这项工作由美国陆军研究办公室在赠款 W911NF-15-1-0414 下支持。

1. 自制努森细胞的研制
<ol><li>
准备努森单元的组件
	<ol>
<li>购买 cf 法兰基电源馈 (2.75 "CF, 4 针不锈钢)。钻两个螺纹孔通过馈, 在十字点之间的一个直径 1.30 "线和它的周长。</li>
		<li>准备一个玻璃管 (0.315 "外径 (OD), 2.50" 长度)。</li>
		<li>采购薄铜板 (99.9%) 与 0.005 "厚度。用剪刀将一张纸切成 7.5 "L x 5.0" W 的尺寸, 然后将其卷曲到带有 1.45 "手动直径" 的空心圆柱形通盾(图 1a)。</li>
		<li>将 K 型热电偶 (铬镍/alumel) 与 0.005 "直径切割 3" 长度为铬镍和 alumel 线。剥离绝缘层约 0.5 "长度从两端的两条电线。</li>
		<li>将0.01 英寸直径的钨线 (99.95%) 剪成大约60英寸的长度。线圈它到一个春天形状与直径 0.315 "通过紧紧包裹它在玻璃管的一个可比较的直径的杆附近。</li>
		<li>购买陶瓷片。准备一个合适的长方体件, 中间有一个孔, 适合玻璃的尺寸 (5 在图 1b)。</li>
		<li>切割2标准钢螺纹 0.10 "直径杆到 7" 长度通过捆扎和锯与车床机器。</li>
		<li>剪一个软, 0.01 "直径铜线到大约 30" 长度使用剪刀。</li>
		<li>准备4空心铜棒与 0.094 "外径直径通过切割三杆到 2" 长度, 和一个杆到 4 "长度使用侧刀。</li>
	</ol>
</li>
	<li>
在努森细胞中组装这些碎片
	<ol>
<li>清除步骤1.1 中提到的所有组件, 使用丙酮中的42赫超声波清洗30分钟。</li>
		<li>在电源馈的 CF 法兰的钻孔中安装2标准钢螺纹棒。 注意: 孔是螺纹的 (7 在图 1b) 中。</li>
		<li>在 CF 法兰式电源馈的4个针脚的顶部安装4空心铜棒的下半部分, 办法是将 pin 插入空心铜棒中, 并由侧面刀具 (6 in图 1b) 进行固定。</li>
		<li>将陶瓷片安装在 2.5 "高从螺纹棒底部与软铜线的位置。 注: 此片断将支持玻璃管在以下步骤 (5 在图 1b)。</li>
		<li>将玻璃管滑入卷曲的钨弹簧中。将玻璃管的底部挤压成陶瓷片的孔。使用软铜线将玻璃管的顶端保持在螺纹棒的顶端 (3 和4在图 1b) 中。</li>
		<li>把弹簧的上端夹在较长的铜杆上, 定义为 a. 把弹簧的底部握成一个较短的铜棒, 定义为 b (A 和 B 在图 1b)。</li>
		<li>将铬镍和 alumel 线的一个去皮端拧在一起 (2 in 图1b)。</li>
		<li>定位拧紧的接头端, 使其紧密接触玻璃管的外部底部。在陶瓷片的帮助下固定它。</li>
		<li>将铬镍导线的另一去皮端夹入左侧2条较短的铜棒中, 定义为 c 把 alumel 线的另一端去皮到左短铜杆中, 定义为 D (C 和 D在图1b)。</li>
		<li>将卷曲的铜空心圆柱形通盾放在 CF 法兰电源馈上(图 1a)。</li>
	</ol>
</li>
</ol>2. 在自制的努森细胞中准备 C60源
<ol><li>在自制的努森单元格中加载 C60源。<ol>
<li>将约50毫克的 C60粉末 (99.5% 纯度) 加载到自制努森细胞的玻璃管中。 注: 精度超过1毫克的粉末质量是不必要的。</li>
		<li>将努森单元格装回加载锁的一个分支上。</li>
	</ol>
</li>
	<li>泵入负载锁。<ol>
<li>打开泵上的负载锁。首先打开水阀, 冷却涡轮泵, 然后打开风扇冷却机械泵。然后打开机械泵, 最后打开涡轮泵。</li>
		<li>检查负载锁中的压力, 等待大约10小时。 注: 涡轮泵出口的压力应为 6.0 x 10-2毫巴。</li>
		<li>打开安装在负载锁中的离子表以降低压力 (通常低于 10-6毫巴)。</li>
		<li>检查负载锁中的压力: 在10小时泵浦后, 压力应在 10-8毫巴的范围内。</li>
	</ol>
</li>
	<li>在自制的努森单元格中退火 C60源。<ol>
<li>将 C60源在自制的努森单元中逐渐退火 (1.5 °c/分钟), 在250°c 为 2 h 进行脱气, 方法是在 CF 法兰电源馈的两个针脚上连接电源, 连接到卷曲的钨弹簧上。</li>
		<li>将退火温度提高到300摄氏度, 高于沉积温度 (270 摄氏度)。</li>
		<li>退火在300°c 为0.5 小时进一步脱气。</li>
		<li>将温度降低到270摄氏度以进行沉积。</li>
	</ol>
</li>
</ol>3. 在特高压室中制备原子清洁石墨烯
<ol><li>将石墨烯 (在铜箔上) 从样品存储传送带转到 STM 系统超高真空制备室的退火板 (在超高真空下制备和退火样品的特殊位置)。</li>
	<li>将石墨烯基体在制备腔内的低 10-10毫巴的基压下退火, 逐步将温度升高到400摄氏度。</li>
	<li>等待12小时, 去除石墨烯表面的残余杂质。</li>
	<li>将石墨烯基体的退火温度逐渐降低到室温。</li>
</ol>4. 使用自制的努森细胞在负载锁中将 C 60存入石墨烯基体上
<ol><li>将石墨烯基体转移到负载锁上。<ol>
<li>在准备室的转移位置安排板材。在原子清洁石墨烯和 C60源就绪后, 将原子清洁石墨烯转移到沉积 C60的负载锁中。</li>
		<li>在负载锁和准备室之间打开阀门。</li>
		<li>用装车工具将石墨烯基体从准备室的板上转移到负载锁。</li>
		<li>将石墨烯基体朝下 (C60来自下面的源)。</li>
	</ol>
</li>
	<li>将 C60存入石墨烯衬底上。 注: C60分子从自制的努森细胞转移到石墨烯基板, 在270摄氏度。<ol>
<li>等待1分钟的沉积速率为0.9 单层/分钟。</li>
		<li>将 C60/石墨烯样品转移回制备室。</li>
	</ol>
</li>
</ol>5. 准备在 STM 主腔内测量的 C 60 /石墨烯样品
<ol><li>将 C60/石墨烯样品退火至150摄氏度, 在超高真空制备室中, 2 h 的速率为3.1 摄氏度/分钟。</li>
	<li>用 stm 在 stm 主腔中扫描 C60/石墨烯样品。</li>
	<li>将 C60/石墨烯样品退火至210°c, 其速率为3.1 摄氏度/分钟, 为 2 h。</li>
	<li>用 STM 扫描 C60/石墨烯样品。</li>
</ol>

<ol>
	<li>Gutzler, R., Heckl, W. M., Lackinger, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Combination+of+a+Knudsen+effusion+cell+with+a+quartz+crystal+microbalance:+In+situ+measurement+of+molecular+evaporation+rates+with+a+fully+functional+deposition+source.">Combination of a Knudsen effusion cell with a quartz crystal microbalance: In situ measurement of molecular evaporation rates with a fully functional deposition source.</a> Review of Scientific Instruments. 81, 015108 (2010).</li><li>de Barros, A. L. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+simple+experimental+arrangement+for+measuring+the+vapour+pressures+and+sublimation+enthalpies+by+the+Knudsen+effusion+method:+Application+to+DNA+and+RNA+bases.">A simple experimental arrangement for measuring the vapour pressures and sublimation enthalpies by the Knudsen effusion method: Application to DNA and RNA bases.</a> Nuclear Instruments &amp; Methods in Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment. 560, (2006).</li><li>Shukla, A. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Versatile+UHV+compatible+Knudsen+type+effusion+cell.">Versatile UHV compatible Knudsen type effusion cell.</a> Review of Scientific Instruments. 75, 4467 (2004).</li><li>Cho, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structural+and+Electronic+Decoupling+of+C60+from+Epitaxial+Graphene+on+SiC.">Structural and Electronic Decoupling of C60 from Epitaxial Graphene on SiC.</a> Nano Letters. 12, 3018 (2012).</li><li>Jung, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Atomically+resolved+orientational+ordering+of+C60+molecules+on+epitaxial+graphene+on+Cu(111).">Atomically resolved orientational ordering of C60 molecules on epitaxial graphene on Cu(111).</a> Nanoscale. 6 (111), 11835 (2014).</li><li>Li, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Self-assembly+of+C60+monolayer+on+epitaxially+grown,+nanostructured+graphene+on+Ru(0001)+surface.">Self-assembly of C60 monolayer on epitaxially grown, nanostructured graphene on Ru(0001) surface.</a> Applied Physics Letters. 100 (0001), 013304 (2012).</li><li>Lu, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Using+the+Graphene+Moire+Pattern+for+the+Trapping+of+C60+and+Homoepitaxy+of+Graphene.">Using the Graphene Moire Pattern for the Trapping of C60 and Homoepitaxy of Graphene.</a> Acs Nano. 6, 944 (2012).</li><li>Zhou, H. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+imaging+of+intrinsic+molecular+orbitals+using+two-dimensional,+epitaxially-grown,+nanostructured+graphene+for+study+of+single+molecule+and+interactions.">Direct imaging of intrinsic molecular orbitals using two-dimensional, epitaxially-grown, nanostructured graphene for study of single molecule and interactions.</a> Applied Physics Letters. 99, 153101 (2011).</li><li>Belaish, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Spin+Cast+Thin-Films+of+Fullerenes+and+Fluorinated+Fullerenes+-+Preparation+and+Characterization+by+X-Ray+Reflectivity+and+Surface+Diffuse-X-Ray+Scattering.">Spin Cast Thin-Films of Fullerenes and Fluorinated Fullerenes - Preparation and Characterization by X-Ray Reflectivity and Surface Diffuse-X-Ray Scattering.</a> Journal of Applied Physics. 71, 5248 (1992).</li><li>Bezmel'nitsyn, V. N., Eletskii, A. V., Okun', M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fullerenes+in+solutions.">Fullerenes in solutions.</a> Uspekhi Fizicheskikh Nauk. 168, 1195 (1998).</li><li>Ma, D. N., Sandoval, S., Muralidharan, K., Raghavan, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+surface+preparation+of+copper+on+spin-coating+driven+self-assembly+of+fullerene+molecules.">Effect of surface preparation of copper on spin-coating driven self-assembly of fullerene molecules.</a> Microelectronic Engineering. 170, 8 (2017).</li><li>Chen, C. H., Zheng, H. S., Mills, A., Heflin, J. R., Tao, C. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+Evolution+of+Quasi-one-dimensional+C60+Nanostructures+on+Rippled+Graphene.">Temperature Evolution of Quasi-one-dimensional C60 Nanostructures on Rippled Graphene.</a> Scientific Reports. 5, 14336 (2015).</li></ol>

我们没有什么可透露的。

本协议所描述的技术设计用于有机材料和其他高蒸气压材料的热沉积。这些技术可与超高真空系统集成, 具有样品制备区域, 能够支持分子蒸发和热退火。本实验的目的是在石墨烯基体上沉积 c60分子, 并研究 c60的自组装和热效应。
该方法的好处是, 它提供了一个超级干净的样品时, 与其他薄膜制备方法, 如自旋涂层。与化学气相沉积 (CVD) 等复杂技术相比, 这种物理热蒸发更容易实现, 适合稳定的原子和分子沉积。原子和分子分辨率成像需要观察 C60/石墨烯混合纳米结构。本博览会使用 STM。在整个过程中, 通过脱气和退火来保持基体和 C60源的纯度是至关重要的。适当的后沉积退火是获得1D 和 quasi-1D 纳米结构的关键, 因为这一技术在不同的热条件下利用 C60表面流动性的可变性质。
STM 测量表明, 由物理热沉积法合成的 C60/石墨烯样品是原子清洁的。负载锁中的空间设计为非常有限, 在相当短的时间内实现超高真空。分子沉积需要完成在这样一个小空间, 一个自制的努森细胞变得必要。自制的努森细胞蒸发器安装在负载锁室, 可以单独烘烤, 这也有助于改变分子或重填蒸发器12。该自制努森细胞的最高沉积温度为450摄氏度, 由 CF 法兰功率馈确定。将 c60源在自制的努森单元格中加成300摄氏度是至关重要的, 以保证 c60在270°c 时的纯度。在分子沉积之前退火石墨烯基体也非常重要, 这样在沉积开始时它就处于最干净的状态。一个二进制系统也可以通过增加一个自制的努森细胞蒸发器在第一个相反的一侧。

本协议解释如何在石墨烯上沉积和操作 c60分子, 这样可以实现1D 和 quasi-1D C60链结构。这项实验的技术是为了解决需要引导考察到理想的配置, 而不必依赖手动操作, 这是缓慢的, 并可能需要很大的努力。这里描述的过程依赖于使用一个高真空系统与样品准备区域能支持分子沉积和热退火样品。STM 是用来表征样品, 但其他分子分辨率技术可以应用。
努森细胞内分子的热蒸发是制备薄膜的一种高效、清洁的方法。在本协议中, 努森单元用于将 C60分子蒸发到石墨烯基板上。此努森电池蒸发器主要由石英管、加热灯丝、热电偶线和贯穿件可1、2、3组成.石英管用于容纳分子, 钨灯丝通过应用电流加热石英管中的分子, 热电偶导线用于测量温度。实验中, 通过对努森细胞中温度源的调节, 控制了沉积速率。热电偶导线附着在石英管的外壁上, 因此通常测量外部壁的温度, 这与分子源所在细胞内的温度稍有不同。为了获得石英管的精确温度, 我们用两个热电偶装置进行了标定, 以测量管内外的温度, 并记录了温度差。这样, 我们就可以更精确地控制在分子蒸发实验中使用连接到石英管外的热电偶线的温度。由于少量的升华分子将在一个较低的压力下的气态相, 当分子被蒸发, 通常有一个相关的压力变化。因此, 我们仔细地监视负载锁中压力的变化。
该蒸发器可用于存放各种分子源, 如 c60、c70、硼酞菁染料氯化物、Ga、Al 和Hg4、5、6、7、8。与其他薄膜制备技术相比, 自旋铸造9,10,11, 高真空中的热蒸发更清洁和多功能, 因为没有溶剂需要证言。此外, 沉积前的脱气过程提高了源的纯度, 消除了可能的杂质。

<table>
	<tbody>
		<tr>
			<td>CF Flanged power feedthrough</td>
			<td>Kurt J. Lesker</td>
			<td>EFT0042033</td>
			<td></td>
		</tr>
		<tr>
			<td>Copper sheets</td>
			<td>Alfa Aesar</td>
			<td>7440-50-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouple chromel/alumel wires</td>
			<td>Omega Engineering</td>
			<td>ST032034/ST080042</td>
			<td></td>
		</tr>
		<tr>
			<td>Tungsten wires</td>
			<td>Alfa Aesar</td>
			<td>7440-33-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless steel rods</td>
			<td>McMaster-Carr</td>
			<td>95412A868</td>
			<td></td>
		</tr>
		<tr>
			<td>Copper wires</td>
			<td>McMaster-Carr</td>
			<td>8873K28</td>
			<td></td>
		</tr>
		<tr>
			<td>Hollow copper rods</td>
			<td>McMaster-Carr</td>
			<td>7190K52</td>
			<td></td>
		</tr>
		<tr>
			<td>C60</td>
			<td>MER Corporation</td>
			<td>MR6LP</td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation and characterization of c60/graphene hybrid nanostructures

高真空环境下的物理热沉积是制备石墨烯上新型分子纳米结构的一种清洁、可控的方法。我们提出了在波纹石墨烯上沉积和被动操作 C60分子的方法, 它推动了实现涉及 1D C60/石墨烯混合结构的应用。本博览会所采用的技术是针对高真空系统的, 其制备区域能够支持分子沉积以及样品的热退火。我们专注于 C60在低压沉积使用一个自制的努森细胞连接到扫描隧穿显微镜 (STM) 系统。通过控制努森细胞的温度和沉积时间来调节沉积分子的数量。一维 (1D) C60链结构, 其宽度为三个分子, 可通过对实验条件的调整来制备。C60分子的表面流动性随退火温度的增加而增大, 使它们能够在波纹石墨烯的周期性电位内移动。使用此机制, 可以控制 1D C60链结构的过渡到六角封闭包装 quasi-1D 条纹结构。

蒸发后, 新沉积的 C60的石墨烯退火为 2 h 的150摄氏度。图 2a中的大型 STM 映像显示了此初始退火过程后发现的特性 quasi-1D C60链结构。在图 2b中进行更仔细的检查, 可显示此1D 结构的详细信息, 其中每个明亮的球面凸起表示一个单一的 C60分子。通常, 1D 链作为分子和三分子 c 60 链出现, 其平均值为 c 60-C 60 距离 1.00 @ 0.01 nm, 表示 c 60 分子以六角封闭的方式排列. 图 2c中对应于图 2b中的虚线绿线的线条配置文件显示了 C60链之间的清晰分隔, 其中第二个和第三个峰值位于相邻链上的最近邻分子。根据观察, 链子完全地存在作为分子或三分子行以分子链子频繁地发生两次象三分子链子。正如在高分辨率 STM 图像中所观察到的, 链在 3-2-2 或 2-3-2 的方式下排列良好。在一个链中可能会出现一些结点, 三分子段可以跳到分子排列, 反之亦然。
quasi-1D C60链的生长是由下面的石墨烯基体引起的。原子化清洁石墨烯基板的高分辨率 STM 图像 (图 1c) 显示波纹结构。这种定义良好的线性周期调制导致 C60分子形成 quasi-1D 链。样品随后退火在210°c 为 2 h 为了调查热影响对 C60/石墨烯1D 纳米结构。在较高的温度下退火会增加 C60分子的表面流动性, 使它们能够自组装成更紧凑、六边形的封闭 quasi-1D 条纹结构, 如图 3a所示。这些结构沿与 C60链相同的方向定向, 并观察到每条条纹的宽度变化在3和8分子之间, 如图 3b所示。最常见的条纹宽度为六 C60行, 出现45% 的时间, 而5行条纹是第二个最有可能的条纹结构。在这个结构中, 没有分隔相邻条纹的空间。与温和退火的 C60链结构明显不同的是, 条纹不是在单个平坦的平台上形成的, 而是在交错的窄阶上, 显示为近直和平行的台阶边缘 (图 3b, C)。两行在每一步边缘的边界, 一个在上层露台和一个在较低的露台, 假设一个更密集的安排相对于彼此, 只有一个横向之间的行间距为 0.75 0.01 nm。这个安排大概容纳在更高的温度退火以后形成的底层梯田。在露台平面上, c60分子仍然保持一个封闭的模式, 其分子间间距特征为 c60-c60。位于上层平台上台阶边缘附近的 c60行似乎比同一平台上其他 C60行高约0.5 Å;这可能是由于本地电子环境不同, 如图 3b、c所示。类似于以前的链结构, 有相邻的条纹连接。为了更系统地比较这两个不同的结构, 我们使用3D 模型来说明它们。图 4a, c是 c60链的示意图模型的顶部和侧面视图, 分别为 c60分子 (暗绿色球体) 和石墨烯基板 (小蓝色球体) 的蜂窝结构。在这里, 链结构的单位被定义为一个分子单元 (链加上一个考虑链间间距) 加上相邻的三分子单元。3D 模型清楚地显示一个单位的大小为 5.08 @ 0.02 nm。相邻链之间的较大间隙间距 (1.23 nm) 标记在图 4a、c中。图 4b中,d显示了6行条纹结构的3D 示意图模型。两个相邻的 C60条带之间的行间距越窄, 在图 4b中标记为 0.75 nm, 这比典型的六角封闭填充结构小。这些典型的6行条纹的横向周期性为 5.08 0.02 nm, 几乎完全等于链结构的单位大小的横向间距12。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57257/57257fig1.jpg"> 图 1.自制的努森细胞和原子化解析的石墨烯基体的 STM 图像.(a) 自制的努森细胞与铜壳。(b) 自制努森细胞的详细结构, 显示铜壳内部的主要成分。1是 CF 法兰, 2 是热电偶丝, 3 是 W 加热灯丝, 4 是玻璃管, 5 是陶瓷片, 6 是空心铜棒 (A、B、C、D), 7 是支撑杆, 8 是馈。(c) 原子解析的扫描石墨烯表面的 STM 地形图像12。图 1c已从12中修改。<a href="/files/ftp_upload/57257/57257fig1large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/57257/57257fig2.jpg"> 图 2.退火后的 C 60 链的 STM 映像, 在150摄氏度之后.(a) C60在石墨烯上形成有序的1D 链, 比单个链大得多 (vs = 2.255 V, I = 0.300 nA)。(b) C60纳米结构的分子分辨率 STM 图像, 显示只有分子或三分子链的出现。链中的分子间间距为 1.0 nm, 而相邻的 c60行的中心之间的距离属于相邻链 1.23 nm, 这比在紧密封装的 C60中 0.87 nm 的行之间的距离大得多。结构 (I = 0.500 nA, Vs = 1.950 V)。(c) 显示在 (b)12中沿虚线绿线的相邻链之间的分子间距离和间隙的线轮廓。此数字已从12中修改。<a href="/files/ftp_upload/57257/57257fig2large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/57257/57257fig3.jpg"> 图 3.在将退火温度提高到210摄氏度后, 在石墨烯上自组装准六角封闭 1D C60条纹结构.(a) STM 图像, 显示沿同一轴方向 (I = 0.200 nA, Vs = 2.200 V) 的准六边形闭合封装 C60 1D 条纹。(b) C60 1D 条纹的高分辨率 STM 图像 (I = 0.200 nA, Vs = 2.400 V)。(c) 显示在 (b)12中沿虚线绿线的两个露台上的六角闭合包装 c60 1D 条纹的线条配置文件。此数字已从12中修改。<a href="/files/ftp_upload/57257/57257fig3large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/57257/57257fig4.jpg"> 图 4.示意图模型.c60链和条纹的示意图模型, 将石墨烯描绘成较小的、底层的蓝色球体和 c60分子作为暗绿色、空间填充球体。(a, c)分子和三分子 C 60 链在石墨烯上的顶部和侧面视图.(b, d)具有6行宽度12的典型 C60条带的顶部和侧面视图。此数字已从12中修改。<a href="/files/ftp_upload/57257/57257fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>

Watch this Scientific Journal Video about Preparation and Characterization of C60/Graphene Hybrid Nanostructures at JoVE.com

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

C 型60/石墨烯混合纳米结构的制备与表征

在这里, 我们提出了一个协议, 以制造的 C60/石墨烯混合纳米结构的物理热蒸发。特别是, 适当地操纵沉积和退火条件, 可以控制在波纹石墨烯上创建1D 和准 1D C60结构。

Physical thermal deposition in a high vacuum environment is a clean and controllable method for fabricating novel molecular nanostructures on graphene. We ...

preparation-and-characterization-of-c60graphene-hybrid-nanostructures

Nanyang Technological University

Research

JoVE Journal

Chemistry

Preparation and Characterization of C60/Graphene Hybrid Nanostructures

9.4K 次观看.  Virginia Tech. 在这里, 我们提出了一个协议, 以制造的 C60/石墨烯混合纳米结构的物理热蒸发。特别是, 适当地操纵沉积和退火条件, 可以控制在波纹石墨烯上创建1D 和准 1D C60结构。

视频: Preparation and Characterization of C60/Graphene Hybrid Nanostructures

Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, have high porosity, high surface-to-volume and strength-to-weight ratio. Unfortunately, common approaches for preparation of metallic nanostructures render materials with highly disordered architecture, which might have an adverse effect on their mechanical properties. Block copolymers have the ability to self-assemble into ordered nanostructures and can be applied as templates for the preparation of well-ordered metal nanofoams. Here we describe the application of a block copolymer-based supramolecular complex - polystyrene-block-poly(4-vinylpyridine)(pentadecylphenol) PS-b-P4VP(PDP) - as a precursor for well-ordered nickel nanofoam. The supramolecular complexes exhibit a phase behavior similar to conventional block copolymers and can self-assemble into the bicontinuous gyroid morphology with two PS networks placed in a P4VP(PDP) matrix. PDP can be dissolved in ethanol leading to the formation of a porous structure that can be backfilled with metal. Using electroless plating technique, nickel can be inserted into the template&#39;s channels. Finally, the remaining polymer can be removed via pyrolysis from the polymer/inorganic nanohybrid resulting in nanoporous nickel foam with inverse gyroid morphology.

This article describes the preparation of well-ordered nickel nanofoams via electroless metal deposition onto nanoporous templates obtained from self-assembled diblock copolymer based supramolecules.

Gyroid镍纳米结构的嵌段共聚物超分子

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, ...

科研

化学

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid phase by using combinatorial chemistry. One of the most well studied classes of peptidomimetics is peptoids. Peptoids are easy to synthesize and have been shown to be proteolysis-resistant and cell-permeable. Over the past decade, many useful protein ligands have been identified through screening of peptoid libraries. However, most of the ligands identified from peptoid libraries do not display high affinity, with rare exceptions. This may be due, in part, to the lack of chiral centers and conformational constraints in peptoid molecules. Recently, we described a new synthetic route to access peptide tertiary amides (PTAs). PTAs are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. With side chains on both &#945;-carbon and main chain nitrogen atoms, the conformation of these molecules are greatly constrained by sterical hindrance and allylic 1,3 strain. (Figure 1) Our study suggests that these PTA molecules are highly structured in solution and can be used to identify protein ligands. We believe that these molecules can be a future source of high-affinity protein ligands. Here we describe the synthetic method combining the power of both split-and-pool and sub-monomer strategies to synthesize a sample one-bead one-compound (OBOC) library of PTAs.

Peptide tertiary amides (PTAs) are a superfamily of peptidomimetics that include but are not limited to peptides, peptoids and N-methylated peptides. Here we describe a synthetic method which combines&#160;both split-and-pool and sub-monomer strategies to synthesize a one-bead one-compound library of PTAs.

分裂和池合成及肽叔酰胺图书馆表征

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

功能化的合成与表征金属 - 有机骨架

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

Preparation and Characterization of SDF-1&#945;-Chitosan-Dextran Sulfate Nanoparticles

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under appropriate conditions. The glycan nanoparticles are useful carriers for protein factors, which facilitate the in vivo delivery of the proteins and sustain their retention in the targeted tissue. The glycan polyelectrolyte complexes are also ideal for protein delivery, as the incorporation is carried out in aqueous solution, which reduces the likelihood of inactivation of the proteins. Proteins with a heparin-binding site adhere to dextran sulfate readily, and are, in turn, stabilized by the binding. These particles are also less inflammatory and toxic when delivered in vivo. In the protocol described below, SDF-1&#945; (Stromal cell-derived factor-1&#945;), a stem cell homing factor, is first mixed and incubated with dextran sulfate. Chitosan is added to the mixture to form polyelectrolyte complexes, followed by zinc sulfate to stabilize the complexes with zinc bridges. The resultant SDF-1&#945;-DS-CS particles are measured for size (diameter) and surface charge (zeta potential). The amount of the incorporated SDF-1&#945; is determined, followed by measurements of its in vitro release rate and its chemotactic activity in a particle-bound form.

The objective of this protocol is to incorporate SDF-1&#945;, a stem cell homing factor, into dextran sulfate-chitosan nanoparticles. The resultant particles are measured for their size and zeta potential, as well as the content, activity, and in vitro release rate of SDF-1&#945; from the nanoparticles.

SDF-1α - 壳聚糖硫酸葡聚糖纳米粒子的制备与表征

Chitosan (CS) and dextran sulfate (DS) are charged polysaccharides (glycans), which form polyelectrolyte complex-based nanoparticles when mixed under ...

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar concentration forming hydrophobic cores surrounded by hydrophilic shells in aqueous environments. The core of these micelles can be utilized to load hydrophobic, poorly water soluble drugs like docetaxel (DTX) and everolimus (EVR). Systematic characterization of the micelle structure and drug loading capabilities are important before in vitro and in vivo studies can be conducted. The goal of the protocol described herein is to provide the necessary characterization steps to achieve standardized micellar products. DTX and EVR have intrinsic solubilities of 1.9 and 9.6 &#181;g/ml respectively Preparation of these micelles can be achieved through solvent casting which increases the aqueous solubility of DTX and EVR to 1.86 and 1.85 mg/ml, respectively. Drug stability in micelles evaluated at room temperature over 48 hr indicates that 97% or more of the drugs are retained in solution. Micelle size was assessed using dynamic light scattering and indicated that the size of these micelles was below 50 nm and depended on the molecular weight of the polymer. Drug release from the micelles was assessed using dialysis under sink conditions at pH 7.4 at 37 oC over 48 hr. Curve fitting results indicate that drug release is driven by a first order process indicating that it is diffusion driven.

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

制备及个体表征和多载药物理截留聚合物胶束

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

合成，表征和混合金/硫化镉和Au / ZnS核/壳纳米颗粒功能化

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

超分子胶体的合成与表征

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Low-energy Cathodoluminescence for (Oxy)Nitride Phosphors

Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and flexibility of their emission properties can be achieved by controlling their composition and dopants. However, a lot of work is still required to improve their properties and to reduce the production cost. A possible approach is to correlate the luminescence properties of the Sialon particles with their local structural and chemical environment in order to optimize their growth parameters and find novel phosphors. For such a purpose, the low-voltage cathodoluminescence (CL) microscopy is a powerful technique. The use of electron as an excitation source allows detecting most of the luminescence centers, revealing their luminescence distribution spatially and in depth, directly comparing CL results with the other electron-based techniques, and investigating the stability of their luminescence properties under stress. Such advantages for phosphors characterization will be highlighted through examples of investigation on several Sialon phosphors by low-energy CL.

Low-energy Cathodoluminescence for OxyNitride Phosphors

An excellent chemical and luminescence stabilities of (oxy)nitride phosphors present it as an promising alternative to currently used sulfide and oxide phosphors. In this paper, we present the way to investigate its local luminescence properties using low-energy cathodoluminescence (CL).

低能量的阴极射线（氧）氮化物荧光粉

Nitride and oxynitride (Sialon) phosphors are good candidates for the ultraviolet and visible emission applications. High performance, good stability and ...

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents. Specifically, the increase in local concentration of the paramagnetic species results in a higher signal contrast. Furthermore, this CA provides a longer tissue retention time due to its high molecular weight and size. Here, we demonstrate a convenient procedure for the preparation of macromolecular MRI contrast agents based on poly(amidoamine) (PAMAM) dendrimers with monomacrocyclic DOTA-type chelators (DOTA &#8211; 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate). The chelating unit was appended by exploiting the reactivity of the isothiocyanate (NCS) group towards the amine surface groups of the PAMAM dendrimer to form thiourea bridges. Dendrimeric products were purified and analyzed by means of nuclear magnetic resonance spectroscopy, mass spectrometry, and elemental analysis. Finally, high resolution MR images were recorded and the signal contrasts obtained from the prepared dendrimeric and the commercially available monomeric agents were compared.

Preparation and In Vitro Characterization of Dendrimer-based Contrast Agents for Magnetic Resonance Imaging

This protocol describes the preparation and characterization of a dendrimeric magnetic resonance imaging (MRI) contrast agent that carries cyclen-based macrocyclic chelates coordinating paramagnetic gadolinium ions. In a series of MRI experiments in vitro, this agent produced an amplified MRI signal when compared to the commercially available monomeric analogue.

制备及<em&gt;体外</em&gt;磁共振成像基于树状大分子造影剂的表征

Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance ...

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

上成膜钙钛矿型混合制造方法，电子结构和太阳能电池性能的影响

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...