Name: effect of bending on the electrical characteristics of flexible organic single crystal-based field-effect transistors
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This work was supported by the Ministry of Science and Technology, Taiwan, Republic of China through Grant No. 101-2113-M-001-006-MY3.

1. TCDAP 12制备<ol><li>通过以下文献方法13合成TCDAP。 </li><li>由温度梯度升华法纯化TCDAP产物，用设定在340，270中的三个温度区，和250℃，分别10 -6乇12,14的真空压力下。 </li></ol> 2.成长TCDAP使用物理气相传输（PVT）系统14的单晶<ol><li>把TCDAP样品在船（5厘米长）的一端和船形加载到玻璃内管（长度为15厘米直径为1.2厘米）。 </li><li>加载内管成一个较长的玻璃管（83厘米长和2厘米，直径），并在将其推到从开口约17厘米</li><li>加载长玻璃管成铜管（60厘米长，直径为2.5厘米）的水平固定在机架上;请确保TCDAP的船位于供热面积由加热带AR定义的中间ound铜管。 </li><li>吹扫用氦气的PVT系统以30毫升/分的流速，然后打开变压器到加热带加热到310℃;保持在此温度下两天。 </li><li>该系统冷却至室温后，收集从内管的晶体。 </li></ol> 3.设备制造<ol><li>放一个200-μm厚的，透明的，预切PET制基板（2毫升×1厘米）到小瓶并通过超声处理在洗涤剂溶液，去离子水和丙酮清洗，在顺序，对于每个30分钟。干燥用氮气流在衬底。 </li><li>放置在PET基材上的双面胶带。 </li><li>检查在立体显微镜下的晶体。选择品质好，闪亮晶体，约5毫米×至0.03MM器件制造的维度。放置与双面胶带在PET基材的长度的针状TCDAP晶体平行并安全地固定。 </li><li>在立体显微镜，笏申请通过在一个线（几个毫米）微升注射器针头呃基于胶体石墨是从作为源极和漏极晶体的两端延伸。等待大约30分钟的胶体石墨干燥并测量在光学显微镜下在两个石墨点之间的距离，以确定准确的信道长度（其保持在0.6-1毫米）。 </li><li>使用碳导电胶带固定在显微镜载玻片PET基材。附近放置淀积室的热解管的端部滑动。 </li><li>称量0.5g上述介电绝缘体的前体，[2.2]对环芳烷，将其在热解管的入口附近。 </li><li>系统抽真空到10 -2乇的真空。靠近管向上的中心的热解区的预加热至700℃预先设定的温度，并在此温度下保持。 </li><li>升温[2.2]二聚二甲苯样品150℃。前体的蒸气将通过热解区得到的单体，这将凝结邻近所述热解管聚合的末端。 </li><li>让热解/聚合反应继续进行2小时。 </li><li>冷却系统，并从裂解管取出样品。 </li><li>通过测量该层的台阶高度并使用轮廓根据制造商的说明衬底决定所沉积的介电层的厚度。 </li><li>通过微升注射器针头在上介电层的晶体上方的返回线应用基于异丙醇的胶体石墨，作为栅极电极。 </li></ol> 4.测量设备的性能<ol><li>使用手术刀通过源电极/漏电极区上方的聚合物电介体膜，以便露出所述电极下方，用于连接到切割的孔。 </li><li>随着立场和夹具的帮助下，把从参数分析仪电极探头接触到源极/漏极/栅极。根据制造商的说明在不同的栅极电位记录IV特性。 注意:在此，栅电位是从-60V。设为60伏，在15V的步骤。 </li></ol> 5.弯曲疲劳试验<ol><li>为了测量拉伸状态的属性，回绕不同半径（14.0mmol毫米，12.4毫米，8.0毫米，和5.8 MM）的气缸柔性的PET衬底的背面并固定的四个侧面真空胶带PET基板到气缸。 </li><li>探针连接到源极/漏极/栅极和如4.2中所述测量在不同的栅电势的IV特性。 </li><li>为了测量在压缩状态下，包裹半左右的汽缸的端部的PET制基板的前侧的，这样，晶体/源极/漏极/栅极电极所面对的汽缸，但仍露出。固定在真空带（ 见图气缸PET基板5 </strong&gt;的）。 </li><li>探针连接到源极/漏极/栅极和如4.2中所述测量在不同的栅电势的IV特性。 注:该器件结构的横截面图在图中示出。 1。 </li></ol>

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The authors have nothing to disclose.

在本实验中，许多参数影响的场效应迁移率的成功测量。首先，在单晶应该足够大，要制造成用于特性测量的场效应装置。物理气相转移（PVT）的方法是一个允许更大的晶体生长。通过调节温度和载气的流量，尺寸的晶体最多能够获得半厘米。其次，单晶的选择是重要的。一个明显的单晶可以包含晶体包和弯曲可能导致束拆解。因此，更薄的晶体是优选的。第三，增加了一倍双面胶带必须保持在与基板表面恒定接触的晶体，作为广泛的实验表明，如果没有这样的磁带，晶体和介电层和/或电极之间的接触可能会在多个移位弯曲操作，所以使接触电阻增加了次获得不稳定或不可再现电流测量。另一个问题是在实现压缩状态下，当晶体的端部向上弯曲。当缠绕适当直径的气缸柔性衬底，晶体/源极/漏极/栅极必须通过探针访问。这是通过缠绕圆筒的端部的柔性的PET衬底的边缘进行，从而使源极/漏极/栅极区域被暴露并访问探针，同时保持弯曲基板。 在数据分析而言，这是公认的，柔性基板的弯曲可能会导致在所述电介质层的厚度，并在电容的变化。虽然这可能改变没有在流动性的计算中考虑的，应该注意这种变化应该是独立弯曲的方向。但是，在流动性的变化趋势相反应消除流动性变化的可能性是由于到t他电容变化。单晶的质量将对测量流动性大的影响。对于图8所示的数据，观察到了两个晶体中迁移率的巨大差异，这可能是由于所选择的结晶的质量。然而，当弯曲的流动性变化，这是在此工作主要关注的，的趋势形成用于从实验得出的结论的基础。 对比现有技术11，其中晶体是第一弯曲，然后置于用于测量的平坦的基板上，我们的方法允许在拉伸状态的电流测量以及压缩状态。在以前的技术中，只在电流通过的最短路径，即，压缩状态，可以测量。这种方法可使各种电性质的直接在柔性基板上进行测量。

软的电子设备，诸如传感器，显示器和耐磨电子，目前正在设计和研究更积极地，许多甚至已在市场近年来1,2,3,4发射。有机半导体材料发挥这些电子设备的一个重要的作用，由于其固有的优点，包括低开发成本，以便在溶液中或在低温下制备的能力，并且，特别是它们的灵活性时相比无机半导体5,6。对于这些电子的一个特别的考虑是，它们将受到频繁的弯曲。弯曲介绍的部件和在装置内的材料应变。因为这样的设备弯曲需要一个稳定和一致的性能。晶体管是大多数电子产品的重要组成部分，其下的弯曲性能感兴趣。许多研究已通过弯曲的有机牛逼解决了这一性能问题欣薄膜晶体管7,8。而在弯曲的电导的变化可以归因于在多晶薄膜中的变化中，晶粒之间的间距，更根本的问题是是否电导可以在弯曲的单晶内变化。它被广泛接受该有机分子之间的电荷传输强烈地依赖于分子和所涉及的中性和带电状态9之间的相互转换的重组能之间的电子耦合。电子耦合是邻近的分子之间和前沿分子轨道的重叠的距离高度敏感。良好有序晶体的弯曲引入应变，并且可以改变分子的晶体内的相对位置。这可以用一个单一的基于晶体的场效应晶体管进行测试。一报告中所使用的柔性基板上的红荧烯单晶在弯曲10，研究晶体厚度的效果。德与平的基底上制备的铜酞菁纳米线晶体虎钳被示出在弯曲11具有更高的迁移率。然而，对于一个FET器件弯曲不同方向的性质没有被探讨。 分子5,7,12,16四氯6,13- diazapentacene（TCDAP）是n型半导体材料12。 TCDAP的晶体具有在3.911埃的细胞长度沿着单元电池的一个轴相邻分子之间偏移的π-π堆叠单斜填料序。水晶沿着这个方向包装增长给长针。沿此方向测得的最大的n型场效应迁移达33.9 平方厘米/ V·秒。不像是脆而易碎许多有机晶体，TCDAP晶体被发现是高度灵活的。在这项工作中，我们使用TCDAP作为导电通道和制备在柔性底物邻单晶场效应晶体管˚F聚对苯二甲酸乙酯（PET）。迁移率测量为一个平的基底上的晶体，与设备弯曲朝向所述柔性基板（向下）或者朝着栅极/介电侧（向上）弯曲。依据相邻之间在堆叠/耦合距离的变化分析了IV数据分子。

<table><tbody><tr><td>Colloidal Graphite (water-based)</td><td>TED PELLA,INC</td><td>NO.16053</td><td></td></tr><tr><td>Colloidal Graphite (IPA-based)</td><td>TED PELLA,INC</td><td>NO.16051</td><td></td></tr><tr><td>[2.2]Paracyclophane, 99%</td><td>Alfa Aesar</td><td>1633-22-3</td><td></td></tr><tr><td>polyethylene terephthalate</td><td>Uni-Onward</td><td></td><td></td></tr><tr><td>Mini-Mite 1,100 &amp;deg;C Tube Furnaces (Single Zone)</td><td>Thermo Scientific</td><td>TF55030A</td><td></td></tr><tr><td>Agilent 4156C Precision Semiconductor Parameter</td><td>Keysight</td><td>HP4156</td><td></td></tr></tbody></table>

effect of bending on the electrical characteristics of flexible organic single crystal-based field-effect transistors

在有机半导体的电荷输送高度取决于晶体，这极大地影响了电子耦合在分子包装。然而，在软电子，其中有机半导体发挥关键作用，该装置将被弯曲或反复折叠。在晶体堆积，从而电荷输送弯曲的效果是该装置的性能是至关重要的。在这个手稿，我们描述了协议弯曲的场效应晶体管构造5,7,12,16四氯6,13-​​ diazapentacene（TCDAP）的单晶并在弯曲的晶体，以获得可再现的IV特性。结果表明，弯曲在挠性基板导致在电荷迁移率几乎可逆但相反的趋势制备的场效应晶体管，取决于弯曲方向。当该装置被朝向顶部栅极/介电层（向上，压缩状态）弯曲，并是当降低移动性的增加NT朝晶体/基板侧（向下，拉伸状态）。弯曲曲率的影响还观察，从更高的弯曲曲率所得更大的流动性的变化。有人建议，在弯曲时，从而影响电子耦合和随后的载流子传输能力的分子间π-π距离变化。

单晶X射线衍射分析表明，TCDAP是一个扩展的π系统，分子沿一个轴的图填料。图2表示通过粉末XRD对TCDAP晶体的扫描模式。一系列尖锐的峰被观测到，对应只对家族的（0，K，ℓ）面，由与晶体的粉末衍射图案进行比较。这意味着， 如图晶体结构取向。 3。 弯曲前，扁平n型TCDAP单晶晶体管，得到良好分辨饱和电流仅用于当栅极电压从-60伏在15 V以下步骤改变以60伏的正栅电压（V GS）。这表明n型行为（ 图4a）的图。图4b示出两个日志（蓝线）和漏极电流的线性（黑线）曲线作为函数的源-漏bIAS（V DS）在30 V的栅极偏置电子迁移率是从IV特性的线性状态，根据以下方程来计算， <img alt="公式1" src="/files/ftp_upload/54651/54651equation1.jpg" />或者在饱和状态根据等式， <img alt="方程2" src="/files/ftp_upload/54651/54651equation2.jpg" />其中W是沟道宽度，L为沟道长度，m是载流子迁移，C i为每介电绝缘体的每单位面积的电容，而V TH是阈值电压，分别为。 1.42厘米2 / V的平均迁移率·秒和分别实现的10 3 -10 4的开/关比。 用于弯曲试验，端部的弯曲向下应当诱导使得该被定义为"拉伸"状态的信道/电介质界面附近的导电沟道的拉伸（参照图5a），而端部的向上弯曲会诱发导电通道的压缩并因此定义为"压缩"状态（参照图5B）。在其扁平状态下的装置的IV特性相反的弯曲操作的弯曲状态后进行了检查，具有半径R = 14.0Hz毫米;截止电流几乎没有变化（参照图6）。这提供以指示该设备结构可恢复并且该设备没有在不同的方向弯曲破坏。接着，将四获得在该拉伸状态下的弯曲状态进行测定。如示于图7A &lt;/ STRONG&gt;，目前有弯曲，更使更多的弯曲（半径较小）下降。计算出的移动性被绘制为弯曲的半径的函数。如示于图8A，有流动性的下降与弯曲增加一个明显的趋势。因此，在r = 14.0Hz毫米的向下的弯曲由6.25％所造成的降低的迁移率的。流动性降低了12.5％，25％，和在12.4毫米，8.0毫米，和5.8 mm弯曲半径为37.5％，分别进行观察。在在R =14.0毫米相反，如果将该装置向上弯曲（压缩状态），在直线IV曲线的轻微移位，观察，具有增加的转变，因为弯曲增加（ 图7b）。根据该曲线的分别14.0毫米12.4毫米，8.0毫米，和5.8毫米，弯曲半径增加了5.5％，12.8％，15.2％，和19.8％的斜率计算出的迁移率（ 图8b）。 在弯晶，从不同侧面体验不同的S列车。在凹面侧，分子被压缩，并在凸面侧，分子分开，要取决于曲率的程度。因此，晶体结果的压缩和分子，分别扩散向上和向下弯曲，在栅极电介质的界面，从而增加和减少电子耦合，分别。 在一个晶体管中的电荷载体被称为是在电介质表面的几个单层内，和迁移率主要受立即层的电介质层旁边。在目前的情况下，在压缩状态下的增加的流动性和降低的流动性在拉伸状态应该最有可能是由于在晶体内的分子间的间距的变化。我们的研究结果进一步证明了电子耦合的作为分子间距离的函数的重要性。在多晶晶粒，其中所述的薄膜器件晶体可能不如我们在这些实验中使用的那样大，晶粒间的距离也可以通过弯曲，从而产生相似的结果的影响。 <img alt="图1" src="/files/ftp_upload/54651/54651fig1.jpg" /> 图1. 在柔性基板上制备的顶接触单晶的场效应晶体管的剖面图。从胶体石墨制备的源极/漏极/栅极电极，而介电绝缘体是从[2.2]的热解制备的二聚二甲苯前兆。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图2" src="/files/ftp_upload/54651/54651fig2.jpg" /> 图2. 粉末的TCDAP SI的X射线衍射图案奠定了PET基材上ngle结晶。该峰索引到家庭（0，K，ℓ）面。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图3" src="/files/ftp_upload/54651/54651fig3.jpg" /> 图3。 电荷传输通道的示意图。沿a轴的电荷传输，与（0,1,1）面（红色面）平行于基板（蓝色平面）。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54651/54651fig4.jpg" /> 图4. I DS -V DS特性。 </st荣&gt;（a）以15 V的步骤和与栅电压从-60V。改变到60伏的输出特性（b）该传递特性，其同时显示日志（蓝线）和线性（黑线）的图在30 V弯曲前的PET基材上TCDAP单晶场效应晶体管（SCFET）栅极偏置漏源极-漏极偏压的函数（V DS）的电流。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig4large.jpg" target="_blank">请点击此处查看这个大版本数字。</a> <img alt="图5" src="/files/ftp_upload/54651/54651fig5.jpg" /> 图5. 弯曲实验的示意图。（ 一 ）向上方弯曲的状态，与周围的圆筒缠绕在器件部露出的基片的边缘，和（b）的向下弯曲站德，周围的圆筒包装基材。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图6" src="/files/ftp_upload/54651/54651fig6.jpg" /> 图6. 比较的TCDAP单一基于晶体-FET器件的传输特性。前后（ 一 ）向下弯曲及（b）向上弯曲，第一次和第四次到曲率半径R = 14.0Hz毫米。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig6large.jpg" target="_blank">请点击这里查看该图的放大版本。</a> <img alt="图7" src="/files/ftp_upload/54651/54651fig7.jpg" /> 图7 的第的传输特性的一个覆盖ÈTCDAP单个基于晶体的FET器件。对于（ 一 ）向下弯曲，以及（b）在不同的弯曲半径向上弯曲弯曲状态（R = 14.0Hz毫米，R =12.4毫米，R = 8.0Hz毫米，和R = 5.8Hz MM） 。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig7large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图8" src="/files/ftp_upload/54651/54651fig8.jpg" /> 图8. 测量迁移率作为TCDAP单个基于晶体的装置中的弯曲半径的函数（a）中向下弯曲。 （ 二 ）向上弯曲。 <a href="http://ecsource.jove.com/files/ftp_upload/54651/54651fig8large.jpg" target="_blank">请点击此处查看该图的放大版本。</a>

Watch this Scientific Journal Video about Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors at JoVE.com

Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

该原稿描述了一种有机单基于晶体的场效应晶体管，以保持对电子特性测量一个运作装置的弯曲加工。结果表明，在晶体中的分子间距，从而在电荷跳频速率，这是在柔性电子重要弯曲原因的变化。

弯曲对基于晶体的柔性有机单场效应晶体管的电气特性的影响

The charge transport in an organic semiconductor depends highly on the molecular packing in the crystal, which influences the electronic coupling ...

effect-bending-on-electrical-characteristics-flexible-organic-single

Nanyang Technological University

Research

JoVE Journal

Engineering

8.0K 次观看.  Academia Sinica. 该原稿描述了一种有机单基于晶体的场效应晶体管，以保持对电子特性测量一个运作装置的弯曲加工。结果表明，在晶体中的分子间距，从而在电荷跳频速率，这是在柔性电子重要弯曲原因的变化。 

视频: Effect of Bending on the Electrical Characteristics of Flexible Organic Single Crystal-based Field-effect Transistors

Concurrent Quantitative Conductivity and Mechanical Properties Measurements of Organic Photovoltaic Materials using AFM

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. Thus, understanding of spatial variations in composition as well as electrical properties of OPV materials is of paramount importance for moving PV technology forward.1,2 In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution. Currently, materials properties measurements performed using commercially available AFM-based techniques (PeakForce, conductive AFM) generally provide only qualitative information. The values for resistance as well as Young's modulus measured using our method on the prototypical ITO/PEDOT:PSS/P3HT:PC61BM system correspond well with literature data. The P3HT:PC61BM blend separates onto PC61BM-rich and P3HT-rich domains. Mechanical properties of PC61BM-rich and P3HT-rich domains are different, which allows for domain attribution on the surface of the film. Importantly, combining mechanical and electrical data allows for correlation of the domain structure on the surface of the film with electrical properties variation measured through the thickness of the film.

Organic photovoltaic (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale inhomogeneity of OPV materials affects performance of photovoltaic devices. In this paper, we describe a protocol for quantitative measurements of electrical and mechanical properties of OPV materials with sub-100 nm resolution.

并行定量的导电性和力学性能测试的有机光伏材料利用原子力显微镜

Organic photovoltaic  (OPV) materials are inherently inhomogeneous at the nanometer scale. Nanoscale  inhomogeneity of OPV materials affects performance ...

科研

工程学

Strain Sensing Based on Multiscale Composite Materials Reinforced with Graphene Nanoplatelets

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are proposed to create the electrical network in this work: (a) the incorporation of the nanoplatelets into the epoxy matrix and (b) the coating of the glass fabric with a sizing filled with the same nanoplatelets. Both types of multiscale composite materials, with an in-plane electrical conductivity of ~10-3 S/m, showed an exponential growth of the electrical resistance as the strain increases due to distancing between adjacent functionalized graphene nanoplatelets and contact loss between overlying ones. The sensitivity of the materials analyzed during this research, using the described procedures, has been shown to be higher than commercially available strain gauges. The proposed procedures for self-sensing of the structural composite material would facilitate the structural health monitoring of components in difficult to access emplacements such as offshore wind power farms. Although the sensitivity of the multiscale composite materials was considerably higher than the sensitivity of metallic foils used as strain gauges, the value reached with NH2 functionalized graphene nanoplatelets coated fabrics was nearly an order of magnitude superior. This result elucidated their potential to be used as smart fabrics to monitor human movements such as bending of fingers or knees. By using the proposed method, the smart fabric could immediately detect the bending and recover instantly. This fact permits precise monitoring of the time of bending as well as the degree of bending.

The integration of conductive nanoparticles, such as graphene nanoplatelets, into glass fiber composite materials creates an intrinsic electrical network susceptible to strain. Here, different methods to obtain strain sensors based on the addition of graphene nanoplatelets into the epoxy matrix or as a coating on glass fabrics are proposed.

基于多尺度复合材料的增强与石墨烯纳米片应变传感

The electrical response of NH2-functionalized graphene nanoplatelets composite materials under strain was studied. Two different manufacturing methods are ...

Sensing of Barrier Tissue Disruption with an Organic Electrochemical Transistor

The gastrointestinal tract is an example of barrier tissue that provides a physical barrier against entry of pathogens and toxins, while allowing the passage of necessary ions and molecules. A breach in this barrier can be caused by a reduction in the extracellular calcium concentration. This reduction in calcium concentration causes a conformational change in proteins involved in the sealing of the barrier, leading to an increase of the paracellular flux. To mimic this effect the calcium chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N&#39;,N&#39;-tetra acetic acid (EGTA) was used on a monolayer of cells known to be representative of the gastrointestinal tract. Different methods to detect the disruption of the barrier tissue already exist, such as immunofluorescence and&#160;permeability assays. However, these methods are time-consuming and costly and not suited to dynamic or high-throughput measurements. Electronic methods for measuring barrier tissue integrity also exist for measurement of the transepithelial resistance (TER), however these are often costly and complex. The development of rapid, cheap, and sensitive methods is urgently needed as the integrity of barrier tissue is a key parameter in drug discovery and pathogen/toxin diagnostics. The organic electrochemical transistor (OECT) integrated with barrier tissue forming cells has been shown as a new device capable of dynamically monitoring barrier tissue integrity. The device is able to measure minute variations in ionic flux with unprecedented temporal resolution and sensitivity, in real time, as an indicator of barrier tissue integrity. This new method is based on a simple device that can be compatible with high throughput screening applications and fabricated at low cost.

The Organic Electrochemical Transistor is integrated with live cells and used to monitor ion flux across the gastrointestinal epithelial barrier. In this study, an increase in ion flux, related to disruption of tight junctions, induced by the presence of the calcium chelator EGTA (ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetra acetic acid), is measured.

阻隔组织破坏与有机电化学晶体管传感

The gastrointestinal tract is an example of barrier tissue that provides a physical barrier against entry of pathogens and toxins, while allowing the ...

生物工程

Preparation of Liquid Crystal Networks for Macroscopic Oscillatory Motion Induced by Light

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous light irradiation. The photo-excitation of dopants that can quickly dissipate light into heat, coupled with anisotropic thermal expansion and self-shadowing of the film, gives rise to the self-sustained deformation. The oscillations observed are influenced by the dimensions and the modulus of the film, and by the directionality and intensity of the light. The system developed offers applications in energy conversion and harvesting for soft-robotics and automated systems.
The general method described here consists of creating free-standing liquid crystalline films and characterizing the mechanical and thermal effects observed. The molecular alignment is achieved using alignment layers (rubbed polyimide), commonly used in the display manufacturing industry. To obtain actuators with large deformation, the mesogens are aligned and polymerized in a splay/bend configuration, i.e., with the director of the liquid crystals (LCs) going gradually from planar to homeotropic through the film thickness. Upon irradiation, the mechanical and thermal oscillations obtained are monitored with a high-speed camera. The results are further quantified by image analysis using an image processing program.

The goal of the protocol is to create liquid crystalline polymer films that can mechanically oscillate under continuous light irradiation. We describe in great detail the conception of free-standing films, from the liquid crystal alignment method to the photo-actuation. The experimental protocol applied to prepare this material is broadly applicable.

光诱导的宏观振荡运动液晶网络的制备

A strategy based on doped liquid crystalline networks is described to create mechanical self-sustained oscillations of plastic films under continuous ...

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape method or individual WS2 nanotubes by dispersing the suspension of WS2 nanotubes. The selected samples have been fabricated into devices by the use of the electron beam lithography and electrolyte is put on the devices. We have characterized the electronic properties of the devices under applying the gate voltage. In the small gate voltage region, ions in the electrolyte are accumulated on the surface of the samples which leads to the large electric potential drop and resultant electrostatic carrier doping at the interface. Ambipolar transfer curve has been observed in this electrostatic doping region. When the gate voltage is further increased, we met another drastic increase of source-drain current which implies that ions are intercalated into layers of WS2 and electrochemical carrier doping is realized. In such electrochemical doping region, superconductivity has been observed. The focused technique provides a powerful strategy for achieving the electric-filed-induced quantum phase transition.

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating

Here, we present a protocol to control the carrier number in solids by using the electrolyte.

用电解质浇注法对 WS2纳米器件电子态的电场控制

A method of carrier number control by electrolyte gating is demonstrated. We have obtained WS2 thin flakes with atomically flat surface via scotch tape ...

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

基于范德华 Heteroepitaxy 的柔性铁电元件制备及测量方法

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due to their potential applications for future device technologies such as sensors and storage. However, conventional approaches, which usually utilize materials containing magnetic metal ions (or radicals), have a major problem: only a few materials have been found to show the coupling phenomena at room temperature. Recently, we proposed a new approach to achieve room-temperature magnetoelectrics. In contrast to conventional approaches, our alternative proposal focuses on a completely different material, a &#34;liquid crystal&#34;, free from magnetic metal ions. In such liquid crystals, a magnetic field can be utilized to control the orientational state of constituent molecules and the corresponding electric polarization through magnetic anisotropy of the molecules; it is an unprecedented mechanism of the magnetoelectric effect. In this context, this paper provides a protocol to measure ferroelectric properties induced by a magnetic field, that is, the direct magnetoelectric effect, in a liquid crystal. With the method detailed here, we successfully detected magnetically-tuned electric polarization in the chiral smectic C phase of a liquid crystal at room temperature. Taken together with the flexibility of constituent molecules, which directly affects the magnetoelectric responses, the introduced method will serve to allow liquid crystal cells to acquire more functions as room-temperature magnetoelectrics and associated optical materials.

In this report, we present a protocol to examine direct magnetoelectric effects, i.e., induction of ferroelectric polarization by applying magnetic fields, in liquid crystals. This protocol provides a unique approach, supported by the softness of liquid crystals, to achieve room-temperature magnetoelectrics.

液晶中磁调谐铁电极化的测量

Materials showing coupling phenomena between magnetism and (ferro)electricity, i.e., magnetoelectric effects, have attracted a great deal of attention due ...

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal

Smart viscoelastic materials that respond to specific stimuli are one of the most attractive classes of materials important to future technologies, such as on-demand switchable adhesion technologies, actuators, molecular clutches, and nano-/microscopic mass transporters. Recently it was found that through a special solid-liquid transition, rheological properties can exhibit significant changes, thus providing suitable smart viscoelastic materials. However, designing materials with such a property is complex, and forward and backward switching times are usually long. Therefore, it is important to explore new working mechanisms to realize solid-liquid transitions, shorten the switching time, and enhance the contrast of rheological properties during switching. Here, a light-induced crystal-liquid phase transition is observed, which is characterized by means of polarizing light microscopy (POM), photorheometry, photo-differential scanning calorimetry (photo-DSC), and X-ray diffraction (XRD). The light-induced crystal-liquid phase transition presents key features such as (1) fast switching of crystal-liquid phases for both forward and backward reactions and (2) a high contrast ratio of viscoelasticity. In the characterization, POM is advantageous in offering information on the spatial distribution of LC molecule orientations, determining the type of liquid crystalline phases appearing in the material, and studying the orientation of LCs. Photorheometry allows measurement of a material&#8217;s rheological properties under light stimuli and can reveal the photorheological switching properties of materials. Photo-DSC is a technique to investigate thermodynamic information of materials in darkness and under light irradiation. Lastly, XRD allows studying of microscopic structures of materials. The goal of this article is to clearly present how to prepare and measure the discussed properties of a photorheological material.

This protocol demonstrates the preparation of a photorheological material that exhibits a solid phase, various liquid crystalline phases, and an isotropic liquid phase by increasing temperature. Presented here are methods for measuring the structure-viscoelasticity relationship of the material.

扭曲弯曲的液晶的高对比度和快速光圈开关

Smart viscoelastic materials that respond to specific stimuli are one of the most attractive classes of materials important to future technologies, such ...

化学

The Effect of Anodization Parameters on the Aluminum Oxide Dielectric Layer of Thin-Film Transistors

Aluminum-oxide (Al2O3) is a low cost, easily processable and high dielectric constant insulating material that is particularly appropriate for use as the dielectric layer of thin-film transistors (TFTs). Growth of aluminum-oxide layers from anodization of metallic aluminum films is greatly advantageous when compared to sophisticated processes such as atomic layer deposition (ALD) or deposition methods that demand relatively high temperatures (above 300 &#176;C) such as aqueous combustion or spray-pyrolysis. However, the electrical properties of the transistors are highly dependent on the presence of defects and localized states at the semiconductor/dielectric interface, which are strongly affected by the manufacturing parameters of the anodized dielectric layer. To determine how several fabrication parameters influence the device performance without performing all possible combination of factors, we used a reduced factorial analysis based on a Plackett-Burman design of experiments (DOE). The choice of this DOE permits the use of only 12 experimental runs of combinations of factors (instead of all 256 possibilities) to obtain the optimized device performance. The ranking of the factors by the effect on device responses such as the TFT mobility is possible by applying analysis of variance (ANOVA) to the obtained results.

Anodization parameters for growth of the aluminum-oxide dielectric layer of zinc-oxide thin-film transistors (TFTs) are varied to determine the effects on the electrical parameter responses. Analysis of variance (ANOVA) is applied to a Plackett-Burman design of experiments (DOE) to determine the manufacturing conditions that result in optimized device performance.

阳极化参数对薄膜晶体管氧化铝介电层的影响

Aluminum-oxide (Al2O3) is a low cost, easily processable and high dielectric constant insulating material that is particularly appropriate for use as the ...

A Simple and Scalable Fabrication Method for Organic Electronic Devices on Textiles

Today, wearable electronics devices combine a large variety of functional, stretchable, and flexible technologies. However, in many cases, these devices cannot be worn under everyday conditions. Therefore, textiles are commonly considered the best substrate to accommodate electronic devices in wearable use. In this paper, we describe how to selectively pattern organic electroactive materials on textiles from a solution in an easy and scalable manner. This versatile deposition technique enables the fabrication of wearable organic electronic devices on clothes.

In this paper, we present a protocol to selectively deposit organic materials on textiles, which allows for the direct integration of organic electronic devices with wearables. The fabricated devices can be fully integrated in textiles, respecting their mechanical appearance and enabling sensing capabilities.

关于纺织品有机电子设备的简单和可扩展的制作方法

Today, wearable electronics devices combine a large variety of functional, stretchable, and flexible technologies. However, in many cases, these devices ...