and optical profilometry. FTIR is used to determine the degree of ligand exchange prior to sintering, and XRD is used to verify the crystallinity and phase of each material. UV/Vis spectra show high visible light transmission through the ITO layer and a red shift in the absorbance of the cadmium chalcogenide nanocrystals after thermal annealing. Current-voltage curves of completed devices are measured under simulated one sun illumination. Small differences in deposition techniques and reagents employed during ligand exchange have been shown to have a profound influence on the device properties. Here, we examine the effects of chemical (sintering and ligand exchange agents) and physical treatments (solution concentration, spray-pressure, annealing time and annealing temperature) on photovoltaic device performance.

This protocol describes the synthesis and solution deposition of inorganic nanocrystals layer by layer to produce thin film electronics on non-conductive surfaces. Solvent-stabilized inks can produce complete photovoltaic devices on glass substrates via spin and spray coating following post-deposition ligand exchange and sintering.

全面解决方案处理的无机纳米晶体光伏器件的制造

We demonstrate a method for the preparation of fully solution processed inorganic solar cells from a spin and spray coating deposition of nanocrystal ...

Electrospray Deposition of Uniform Thickness Ge23Sb7S70 and As40S60 Chalcogenide Glass Films

Solution-based electrospray film deposition, which is compatible with continuous, roll-to-roll processing, is applied to chalcogenide glasses. Two chalcogenide compositions are demonstrated: Ge23Sb7S70 and As40S60, which have both been studied extensively for planar mid-infrared (mid-IR) microphotonic devices. In this approach, uniform thickness films are fabricated through the use of computer numerical controlled (CNC) motion. Chalcogenide glass (ChG) is written over the substrate by a single nozzle along a serpentine path. Films were subjected to a series of heat treatments between 100 &#176;C and 200 &#176;C under vacuum to drive off residual solvent and densify the films. Based on transmission Fourier transform infrared (FTIR) spectroscopy and surface roughness measurements, both compositions were found to be suitable for the fabrication of planar devices operating in the mid-IR region. Residual solvent removal was found to be much quicker for the As40S60 film as compared to Ge23Sb7S70. Based on the advantages of electrospray, direct printing of a gradient refractive index (GRIN) mid-IR transparent coating is envisioned, given the difference in refractive index of the two compositions in this study.

Electrospray Deposition of Uniform Thickness Ge23Sb7S70 and As40S60 Chalcogenide Glass Films

A method of uniform thickness solution-derived chalcogenide glass film deposition is demonstrated using computer numerical controlled motion of a single-nozzle electrospray.

厚度均匀葛电沉积<sub&gt; 23</sub&gt;锑<sub&gt; 7</sub&gt;取值<sub&gt; 70</sub&gt;和As<sub&gt; 40</sub&gt;取值<sub&gt; 60</sub&gt;硫系玻璃薄膜

Solution-based electrospray film deposition, which is compatible with continuous, roll-to-roll processing, is applied to chalcogenide glasses. Two ...

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical properties. The possibility of doping was investigated by adding monovalent cation halides with similar ionic radii to Pb2+, including Cu+, Na+, and Ag+. A shift in the Fermi level and a remarkable decrease of sub-bandgap optical absorption, along with a lower energetic disorder in the perovskite, was achieved. An order-of-magnitude enhancement in the bulk hole mobility and a significant reduction of transport activation energy within an additive-based perovskite device was attained. The confluence of the aforementioned improved properties in the presence of these cations led to an enhancement in the photovoltaic parameters of the perovskite solar cell. An increase of 70 mV in open circuit voltage for AgI and a 2 mA/cm2 improvement in photocurrent density for NaI- and CuBr-based solar cells were achieved compared to the pristine device. Our work paves the way for further improvements in the optoelectronic quality of CH3NH3PbI3 perovskite and subsequent devices. It highlights a new avenue for investigations on the role of dopant impurities in crystallization and controls the electronic defect density in perovskite structures.

Monovalent Cation Doping of CH3NH3PbI3 for Efficient Perovskite Solar Cells

Here, we present a protocol to adjust the properties of solution-processed CH3NH3PbI3 through the incorporation of monovalent cation additives in order to achieve highly efficient perovskite solar cells.

CH的单价阳离子兴奋剂<sub&gt; 3</sub&gt; NH<sub&gt; 3</sub&gt;碘化铅<sub&gt; 3</sub&gt;对钙钛矿型高效太阳能电池

Here, we demonstrate the incorporation of monovalent cation additives into CH3NH3PbI3 perovskite in order to adjust the optical, excitonic, and electrical ...

Fabrication of Ultra-thin Color Films with Highly Absorbing Media Using Oblique Angle Deposition

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present an advanced method for fabricating ultra-thin color films with improved characteristics. The proposed process addresses several fabrication issues, including large area processing. Specifically, the protocol describes a process for fabricating ultra-thin color films using an electron beam evaporator for oblique angle deposition of germanium (Ge) and gold (Au) on silicon (Si) substrates.&#160; Film porosity produced by the oblique angle deposition induces color changes in the ultra-thin film. The degree of color change depends on factors such as deposition angle and film thickness. Fabricated samples of the ultra-thin color films showed improved color tunability and color purity. In addition, the measured reflectance of the fabricated samples was converted into chromatic values and analyzed in terms of color. Our ultra-thin film fabricating method is expected to be used for various ultra-thin film applications such as flexible color electrodes, thin film solar cells, and optical filters. Also, the process developed here for analyzing the color of the fabricated samples is broadly useful for studying various color structures.

We present a detailed method for fabricating ultra-thin color films with improved characteristics for optical coatings. The oblique angle deposition technique using an electron beam evaporator allows improved color tunability and purity. Fabricated films of Ge and Au on Si substrates were analyzed by reflectance measurements and color information conversion.

用斜角沉积法制备高吸收介质的超薄彩色薄膜

Ultra-thin film structures have been studied extensively for use as optical coatings, but performance and fabrication challenges remain.&#160; We present ...