它承认艺术和科学和教务长的Concordia大学办公室的学院院长办公室支持这项研究的乐趣。 作者要感谢GA克罗斯比他对本次调查的许多贡献。

1.样品制备和装载的低温光谱<ol><li>制备〜3毫升发光发色团的〜10 -3 -10 -4 M溶液在适当的溶剂。 注意:虽然许多溶剂，可以使用水和各种醇溶剂（ 例如 ，乙醇，乙醇/甲醇的混合物，乙二醇，和甘油）提供的溶解性和表面张力特性的用于低温工作的良好组合。 </li><li>通过加捻裸铜线的长度~0.4毫米直径围绕钉制备样品环或螺旋，得到单个环路〜3毫米直径后跟〜30毫米编织铜线直线长度。 </li><li>冲洗用95％的乙醇样品环以除去手指油和其它污染物并晾干。以确保环的清洁度，第一冲洗用硝酸，第二用蒸馏水，最后用乙醇。 </li><li>通过浸渍第加载样品溶液到样品环路Ë循环到样品溶液（步骤1.1）的溶液中，让表面张力保持在循环中的溶液的薄膜。 </li><li>马上浸装载样品环到液氮冷冻和稳定的循环，注意用眼保护（护目镜）和手部防护（手套）薄膜样品溶液。 </li></ol> 2.热电偶准备，调整和设置<ol><li>通过在两个铜 - 康铜结从非绝缘0.4毫米直径的铜导线的两个长度和0.4毫米直径的非绝缘康铜（铜镍合金）线之一长度制备的铜 - 康铜（T型）热电偶:将试样结和一个标准参比端（0 ℃的冰/水混合物）。 注意:虽然结可银焊接在一起，它是完全令人满意的扭转铜和康铜导线在一起以形成结。 <ol><li>夹紧铜和康铜导线磕磕碰碰呃与一〜90°角，尖嘴钳。而在两根电线拉牢，紧贴编织在一起了五六个圈。 </li></ol></li><li>安排所有热电偶导线所以他们不会比在两路口以外的任何点触摸。如果热电偶导线覆盖有薄绝缘涂层，它们可能接触并且比结其他点。 <ol><li>当使用绝缘热电偶电线，刮掉在形成所述结和所述电触点与所述电压表端子的导线的端部绝缘。小心检查导线上的绝缘材料不发光。通过放置在样品环一小片绝缘线，激发样品与所选择的波长的光，并寻找一个发射信号时，没有样品存在测试热电偶导线绝缘作为杂散发光的潜在来源。 </li></ol></li><li>从SAM连接两根铜热电偶导线PLE和参考路口高阻51/2位数字电压表的输入端。 </li><li>放置无论是在0℃的水/冰浴的样品和参考结和零电压表。 </li><li>对准装载样品环，并在液氮充满光学杜瓦热电偶的样本的结到适当的高度和激发光光束的方向一致。保持热电偶结和样品环路并拢尽可能和正好在杜瓦同一高度。 </li></ol> 3.一般机械支撑和样品环的对齐和热电偶结点在光学杜瓦<ol><li>要对齐并保持在光学杜瓦所需的高度样品环，通过张贴小电器鳄鱼夹到5毫米直径×30毫米长木榫准备一个可调节高度的固定夹。 <ol><li>在适合snugl软木塞钻孔稍微较小直径大于5毫米ý到光杜瓦的顶部。夹住鳄鱼夹样品环的编织线部分，然后在软木塞向上或向下滑动销实现杜瓦所需的样品高度。 </li></ol></li><li>为了在光学杜瓦所需的高度对齐并保持热电偶结，用另一种5毫米直径的木榫。对准热电偶结，使得它伸出的销钉的底部之下10-20毫米。对准销钉的相对侧上的铜和康铜导线和12.5毫米宽的聚四氟乙烯（PTFE）管道工的胶带紧紧包住牢固就位持有这些导线。 </li><li>孔另一孔大于5毫米，直径在杜瓦顶部的软木塞，以容纳该第二定位销，并允许样品环附近的热电偶结的垂直高度调节略小。 </li><li>孔在软木塞的第三小孔在杜瓦的顶部以用作氮气汽化通气孔。 </li></ol><p类="jove_title"&gt; 4。在光学杜瓦温度依赖性低温光谱<ol><li>打开在CCD摄谱仪至少1小时的所有电子提前，以允许电子预热和珀耳帖冷却的CCD照相机以达到稳定的工作温度。 </li><li>预热期结束后，波长校准与已知的原子发射线或带一系列的CCD光谱仪。测量的低压原子发射灯发射已知的波长，并通过与已知的频带的波长频带活化相关成分的CCD的像素数的频带的频谱。 注意:在最现代的CCD摄谱仪，包括在此研究中使用的安道尔CCD摄谱仪，波长校准过程在软件自动化。 <ol><li>强度的测定石英卤素灯的3,200ķ操作的灯，它接近于3,200ķBLA的已知光谱曲线谱比较校准光谱仪CK的身体。 </li></ol></li><li>预对准激发和发射光学器件，以确保激发光撞击在环和来自样品的发射的光的样品被收集并且在对CCD-摄谱仪的入口狭缝撞击。 注意:这两步机械过程。第一步是在光学的初始粗对准以获得发射的光到所述光谱仪的入射狭缝，使得一个发光信号由CCD检测到。第二步骤包括由激发光束，所述杜瓦，样品本身在循环，和发射收集光学元件的位置的系统的调整的样本的发光信号强度的仔细的优化。 </li><li>一旦光学对准和优化为4.3所述，测量样本的一个77K的液态氮参考发光光谱。对于该光谱，确保了在铜线环路冷冻薄膜样品中，第ermocouple相邻环路，杜瓦，激发光束和发射收集光学装置都在其最终的优化位置和样品是完全覆盖用液氮。 </li><li>设置热电偶的参比端与包裹在聚四氟乙烯带，就像样品交界处的电线木榫。这保护了参比端，并防止不良导线接触。 </li><li>验证该0℃的参考热电偶结点浸渍在水 - 冰雪泥。检查参比端频繁冰的水平。建立参比端的小广口实验室杜瓦，以降低其冰融化的速度。 </li><li>在检查对文学电压77 K时测得的热电偶电压在一个T型铜 - 康铜热电偶上市77K的。这两个热电偶电压应该是非常接近达成协议。进行适当的修正压力（ 例如 ，使用克劳修斯-克拉珀龙EQUA灰）如果大气压力小于1个大气压。 </li><li>允许液体氮慢慢蒸发掉。 注:样品的温度缓慢上升（历时几个小时）作为样品和液氮水平液氮沸水的结果缓慢增加之间的距离h。该数字电压表来响应该温度上升，从而提供精确的温度测量，因为样品热电偶结完全浸入冷的氮蒸气。 </li><li>暂时打开或解除激励光并用CCD的光谱仪使用制造商的协议来获得的发射光谱。光谱数据采集过程中应优化，只需要几秒钟。 <ol><li>关闭或重新块激发光只是只要数据采集过程完成以最小化不想要的激发光诱导样本光化学和/或激发光产生的错误诱导样品加热。 </li><li>记录在光谱数据采集间隔的开始和结束的热电偶电压。热电偶电压不应该明显地（内0.0-0.1ķ 即相关联的温度变化ΔT），在其上的光谱数据是在给定温度下获得的非常短的时间间隔（〜1-10秒）期间改变。通过引用一个T型铜 - 康铜温度与电压表转换电压读数的温度。 </li></ol></li><li>让液氮汽化以继续，测量另一个频谱当样品温度提高了约5 K.使这些温度依赖性光谱测量过程中在光学，电子或激发光强度没有变化。 注:根据光学杜瓦的质量，这个热身过程需要5到每〜5K的时间间隔15分钟。 </li><li>强度，正确的CCD光谱数据集减去关闭暗帧的强度（ 即 ，由当入口狭缝被阻塞在CCD记录的光谱强度），占波长相关的光谱响应。减去每个样品谱基线暗计数强度计数的水平。 <ol><li>正确用于通过测量已知强度，诸如3200 K的钨卤标准灯的标准的强度，并且使用公知的强度比来测量的强度的波长依赖性的光谱响应以校正样品的测定强度在每个波长。 </li></ol></li></ol>

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The authors have nothing to disclose.

低温冷光光谱该设备的发展产生了必然的。它是含有感兴趣的发色团，并与氧气过饱和溶液可以加载，冷冻，并定位成用于光谱所有在其中样品温度定义良好，稳定，缓慢多变杜瓦/低温恒温器设计，可以是至关重要的。几乎所有的商业低温恒温器需要更多的时间与样品装入比这些实验的限制将使。同样重要的是有一个小型便携式杜瓦/低温恒温器，让轻便装样/在楼上的化学实验室其次是运输楼下光谱实验室冻结。该技术可以应用到需要的量可变低温发光测量实际上任何系统。而所描述的技术中为样品溶液是在室温液体，它也可以扩展到那些固体样品在室温。固体样品可以附着到样品环路通过或者通过胶或机械装置。 有三个优点通过让自然沸水中杜瓦的液氮来获得/低温恒温器慢慢改变样品的温度:（1）样品的热​​平衡是保持整个温度范围内的权益; （二）对光谱数据采集过程，只需要几秒钟，样品温度几乎不变;和（c）在极短的发光的数据采集时间（以及因此的极短的时间将样品需要被激发）最小化招致不必要的激发光诱导样本光化学和/或样品加热的机会。 样品装载前，数字电压表，必须通过在0℃下将两样品和参考热电偶结= 273.15ķ水/冰浴，或者，在77K的液态氮被归零。对于定量升uminescence强度测量中，激发源（激光或弧光灯）必须很好温热并在输出稳定。珀尔帖的CCD冷却器也必须事先测量（至少1-2小时）以及导通，以确保在CCD检测器的稳定运行。为精确的温度测量，必须小心以定位样品环和在正好在杜瓦液氮水平上述相同的高度h热电偶样品交界处。实验是通过用样品的电平以上的液氮水平开始进行。没有更多的液氮在实验过程中加入到杜瓦。在所描述的装置中，液态氮被保持在大气压力。 1K /分钟 - 后液氮水平下降到低于该样品的水平，将样品在≈0.5的速率升温。 3秒在≈5K的时间间隔 - 光谱在1收购。在加热速度小的改动是由实验室诱导的变化湿度和温度。 以确保杜瓦，样品，并在整个实验热电偶的刚性安装是很重要的，因为最轻微的运动将引起不期望的测量的发光强度或温度的变化。杜瓦安装成XYZ定位可具有可调节的光学表要素来进行。用于高精密的工作，所述杜瓦可以安装在一个xyz的光学阶段和样品可以安装在杜瓦一个测角器。关于高湿天，护理也必须考虑，以确保所述光学杜瓦的光学访问的区域不被冷凝的薄膜，因为这遮蔽将减小所测得的发光强度随时间。这个问题可以通过在杜瓦的光学透明区域分配干燥，氮气的一小流予以纠正。 可以说，作为描述的杜瓦/低温恒温器的设计可以被批评为不放置在与在循环中的样本直接物理接触低温热电偶结。直接接触热电偶设计目前正在开发中。然而，定位热电偶结和样品环在杜瓦液氮水平以上相同的高度/在非常靠近低温恒温器被设计成保持易于样品加载的同时履行的热力学条件精确的温度测量的零定律:样品在温度T是与在温度T，其与热电偶结也在温度T热平衡氮蒸气热平衡。监视激光/弧光灯激发强度在整个实验，而不是假设恒定的强度也将是在协议所希望的改进。同样，CCD检测器的灵敏度可以在整个实验进行检查相对于已知恒定强度的标准灯。

在极低温领域，发光分子的电子荧光光谱和荧光寿命的温度依赖性研究提供了丰富的关于从这些国家产生的这些分子的电子激发态和光化学和光物理现象的信息。克罗斯的开拓性随温度变化的光物理调查和同事在钌（II），铑（I），和铑（III）1,10-菲咯啉的配合物，2,2&#39;-联吡啶，和其它配体示出良好的随温度变化的光谱的内在动力阐明发射电子激发态的歧管的结构，对称性，能量学和化学的行为。1-6 然而，要做到随温度变化的低温光谱以及是不是一件小事。这是太容易根据光谱审讯样品不被热EQU<html> ilibrated从而跨越热梯度表现一个宽的温度范围。所得测量光谱是，实际上，排放在温度范围内的叠加。此外，即使在这个温度范围内的平均温度可能是从放置在或靠近于样品温度探头（ 例如 ，热电偶或电阻温度装置）的读出完全不同的。因此，要做到温度依赖性低温光谱正确地需要建立下试样温度是已知的实验条件下，稳定的，均匀的，并且，在时机成熟时，可调节的。这些条件可以与由CCD摄谱仪的极为有限的装置，激发源，光学杜瓦和热电偶下简单，直接的实验方案（参见图1）工作来实现。 "SRC ="/文件/ ftp_upload / 54267 / 54267fig1.jpg"/&gt; 图1.发光光谱仪设置为低温光谱如在此顶视图中所示的系统包括:（一）CCD探测器，（B）光谱仪，（三）入口狭缝和过滤器，（D）的发光收集光学（E）激光或弧光灯激励源，（F）的激发光，（G）熔融硅光学杜瓦在XYZ翻译安装，（H）热电偶样品交界处，（我）的样品，（J 。）热电偶参考结:0°C = 273.15ķ冰/水浴，（k）的数字电压表。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig1large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 样品和错误平均样品温度不希望的热梯度几乎一定会导致如果一个样本的一侧被放置在与低温"冷手指"表面，而样品的另一侧的物理接触是在真空。最实用的方法，以确保完整的示例是在均一可测量温度T是完全沉浸样品和在温度T低温液体的温度探针（ 例如 ，液态氮或液态氦），或在温度T a低温蒸气（ 例如，冷氮气或冷氦蒸汽）。变温度低温恒温器实现通过平衡与电阻加热冷冻剂流量以达到所需的低温样品温度的恒温样品环境7-9的热交换气体可以使用，以确保样品的温度是均匀的。我们的想法是在与交换气体而这又是在与低温恒温器热平衡热平衡的样品。低温恒温器的设计已经出现，实现在各种温度下的样品的热平衡只是通过调节的液面上方的样品高度h制冷剂在存储杜瓦，10个样本被激发，并通过光纤电缆或透镜系统检测发光。在给定的样品/探针高度h，致冷剂蒸气温度为T（h）和该温度的增加为h的增加（ 即 ，杜瓦在蒸气提供了一个平滑的热梯度的dT / DH&gt; 0）。上述的制冷剂气体实际上变成液体交换气体。为H定位一个小样本和温度探头确保在T（h）上的样品的热平衡。以提高样品温度，h的增加。为了降低样品的温度，h的降低。这样的低温恒温器的温度下限为H = 0的液体冷冻剂的温度。此温度下限还可以通过降低压力可以降低。在一个大的存储杜瓦（ 例如 ，一个100升液氦杜瓦或10升液氮杜瓦），冷却剂蒸发RA德是一系列光谱测量由此允许在样品高度h的液态制冷剂上方的调整成为样品温度的已知的调整的时间帧期间可以忽略不计。 在这个实验室从过渡金属配合物的发光的氧诱导淬火的温度依赖性的光谱研究导致了小的熔融二氧化硅的自适应光学杜瓦用于与在77-300 K范围之外液氮变温分光调查（见图2）。 <img alt="图2" fo:display-align="middle" src="/files/ftp_upload/54267/54267fig2.jpg" /> 图2.熔融石英光纤杜瓦设置为变温（77-300 K）低温发光光谱，光杜瓦下图说明了完整的变温系统。 （一）。液氮，（二）TRansparent（4.0厘米）杜瓦，（C）铜样品环，（四）热电偶结，（E）镀银杜瓦地区unsilvered光纤接入区，（F）鳄鱼夹，（G）木榫， （H）距离液氮水平和样品之间，（我）内部和外部杜瓦壁之间抽真空区，（J）软木塞，（K）氮气排气孔（L。）热电偶丝，（M 。）热电偶导线分开并固定带PTFE密封带木榫。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig2large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 熔融二氧化硅是不发光，并提供高的光传输从近紫外，透过可见光，并输出到近红外（〜200-2,000纳米）。此前10，其中液态制冷剂上面的示例高度决定样品温度描述的大型存储系统杜瓦手术的基本概念，成功地延续上小规模使用这种小型光学杜瓦。然而，代替机械调整上述静止液体冷冻剂水平高度的样品高度h来调节样品温度T，相对于该杜瓦本身样本位置是固定的（ 图2）。缓慢沸水在光学杜瓦液氮的历时几个小时逐渐增加下落的液体氮水平（ 图3）以上的样品的距离h。 <img alt="图3" fo:display-align="middle" src="/files/ftp_upload/54267/54267fig3.jpg" /> 图3. 关闭了光学杜瓦的样本区域 。温度:样品浸入液氮中以高度h 0，得到-T 0 = 77 k;样品浸在冷氮蒸气的水平H 1 &lt;H 2 &lt;H 3 &lt;/ SUB&gt;液氮水平之上给予样品温度牛逼1 &lt;T 2 &lt;T 3。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 这允许在样品温度随时间（长达数小时）缓慢的，受控的增加，同时保持两个样品和温度探头，一铜 - 康铜热电偶结，在与冷的氮蒸气的热平衡。发光光谱跨越可见光和近红外区域中每光谱只有几毫秒（或每秒几百谱）用CCD配备发光光谱其间样品温度几乎是恒定（ΔT&lt;0.1 K）的每个光谱获取数据集收购。在温度〜5K的光谱之间的典型等待时间间隔是〜5-15分钟。 Moreo版本，样品加热或通过激发光的样品的光化学降解的影响被最小化，因为激发光仅被允许撞击样品每光谱几秒钟。在简单性，可移植性和样品加载速度的利益，光纤电缆未使用。样品直接与无论是从一个汞弧灯的365nm的频带或405纳米线的二极管激光器的激发。从样品中发出的光从在杜瓦发光样品通过聚光透镜由聚焦透镜拾取直接撞击在摄谱仪的入口狭缝。被调查的钌，铑配合物的样品中氧饱和溶液光谱研究〜10 -3 -10 -4 M溶质的薄膜制成。的解决方案是由在小铜导线环的表面张力保持（〜在形成3毫米环直径选自0.0150。直径的铜线）。然后，热电偶接头高度adjusteð所以它等于样品高度（h 热电偶 = H 样品 ），并在靠近试样回路， 如图2和3。温度通过测量热电偶样品结并用高阻抗数字电压表和比较的温度下对电压表为一个T型铜/康铜热电偶0℃的水/冰热电偶参考结之间的电压差来确定。在导线环捕获的薄膜样品溶液是闪光灯在光学杜瓦液氮通过快速浸入冷冻。然后将冷冻的解决方案允许随时间非常缓慢升温，其余冻结，而其发光光谱是作为温度的函数测量的。发光强度与温度数据根据以下模型进行分析。 在温度的样品的总发光强度&lt;青霉&gt; T被给定为从氧化和unoxygenated络合物所引起的强度之和: <img alt="公式（2）" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq2.jpg" /> 。 （1） 从配合物没有氧气的发光强度假定为与温度无关。然而，氧化配合物的发光强度会随着温度的升高，由于氧气淬指数递减。这可以通过以下形式的Arrhenius方程来描述<img alt="公式3" fo:vertical-align="middle" src="/files/ftp_upload/54267/54267eq3.jpg" /> 。 （2） 在等式（2）中，E a是淬火活化能，k是玻尔兹曼常数。最大发光强度将在低温区观察到（参见图5），其中t<html>这里是热能不足以克服淬火活化屏障（ 即，从复合物到氧气能量转移）。如果式（2）代入公式（1），则表达式<img alt="公式5" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq5.jpg" /> （3） 被获得。在等式（3）， <img alt="公式6" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq6.jpg" />是从在低温区域的氧化复合物所引起的强度。方程的重排（3）收益率<img alt="公式7" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq7.jpg" /> 。 （4） 取方程的两边的自然对数（4）给出的表达7eq8.jpg"/&gt;。（5） 从等式（5）可以明显看出的图<img alt="公式9" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq9.jpg" />与<img alt="10式" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq10.jpg" />会给用直线<img alt="11式" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq11.jpg" /> ，从该发光猝灭活化能得到<img alt="12式" fo:display-align="middle" src="/files/ftp_upload/54267/54267eq12.jpg" /> 。 （6）

<table border="0" cellpadding="0" cellspacing="0" width="819">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Diode laser 405 nm</td>
			<td style="width:189px;">Generic</td>
			<td style="width:119px;"></td>
			<td style="width:295px;">Generic pencil-type laser pointer for luminescence excitation: 5 mW at 405 nm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Quartz optical dewar</td>
			<td style="width:189px;">Custom fabrication</td>
			<td style="width:119px;"></td>
			<td>3.5 cm id. X 25.0 cm length with 4.5 cm unsilvered region for optical access</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Programmable 5 1/2 digit DMM</td>
			<td style="width:189px;">Keithley</td>
			<td style="width:119px;">Model 192</td>
			<td>High impedence DMM for reading thermocouple voltages</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Copper thermocouple wire</td>
			<td style="width:189px;">Omega Engineering</td>
			<td style="width:119px;">SPCP-010</td>
			<td>0.010 in. diameter bare copper thermocouple wire</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Constantan thermocouple wire</td>
			<td style="width:189px;">Omega Engineering</td>
			<td style="width:119px;">SPCC-010</td>
			<td>0.010 in. diameter bare Constantan (copper/nickel) thermocouple wire</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Polychromator/Spectrograph</td>
			<td style="width:189px;">Jarrell-Ash</td>
			<td style="width:119px;">82-415</td>
			<td>0.25 m Ebert monochromator with back slit assembly removed to enable operation as a polychromator</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">CCD camera</td>
			<td style="width:189px;">Andor</td>
			<td style="width:119px;">DV-401-UV</td>
			<td>Thermoelectrically cooled (-35 C) CCD camera for detecting emitted light</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Copper wire for sample loop</td>
			<td style="width:189px;">Generic</td>
			<td style="width:119px;"></td>
			<td>0.0150 in. diameter bare copper wire for sample loop</td>
		</tr>
	</tbody>
</table>

a simple dewar/cryostat for thermally equilibrating samples at known temperatures for accurate cryogenic luminescence measurements

根据一个小的熔融二氧化硅光学杜瓦，热电偶组件的简单液氮杜瓦/低温恒温器装置，以及一个CCD摄谱仪的设计和操作进行说明。指此杜瓦/低温恒温器被设计的实验需要快速样品装载，快速采样冷冻，样品的快速对准，准确和稳定的样品的温度，和小尺寸和杜瓦/低温恒温器低温单元的便携性。当与CCD摄谱仪的快速数据采集率耦合，这杜瓦/低温恒温器是能够在一系列在77-300 K范围之外已知的，稳定的温度下的支撑上的发光样品低温发光光谱测量。发光在铑（Ⅲ）的过渡金属配合物中的氧淬灭的温度依赖性研究是作为调查可能与该杜瓦/低温恒温器的类型的一个例子。在该装置的情况下，用于低温spectros稳定的温度拷贝意味着热与任一液态氮或气态氮在已知可测量温度是由CCD的分光测定的短时间尺度（〜1-10秒）期间不发生变化（ΔT&lt;0.1 K）的平衡的发光试料。杜瓦/低温恒温器的工作原理是取正的热梯度的dT / DH以上在杜瓦其中h是液氮水平以上的样品的高度液氮水平的发展的优点。在几个小时中h的缓慢增加，在样品温度T超过这个时间期间随之缓慢增加液氮结果的缓慢蒸发。一个迅速获得的发射光谱有效地捕获在一个恒定的，热平衡温度样品。

在上述装置中的发光化合物三 （4,7-二甲基-1,10-菲咯啉） ​​合铑的77-200数区域依赖于温度的发光猝灭研究中获得的代表性结果（III）的[Rh（4- ，7-我2 -1,10-phen）的3] 3+，溶解在氧饱和的甘油在表1中列出并在图4,5和 7作图。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 温度（K） </td><td> 倒数温度（1 / K）的 </td><td><img alt="15式" src="/files/ftp_upload/54267/54267eq15.jpg" /></td></tr><tr><td> 163.02 </td><td> 0.006134 </td><td> -4.491 </td></tr><tr><td> 171.69 </td><td> 0.005824 </td><td> -3.216 </td></tr><tr><td> 177.30 </td><td> 0.005640 </td><td> -2.529 </td></tr><tr><td> 183.46 </td><td> 0.005451 </td><td> -1.922 </td></tr><tr><td> 187.15 </td><td> 0.005343 </td><td> -1.421 </td></tr><tr><td> 190.80 </td><td> 0.005241 </td><td> -1.056 </td></tr><tr><td> 194.39 </td><td> 0.005144 </td><td> -0.663 </td></tr><tr><td> 197.94 </td><td> 0.005052 </td><td> -0.394 </td></tr></tbody></table> 表1.淬火的程度与相互开尔文温度为[铑（4,7-ME 2 -1,10-phen）的 3] 3+冷冻甘油玻璃。 <img alt="图4" src="/files/ftp_upload/54267/54267fig4.jpg" /> 图4. 复杂的[Rh的发光光谱（4,7-ME 2 -1,10-phen）的&lt;/ STRONG&gt; 3] 3+温度的函数。（一）栗色= 118 K，（B）的绿色= 171 K，（C）紫色= 185 K，（四）绿松石= 194 K，（即）橙色= 198 K，（F）=灰203 K，（G）棕色= 227 K，（H）蓝色= 234 K. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图5" src="/files/ftp_upload/54267/54267fig5.jpg" /> 图5.峰值发光强度与温度的的[Rh（4,7-二我2 -1,10-phen）的 3] 3+的活化能计算分析。发光数据子集的红色装箱。 一个功能 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig5large.jpg" target="_blank">PL</a>轻松点击此处查看该图的放大版本。 这种复杂的结构示于图6。 <img alt="图6" src="/files/ftp_upload/54267/54267fig6.jpg" /> 图6.发光 Ť 里斯 （4,7-二甲基-1,10-菲咯啉） ​​合铑 的分子结构 （Ⅲ）配合物，的[Rh（4,7-二我 2 -1,10-phen）的 3] 3+。 Me =甲基，啉=邻菲罗啉，数字指的是对菲罗啉环（如图线段）甲基取代的位置。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 表1和图4和图 5所示，发光强度基本上恒定从77 K至175ķ保持，然后逐渐减小从175 K至240 K.温度升高从等式（5），积<img alt="13式" src="/files/ftp_upload/54267/54267eq13.jpg" /> ，一个参数表示淬火的程度，与倒数开尔文温度（1 / T）得到一条直线（R 2 = 0.9988），从31.5千焦/摩尔的氧气发光猝灭活化能为这个复杂计算在溶剂甘油（ 见图7）。 <img alt="图7" src="/files/ftp_upload/54267/54267fig7.jpg" /> 阙程度的自然对数 图7. Arrhenius图（R 2 = 0.998）nching与倒数开尔文温度的影响。该发光试料是含氧〜10 -4 M的[Rh（4,7-二我2 -1,10-phen）的3] 3+（铑=铑，Me =甲基，啉=菲咯啉）中，所述溶剂是甘油，并且发光猝灭活化能E&#39; 一从图中计算为31.5千焦/摩尔; = 0.9988。 <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54267/54267fig7large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 在表2 中，E a值对于其他几个相关配合物，通过这种方法所获得，被列出。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 复合 </td><td> EA（千焦/摩尔） </td><td> R 2 </td></tr><tr><td>的[Rh（5,6-我2 -phen）3] 3+ </td><td> 31.20 </td><td> 0.9922 </td></tr><tr><td>的[Rh（4,7-二我2 -phen）3] 3+ </td><td> 31.50 </td><td> 0.9980 </td></tr><tr><td>的[Rh（3,4,7,8-ME 4 -phen）3] 3+ </td><td> 30.60 </td><td> 0.9907 </td></tr><tr><td>的[Ru（2,2&#39;-联吡啶）3] 2+ </td><td> 15.27 </td><td> 0.9955 </td></tr></tbody></table> 表2.荧光猝灭活化能由氧气和 值的Rh（III）和Ru（II）配合物的甘油。 而以最佳的作者的知识没有其他数据可以直接与这些结果进行比较，实验数据，以公式（5），并彼此相关的分子的构象，提供了强有力的内部一致的我国证据Ë该装置和程序生产出可以被成功地分析准确，热平衡的样品温度。这方面的证据，在与在装置直接热校准证据一起服用，表示的同时，将所获得的荧光光谱的样品温度是已知的和恒定整个样品。

Watch this Scientific Journal Video about A Simple Dewar/Cryostat for Thermally Equilibrating Samples at Known Temperatures for Accurate Cryogenic Luminescence Measurements at JoVE.com

A Simple Dewar/Cryostat for Thermally Equilibrating Samples at Known Temperatures for Accurate Cryogenic Luminescence Measurements

A simple liquid nitrogen Dewar/cryostat apparatus comprised of a small fused silica optical Dewar, a thermocouple, and a charge-coupled device (CCD) spectrograph are described. The experiments for which this Dewar/cryostat is designed require fast sample loading, freezing, and alignment, accurate and stable sample temperatures, and small size/portability.

一个简单的杜瓦瓶/低温恒温器的热的样品配平在为准确低温发光测量已知温度

The design and operation of a simple liquid nitrogen Dewar/cryostat apparatus based upon a small fused silica optical Dewar, a thermocouple assembly, and ...

a-simple-dewarcryostat-for-thermally-equilibrating-samples-at-known

Nanyang Technological University

Research

JoVE Journal

Engineering

9.5K 次观看.  Concordia University. A simple liquid nitrogen Dewar/cryostat apparatus comprised of a small fused silica optical Dewar, a thermocouple, and a charge-coupled device (CCD) spectrograph are described. The experiments for which this Dewar/cryostat is designed require fast sample loading, freezing, and alignment, accurate and stable sample temperatures, and small size/portability.

视频: A Simple Dewar/Cryostat for Thermally Equilibrating Samples at Known Temperatures for Accurate Cryogenic Luminescence Measurements

Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (&omega;) and momentum (k) and the probability to find them in a particular state with given &omega; and k is described by the spectral function A(k, &omega;). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample.
In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be determined with an unprecedented clarity.

The overall goal of this method is to determine the low-energy electronic structure of solids at ultra-low temperatures using Angle-Resolved Photoemission Spectroscopy with synchrotron radiation.

在极低的温度下角分辨光电子能谱

The physical properties of a material are defined by its  electronic structure. Electrons in solids are characterized by energy (&omega;)  and momentum ...

科研

工程学

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 ...

Synthesis and Microdiffraction at Extreme Pressures and Temperatures

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary interiors, design materials with novel properties, understand the mechanical behavior of materials exposed to very high stresses as in explosions or impacts. Synthesis and structural analysis of materials at extreme conditions of pressure and temperature entails remarkable technical challenges. In the laser heated diamond anvil cell (LH-DAC), very high pressure is generated between the tips of two opposing diamond anvils forced against each other; focused infrared laser beams, shined through the diamonds, allow to reach very high temperatures on samples absorbing the laser radiation. When the LH-DAC is installed in a synchrotron beamline that provides extremely brilliant x-ray radiation, the structure of materials under extreme conditions can be probed in situ. LH-DAC samples, although very small, can show highly variable grain size, phase and chemical composition. In order to obtain the high resolution structural analysis and the most comprehensive characterization of a sample, we collect diffraction data in 2D grids and combine powder, single crystal and multigrain diffraction techniques. Representative results obtained in the synthesis of a new iron oxide, Fe4O5 1 will be shown.

The laser heated diamond anvil cell combined with synchrotron micro-diffraction techniques allows researchers to explore the nature and properties of new phases of matter at extreme pressure and temperature (PT) conditions. Heterogeneous samples can be characterized in situ under high pressure by 2D mapping and combined powder, single-crystal and multigrain diffraction approaches.

在极端的压力和温度的合成和Microdiffraction

High pressure compounds and polymorphs are investigated for a broad range of purposes such as determine structures and processes of deep planetary ...

Convergent Polishing: A Simple, Rapid, Full Aperture Polishing Process of High Quality Optical Flats &amp; Spheres

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial shape (i.e., surface figure), will converge to final surface figure with excellent surface quality under a fixed, unchanging set of polishing parameters in a single polishing iteration. In contrast, conventional full aperture polishing methods require multiple, often long, iterative cycles involving polishing, metrology and process changes to achieve the desired surface figure. The Convergent Polishing process is based on the concept of workpiece-lap height mismatch resulting in pressure differential that decreases with removal and results in the workpiece converging to the shape of the lap. The successful implementation of the Convergent Polishing process is a result of the combination of a number of technologies to remove all sources of non-uniform spatial material removal (except for workpiece-lap mismatch) for surface figure convergence and to reduce the number of rogue particles in the system for low scratch densities and low roughness. The Convergent Polishing process has been demonstrated for the fabrication of both flats and spheres of various shapes, sizes, and aspect ratios on various glass materials. The practical impact is that high quality optical components can be fabricated more rapidly, more repeatedly, with less metrology, and with less labor, resulting in lower unit costs. In this study, the Convergent Polishing protocol is specifically described for fabricating 26.5 cm square fused silica flats from a fine ground surface to a polished ~&#955;/2 surface figure after polishing 4 hr per surface on a 81 cm diameter polisher.

Convergent Polishing: A Simple, Rapid, Full Aperture Polishing Process of High Quality Optical Flats & Spheres

A novel optical polishing process, called &#8220;Convergent Polishing&#8221;, which enables faster, lower cost polishing, is described. Unlike conventional polishing processes, Convergent Polishing allows a glass workpiece to be polished in a single iteration and with high surface quality to its final surface figure without requiring changes to polishing parameters.

收敛抛光:高品质光学平面与球的一种简单，快速，全口径抛光工艺

Convergent Polishing is a novel polishing system and method for finishing flat and spherical glass optics in which a workpiece, independent of its initial ...

Micro-masonry for 3D Additive Micromanufacturing

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called &#8216;inks&#8217;) from a substrate where they are generated to a different substrate by utilizing elastomeric stamps. Transfer printing enables the integration of heterogeneous materials to fabricate unexampled structures or functional systems that are found in recent advanced devices such as flexible and stretchable solar cells and LED arrays. While transfer printing exhibits unique features in material assembly capability, the use of adhesive layers or the surface modification such as deposition of self-assembled monolayer (SAM) on substrates for enhancing printing processes hinders its wide adaptation in microassembly of microelectromechanical system (MEMS) structures and devices. To overcome this shortcoming, we developed an advanced mode of transfer printing which deterministically assembles individual microscale objects solely through controlling surface contact area without any surface alteration. The absence of an adhesive layer or other modification and the subsequent material bonding processes ensure not only mechanical bonding, but also thermal and electrical connection between assembled materials, which further opens various applications in adaptation in building unusual MEMS devices.

This paper introduces a 3D additive micromanufacturing strategy (termed &#8216;micro-masonry&#8217;) for the flexible fabrication of microelectromechanical system (MEMS) structures and devices. This approach involves transfer printing-based assembly of micro/nanoscale materials in conjunction with rapid thermal annealing-enabled material bonding techniques.

微砌筑的3D添加剂Micromanufacturing

Transfer printing is a method to transfer solid micro/nanoscale materials (herein called &#8216;inks&#8217;) from a substrate where they are generated to ...

Three-dimensional Particle Tracking Velocimetry for Turbulence Applications: Case of a Jet Flow

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic recording of image sequences. The basic components, features, constraints and optimization tips of a 3D-PTV topology consisting of a high-speed camera with a four-view splitter are described and discussed in this article. The technique is applied to the intermediate flow field (5 &#60;x/d &#60;25) of a circular jet at Re &#8776; 7,000. Lagrangian flow features and turbulence quantities in an Eulerian frame are estimated around ten diameters downstream of the jet origin and at various radial distances from the jet core. Lagrangian properties include trajectory, velocity and acceleration of selected particles as well as curvature of the flow path, which are obtained from the Frenet-Serret equation. Estimation of the 3D velocity and turbulence fields around the jet core axis at a cross-plane located at ten diameters downstream of the jet is compared with literature, and the power spectrum of the large-scale streamwise velocity motions is obtained at various radial distances from the jet core.

A three-dimensional particle tracking velocimetry (3D-PTV) system based on a high-speed camera with a four-view splitter is described here. The technique is applied to a jet flow from a circular pipe in the vicinity of ten diameters downstream at Reynolds number Re &#8776; 7,000.

湍流应用三维粒子跟踪测速:一喷流病例

3D-PTV is a quantitative flow measurement technique that aims to track the Lagrangian paths of a set of particles in three dimensions using stereoscopic ...

Nanostructured Ag-zeolite Composites as Luminescence-based Humidity Sensors

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high external quantum efficiencies (EQE) and spans the whole visible spectrum. It has been recently reported that the UV excited luminescence of partially Li-exchanged sodium Linde type A zeolites [LTA(Na)] containing luminescent silver clusters can be controlled by adjusting the water content of the zeolite. These samples showed a dynamic change in their emission color from blue to green and yellow upon an increase of the hydration level of the zeolite, showing the great potential that these materials can have as luminescence-based humidity sensors at the macro and micro scale. Here, we describe the detailed procedure to fabricate a humidity sensor prototype using silver-exchanged zeolite composites. The sensor is produced by suspending the luminescent Ag-zeolites in an aqueous solution of polyethylenimine (PEI) to subsequently deposit a film of the material onto a quartz plate. The coated plate is subjected to several hydration/dehydration cycles to show the functionality of the sensing film.

A protocol for the synthesis of moisture-responsive luminescent Ag-zeolite composites is described in this report.

纳米银沸石复合材料作为基于发光的湿度传感器

Small silver clusters confined inside zeolite matrices have recently emerged as a novel type of highly luminescent materials. Their emission has high ...

Measuring the Densities of Aqueous Glasses at Cryogenic Temperatures

We demonstrate a method for determining the vitreous phase cryogenic temperature densities of aqueous mixtures, and other samples that require rapid cooling, to prepare the desired cryogenic temperature phase. Microliter to picoliter size drops are cooled by projection into a liquid nitrogen-argon (N2-Ar) mixture. The cryogenic temperature phase of the drop is evaluated using a visual assay that correlates with X-ray diffraction measurements. The density of the liquid N2-Ar mixture is adjusted by adding N2 or Ar until the drop becomes neutrally buoyant. The density of this mixture and thus of the drop is determined using a test mass and Archimedes principle. With appropriate care in drop preparation, management of gas above the liquid cryogen mixture to minimize icing, and regular mixing of the cryogenic mixture to prevent density stratification and phase separation, densities accurate to &#60;0.5% of drops as small as 50 pL can readily be determined. Measurements on aqueous cryoprotectant mixtures provide insight into cryoprotectant action, and provide quantitative data to facilitate thermal contraction matching in biological cryopreservation.

A protocol for determining the vitreous phase densities of micro- to pico-liter size drops of aqueous mixtures at cryogenic temperatures is described.

在低温下测量水性玻璃的密度

We demonstrate a method for determining the vitreous phase cryogenic temperature densities of aqueous mixtures, and other samples that require rapid ...

Processing of Bulk Nanocrystalline Metals at the US Army Research Laboratory

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued development of nanocrystalline metals. Despite these efforts, the transition of these materials from the lab bench to actual applications has been blocked by the inability to produce large scale parts that retain the desired nanocrystalline microstructures. Following the development of a method proven to stabilize the nanosized grain structure to temperatures approaching that of the melting point for the given metal, the US Army Research Laboratory (ARL) has progressed to the next stage in the development of these materials - namely the production of large scale parts suitable for testing and evaluation in a range of relevant test environments. This report provides a broad overview of the ongoing efforts in the processing, characterization, and consolidation of these materials at ARL. In particular, focus is placed on the methodology used for producing the nanocrystalline metal powders, in both small and large-scale amounts, that are at the center of ongoing research efforts.

This paper provides a brief overview of the ongoing efforts at the Army Research Laboratory on the processing of bulk nanocrystalline metals with an emphasis on the methodologies used for the production of the novel metal powders.

美国陆军研究实验室散装纳米晶金属的加工

Given their potential for significant property improvements relative to their large grained counterparts, much work has been devoted to the continued ...

Carrier Lifetime Measurements in Semiconductors through the Microwave Photoconductivity Decay Method

This work presents a protocol employing the microwave photoconductivity decay (&#956;-PCD) for measurement of the carrier lifetime in semiconductor materials, especially SiC. In principle, excess carriers in the semiconductor generated via excitation recombine with time and, subsequently, return to the equilibrium state. The time constant of this recombination is known as the carrier lifetime, an important parameter in semiconductor materials and devices that requires a noncontact and nondestructive measurement ideally achieved by the &#956;-PCD. During irradiation of a sample, a part of the microwave is reflected by the semiconductor sample. Microwave reflectance depends on the sample conductivity, which is attributed to the carriers. Therefore, the time decay of excess carriers can be observed through detection of the reflected microwave intensity, whose decay curve can be analyzed for estimation of the carrier lifetime. Results confirm the suitability of the &#956;-PCD protocol in measuring the carrier lifetime in semiconductor materials and devices.

As one of the important physical parameters in semiconductors, carrier lifetime is measured herein via a protocol employing the microwave photoconductivity decay method.

微波导光衰减法测量半导体中的载波寿命

This work presents a protocol employing the microwave photoconductivity decay (&#956;-PCD) for measurement of the carrier lifetime in semiconductor ...