Name: the effect of ultraviolet radiation on the chemical bath deposition of bis(thiourea) cadmium chloride crystals and the subsequent cds obtention
Uploaded: 2018-08-30T14:00:00.000+00:00
Duration: 5 min 21 s
Description: Watch this Scientific Journal Video about The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bisthiourea Cadmium Chloride Crystals and the Subsequent CdS Obtention at JoVE.com

L.E. 和琼斯 Willars 罗德里格斯感谢 CONACYT 的奖学金。E.A. 查韦斯-Urbiola 感谢 CONACYT 为 "Catedras CONACYT" 计划。作者还承认阿维拉的技术援助, Landaverde, J.E. 乌尔维纳 Alvárez, Jiménez 涅托。

注意: 本议定书中使用的化学品具有毒性和致癌性;因此, 必须认真遵守安全建议和程序。佩戴适当的防护设备, 查阅相关材料安全数据表 (MSDS)。
1. 二 (硫脲) 氯化镉的合成
<ol><li>
前体溶液的制备
	<ol>
<li>将500毫升去离子水倒入1升烧杯中, 持续搅拌;添加0.3 毫升盐酸在36.5% 浓度, 确保溶液的 pH 值尽可能接近 3, 使用 ph 计。 注意: 为了避免任何健康影响, 强烈建议在通风罩内执行此操作。</li>
		<li>倒入50毫升的前体溶液, 如步骤1.1.1 中所示, 进入两个100毫升烧杯 (以下, 这些烧杯将被命名为 A 和 B)。 注: 两个实验 (A 和 B, 依赖于烧杯使用) 同时进行。只有实验 B 才会暴露在紫外线照射下。</li>
	</ol>
</li>
	<li>每个烧杯 (A 和 B) 的重量为2.29 克 CdCl2 。 警告: 在通风罩内执行此操作, 因为所使用的材料被认定为危险的。镉具有剧毒, 在吸入时被认定为致癌物质;必须小心处理。</li>
	<li>对每个烧杯 (A 和 B) 的1.33 克 CS (NH2)2进行称量。 注意: 在通风罩内执行此操作, 因为使用的材料危险不健康。硫脲在吸入时具有剧毒, 必须小心处理。</li>
	<li>将2.29 克 CdCl2和1.33 克的 CS (NH2)2添加到包含前体溶液50毫升的每个烧杯 (A 和 B) 中。</li>
</ol>2. 双 (硫脲) 氯化镉的比较合成
<ol><li>
无紫外线光的实验安排 (A)。
	<ol>
<li>将烧杯 (A) 放在搅拌热板上, 加热至 343 k, 将其设置为适度搅拌速度。 注意: 在通风罩内执行此操作。</li>
		<li>保持溶液在烧杯 (A) 适度搅拌2小时的板材在 343 K。</li>
	</ol>
</li>
	<li>
实验安排与紫外光 (B)。
	<ol>
<li>把烧杯 B 放在盘子上, 加热到 343 k. 在适度水平上设置搅拌速度, 并在 UV 光源上切换。 注意: 实验安排如图 1所示。 注意: 在通风罩内执行此操作。</li>
		<li>保持步骤2.2.1 中所述的温度和搅拌条件为2小时。</li>
	</ol>
</li>
</ol>3. 获得双 (硫脲) 氯化镉晶体
<ol><li>装载2玻璃漏斗与过滤器纸 (40, Ø = 125 毫米), 每一个在100毫升容量瓶, a 和 B。在现阶段避免晶体形成;在过滤之前不要让溶液冷却。</li>
	<li>过滤解决方案 A 和 B 通过纸, 每个到自己的100毫升烧瓶。 注意: 在通风罩内执行此操作。</li>
	<li>让两个溶液内的容积烧瓶冷却到室温。 注: 晶体开始生长在第一分钟内的容积烧瓶。</li>
	<li>用新的过滤纸再次准备过滤组件 (步骤 3.1)。</li>
	<li>通过过滤纸将溶液与晶体过滤成单独的容积烧瓶。 注意: 在通风罩内执行此操作。</li>
	<li>将滤纸上的晶体转移到相应的手表玻璃上。 注: 在这一点上, 有2手表眼镜, 1 为 A 和1的 B。</li>
	<li>通过粉末 X 射线衍射 (XRD) 和拉曼光谱的研究, 证实了双 (硫脲) 氯化镉晶体的存在. 12。</li>
</ol>4. 煅烧晶体以获得 CdS
<ol><li>将步骤3.7 中获得的晶体放置到2不同的坩埚中, 1 用于 A 和1为 B。</li>
	<li>预热电热实验炉, 并将其温度稳定在 773 K 或更高。</li>
	<li>将步骤4.1 的坩埚放入预热炉内。 注意: 煅烧过程中释放的蒸气是有毒的。确保炉子是在通风罩, 因为有毒的烟雾, 它将被耗尽。</li>
	<li>让材料站在炉内1小时在 773 K。然后, 关掉炉子, 让它冷却到室温。然后, 从烤箱中取出坩埚。</li>
</ol>

<ol>
	<li>Venkataramanan, V., Maheswaran, S., Sherwood, J. N., Bhat, H. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Crystal+growth+and+physical+characterization+of+the+semiorganic+bis(thiourea)+cadmium+chloride.">Crystal growth and physical characterization of the semiorganic bis(thiourea) cadmium chloride.</a> Journal of Crystal Growth. 179 (3-4), 605-610 (1997).</li><li>Ushasree, P. M., Muralidharan, R., Jayavel, R., Ramasamy, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+of+bis(thiourea)+cadmium+chloride+single+crystals+a+potential+NLO+material+of+organometallic+complex.">Growth of bis(thiourea) cadmium chloride single crystals a potential NLO material of organometallic complex.</a> Journal of Crystal Growth. 218 (2-4), 365-371 (2000).</li><li>Ushasree, P. M., Jayavel, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+and+micromorphology+of+as-grown+and+etched+bis(thiourea)+cadmium+chloride+(BTCC)+single+crystals.">Growth and micromorphology of as-grown and etched bis(thiourea) cadmium chloride (BTCC) single crystals.</a> Optical Materials. 21 (1-3), 569-604 (2002).</li><li>Pawar, S. M., Pawar, B. S., Kim, J. H., Joo, O., Lokhande, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+status+of+chemical+bath+deposited+metal+chalcogenide+and+metal+oxide+thin+films.">Recent status of chemical bath deposited metal chalcogenide and metal oxide thin films.</a> Current Applied Physics. 11 (2), 117-161 (2011).</li><li>Suriakarthick, R., Kumar, V. N., Shyju, T. S., Gopalakrishnan, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Investigation+on+post+annealed+copper+sulfide+thin+films+from+photochemical+deposition+technique.">Investigation on post annealed copper sulfide thin films from photochemical deposition technique.</a> Materials Science in Semiconductor Processing. 26 (1), 155-161 (2014).</li><li>Podder, J., Kobayashi, R., Ichimura, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photochemical+deposition+of+Cu+x+S+thin+films+from+aqueous+solutions.">Photochemical deposition of Cu x S thin films from aqueous solutions.</a> Thin Solid Films. 472 (1-2), 71-75 (2005).</li><li>Gunasekaran, M., Gopalakrishnan, R., Ramasamy, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deposition+of+ZnS+thin+films+by+photochemical+deposition+technique.">Deposition of ZnS thin films by photochemical deposition technique.</a> Materials Letters. 58 (1-2), 67-70 (2004).</li><li>Ichimura, M., Goto, F., Ono, Y., Arai, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Deposition+of+CdS+and+ZnS+from+aqueous+solutions+by+a+new+photochemical+technique.">Deposition of CdS and ZnS from aqueous solutions by a new photochemical technique.</a> Journal of Crystal Growth. 198 (1), 308-312 (1999).</li><li>Kumaresan, R., Ichimura, M., Sato, N., Ramasamy, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+novel+photochemical+deposition+technique+for+the+deposition+of+indium+sulfide.">Application of novel photochemical deposition technique for the deposition of indium sulfide.</a> Materials Science Engineering: B. 96 (1), 37-42 (2002).</li><li>Rama, G., Jeevanandam, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evolution+of+different+morphologies+of+CdS+nanoparticles+by+thermal+decomposition+of+bis(thiourea)cadmium+chloride+in+various+solvents.">Evolution of different morphologies of CdS nanoparticles by thermal decomposition of bis(thiourea)cadmium chloride in various solvents.</a> Journal of Nanoparticle Research. 17 (1), 1-13 (2015).</li><li>Pabitha, G., Dhanasekaran, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Growth+and+characterization+of+a+nonlinear+optical+crystal+-+bis+thiourea+cadmium+chloride.">Growth and characterization of a nonlinear optical crystal - bis thiourea cadmium chloride.</a> International Journal of Innovative Research in Science, Engineering and Technology. 4 (1), 34-38 (2015).</li><li>Trujillo, L. E., 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=Di-thiourea+cadmium+chloride+crystals+synthesis+under+UV+radiation+influence.">Di-thiourea cadmium chloride crystals synthesis under UV radiation influence.</a> Journal of Crystal Growth. 478 (1), 140-145 (2017).</li><li>Elilarassi, R., Maheshwari, S., Chandrasekaran, G. <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+optical+characterization+of+CdS+nanoparticles+synthesized+using+a+simple+chemical+reaction+route.">Structural and optical characterization of CdS nanoparticles synthesized using a simple chemical reaction route.</a> Optoelectronics and Advanced Materials - Rapid Communications. 4 (3), 309-312 (2010).</li><li>Selvasekarapandian, S., Vivekanandan, K., Kolandaivel, P., Gundurao, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vibrational+Studies+of+Bis(thiourea)+Cadmium+Chloride+and+Tris(thiourea)+Zinc+Sulphate+Semiorganic+Non-linear+Optical+Crystals.">Vibrational Studies of Bis(thiourea) Cadmium Chloride and Tris(thiourea) Zinc Sulphate Semiorganic Non-linear Optical Crystals.</a> Crystal Research &amp; Technology. 32 (2), 299-309 (1997).</li></ol>

作者没有什么可透露的。

本节中提出的讨论只侧重于议定书, 而不是着重于代表结果中已经显示的结果。
该议定书最关键的部分之一是编写前体解决方案。保持酸性 pH 值以避免 Cd (OH)2的形成是至关重要的。如果 pH 不是酸性的, 它导致 CdS 的直接形成由于硫脲离解和 cd (OH)2形成。 第二个最重要的步骤是步骤 3.2, 过滤解决方案之前必须执行的解决方案冷却下来, 因为否则, 冷却导致晶体的形成开始。
在本协议中, 报告了 CdCl2-[CS2)2] 2的快速增长, 这是在不到10分钟的时间内发生的。其他研究人员 (见 Ushasree等.2、3) 报告单晶的生长时间长达45天。
由于反应的控制相对较低, 不可能产生单晶。相比之下, 当使用 UV 光时, 这种技术会诱发晶体中的几个缺陷。由于 UV 光会导致晶体中的缺陷, 任何可能需要缺陷的应用都可能是一个潜在的应用。未来的研究可能包括使用不同光源控制晶体中的缺陷。另外, 为了进行兴奋剂, 使用 CdCl2-[CS (NH2)2]2与不同的半导体, 这些缺陷可能是有用的最终纳入纳米粒子或量子点的 CdS。
CdCl2-[CS2)2]2的合成方法在执行反应时使用紫外光 (PCBD) 在本协议中首次以广泛而详细的方式报告。

一个重要的研究领域是单一晶体;他们的成长是针对不同的应用。这些材料可作为用于激光技术领域、光电子领域和信息1的非线性光学资料, 为他们的调查提供了一个机会。二 (硫脲) 氯化镉是一种金属有机材料, 可从两个前体、硫脲和氯化镉中合成, 遵循以下化学公式: 2 cs (nh2)2 + CdCl2 CdCl2-[cs2)2]2. 这种金属-有机材料是在不同的反应条件下制备的, 如温度和 pH 值, 但在紫外线 (UV) 光的帮助下从来没有。
报告了 pH 值对晶体结构的影响;在 pH < 6, 有可能获得单晶的形成。这些反过来, 根据 pH 值的范围进行修改。在6到4的间隔时间内, 可以获得六角结构, 因为如果 pH 值为 < 4, 正交晶体结构得到2。离子离解由酸性 pH 值 Cd2 +和 Cl 促进, 因为它防止氢氧化镉形成 [Cd (OH)2]。这稳定了镉: 一个镉原子加入两个无硫自由基和两个氯。
在这里, 采用化学浴沉积技术 (CBD) 进行合成, 控制化学反应时干预的不同条件3。在 CBD 中, 控制化学反应的因素有: 溶液温度、前驱离子、溶液 pH 值、试剂数量和搅拌速度等。另一方面, 这里使用的比较技术称为光化学浴沉积 (PCBD), 因为它使用 UV 光的帮助。有报道称, 紫外线光协助已被用于合成x4、5、ZnS6、CdS7和 InS8等薄膜。市村和 Gunasekaran9目前在他们的工作, 硫酸盐溶液有一个吸收边缘接近 300 nm。由于这种吸收范围, 紫外线辐射的应用, 这导致了类似的排放范围, 与吸收的解决方案。
二 (硫脲) 氯化镉的另一种性质是加热时降解。它在 512 K 和以上的温度下进行初始分解, 形成硫化镉 (CdS)。降解反应如下: [Cd (CS2]2] Cl2 →Δ CdS + HNCS + nh3 + nh4SCN。这种降解产生 thiocyanuric 酸和各种 thiocyanates10,11。此外, 研究组还对紫外线辐射引起的一些影响进行了研究12。最后, 本文介绍了双 (硫脲) 氯化镉晶体的比较合成方法, 以及紫外光的影响。

<table><tbody><tr><td>&lt;strong&gt;Reagents&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Cadmium chloride Anh. ACS, 99.4 %</td><td>Fermont</td><td>PQ24291</td><td>Highly toxic</td></tr><tr><td>Thiourea technical grade, 99.9 %</td><td>Reasol</td><td>R5913</td><td>Toxic</td></tr><tr><td>Hydrochloric acid, 36.5 &amp;ndash; 38.0 %</td><td>J.T.Baker</td><td>MFCD00011324</td><td>Highly corrosive liquid</td></tr><tr><td>&lt;strong&gt;Material&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Filter paper</td><td>Whatman</td><td>1440 125</td><td>40, Ashless, Circles, 125 mm</td></tr><tr><td>Beaker</td><td>Kimax</td><td>1400</td><td>100 mL</td></tr><tr><td>Volumetric Flask</td><td>Kimax</td><td>28012-100</td><td>Class A 100 mL</td></tr><tr><td>Glass Funnel</td><td>Kimax</td><td>28980-150</td><td>Addition Funnel, Long Stem, 60&amp;deg; Angle, Wide Top. Type I, Class B.</td></tr><tr><td>Watch glasses</td><td>Pyrex</td><td>9985-150</td><td>Corning, 150&amp;nbsp;mm</td></tr><tr><td>Crucibles</td><td>Fisherbrand</td><td>FB-965-D</td><td>High-Form Porcelain</td></tr><tr><td>&lt;strong&gt;Equipment&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Furnace</td><td>Briteg Instrumentos Cientificos S.A. de C.V.</td><td>1010</td><td></td></tr><tr><td>Fume Hood</td><td>Fisher Alders, S.A. de C.V.</td><td>F1124</td><td></td></tr><tr><td>Light surce</td><td>Philips</td><td>PL-S 9W UV-A/2P 1CT/6X 10 CC</td><td></td></tr><tr><td>pH meter</td><td>OAKTON</td><td>WD-35419-10</td><td></td></tr><tr><td>Hotplate whit magnetic stirrer</td><td>Cole-Parmer</td><td>JZ-04660-75</td><td></td></tr></tbody></table>

the effect of ultraviolet radiation on the chemical bath deposition of bis(thiourea) cadmium chloride crystals and the subsequent cds obtention

本文比较研究了用化学浴沉积技术对 367 nm 波长的紫外光照射下双 (硫脲) 氯化镉晶体的制备效果。两个实验进行了比较: 一个没有紫外线光和其他的紫外线光的帮助。两个实验都是在同等条件下进行的, 温度为 343 K, pH 值为3.2。所用的前体为氯化镉 (CdCl2) 和硫脲 [CS (NH2)2], 溶解在50毫升的去离子水中, 酸性 pH 值。在该实验中, 在进行化学反应的时刻, 寻求电磁辐射的相互作用。结果表明晶体与紫外光之间存在相互作用;紫外光协助导致晶体生长在针状的形状。此外, 最终的产品是硫化镉, 并显示没有明显的差异, 当合成与或不使用 UV 光。

在两种前驱体溶液中, a 和 B 的紫外-可见光扩散反射吸收光谱显示了双 (硫脲) 氯化镉络合物-CdCl2-(CS2)2)2的存在。这在图 2c中由 250-500 nm 范围内的广泛吸收带证明。反过来,图 2c是独立 CdCl2和 CS (NH2)2在解决方案中的主要吸收带的组合, 如图 2a和2b所示。此外, 600-700 nm 范围内的二次波段在反应物 "(图 2a和2b) 光谱中明显可见, 在复合体的紫外-可见光吸收光谱 (图 2c) 中无法检测到。后者的特征也是决定将图 2c指定为一个例子的复杂 CdCl2-[CS (NH2)2]2的特征谱。
图 3显示了协议步骤3.6 中获得的晶体的拉曼光谱。它显示的峰值对应的 Cd Cl, N-c, 和 c-s 键 (217 厘米-1, 469 厘米-1, 715 厘米-1, 分别), 它同意的结果, 由 s Selvasekarapandian等。14. 另一方面, 下午 Ushasree等。3以前报告说, 光谱的变化是由于在 CdCl2-[CS (NH2)2]2的最终结构中保持在一起的 Cl-Cd S 键数较高。当使用 UV 时, 较高的计数会导致拉曼光谱的增大。这是因为两性离子的形成。两性离子是一种电中性化学化合物, 在不同的原子上具有正向和负的正规电荷。Selvasekarapandian,S, 等等.14报告说, 两性离子保持硫脲的稳定性, 并允许对镉离子的约束。虽然图 3展示了相同的债券为两个实验, 对于一个没有紫外线援助 (CBD), 这样的强度较低, 这表明了较小的债券数量。
X 射线衍射 (XRD) 和扫描电镜 (SEM) 的分析, 对上述相同的粉末 (在步骤3.6 的协议) 进行。首先,图 4a显示了 XRD 模式。模式完全索引与数据表 18-1962 CdCl2-[CS (NH2)2]2, 证实了复杂的存在。在使用紫外光时 (020) 和 (001) 平面上的优先增长, 分别对应于结构内的硫和镉原子。其次, 在图 4b和4c的 SEM 图像中观察晶体的形貌, 可以看到紫外光的影响: 当使用 uv 光时, 会形成针状晶体 4x-6x 较大 (图 4c)。第三, 在图 4b中, 得到了典型的晶体, 这些结果与下午 Ushasree 的报告很好地吻合. 2. 随后, 通过热重分析 (TGA) 分析了《议定书》步骤3.6 中获得的晶体, 以确定它们在煅烧前的行为。图 5中所得到的热重分析显示了两种实验的相似行为, 当使用 UV (PCBD) 时, 当它不是 (CBD) 时, 两者都与 v Venkataramanan等所获得的结果很好地一致。1。
然后, 为了获得 CdS, 773 K 的煅烧是在类似条件下的实验中进行的, Ushasree,下午, 等等.报告了3 。接下来, 在图 6a中, 煅烧复合体的 DRX 显示了 CBD与PCBD 所获得的 CdS 中没有代表性的差异。通过 SEM,图 6b和6c展示了 PCBD (图 6c) 比 CBD (图 6b) 的平均粒度稍显突出。因此, 紫外光促进了硫与镉的结合, 这就导致了 CdCl2-[CS2]2]2的晶体结构的优先生长。最后, 煅烧后获得的 CdS 没有明显的差异。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/57682/57682fig1.jpg"> 图 1: 带有 UV 光的实验安排.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57682/57682fig1large.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/57682/57682fig2.jpg"> 图 2: 前体溶液的光学吸收谱.(a) CdCl, (b) CS (nh2)2, (c) CdCl2 + CS (NH2)2。a)、b) 和 c) 显示紫外光的部分吸收。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57682/57682fig2large.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/57682/57682fig3.jpg"> 图 3: 拉曼光谱.双 (硫脲) 氯化镉与 (PCBD) 和无紫外线 (CBD) 的光谱比较。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57682/57682fig3large.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/57682/57682fig4.jpg"> 图 4: XRD.本文介绍了双 (硫脲) 氯化镉和 PCBD 的 XRD 图谱。得到的晶体和 SEM 图像的方案, 没有紫外线辅助在 b) 和与它在 c)。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57682/57682fig4large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/57682/57682fig5.jpg"> 图 5: 热重分析.利用 CBD 和 PCBD 获得的双 (硫脲) 氯化镉晶体的热重比较 (分别实验 A 和 B)。<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57682/57682fig5large.jpg" target="_blank">请单击此处查看此图的较大版本.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/57682/57682fig6.jpg"> 图 6: 获得的 cd.在 a) 显示了 CBD与PCBD 的 XRD 对比。b) 和 c) 展示了在 773 K 煅烧后获得的最终产品的 SEM 图像.<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/57682/57682fig6large.jpg" target="_blank">请单击此处查看此图的较大版本</a>。

Watch this Scientific Journal Video about The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bisthiourea Cadmium Chloride Crystals and the Subsequent CdS Obtention at JoVE.com

The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bisthiourea Cadmium Chloride Crystals and the Subsequent CdS Obtention

本文提出了一种用化学浴沉积法合成双 (硫脲) 镉氯化物晶体的协议。两个实验被描述: 一个由紫外光辅助与没有紫外光的一。

紫外辐射对双 (硫脲) 氯化镉晶体化学镀液沉积的影响及随后的 CdS 获得

In this work, the effects on the preparation of bis(thiourea) cadmium chloride crystals when illuminated with ultraviolet (UV) light at a wavelength of ...

the-effect-ultraviolet-radiation-on-chemical-bath-deposition-bis

Nanyang Technological University

Research

JoVE Journal

Chemistry

The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bis(thiourea) Cadmium Chloride Crystals and the Subsequent CdS Obtention

7.4K 次观看.  Universidad Autónoma del Estado de Hidalgo. 本文提出了一种用化学浴沉积法合成双 (硫脲) 镉氯化物晶体的协议。两个实验被描述: 一个由紫外光辅助与没有紫外光的一。

视频: The Effect of Ultraviolet Radiation on the Chemical Bath Deposition of Bisthiourea Cadmium Chloride Crystals and the Subsequent CdS Obtention

Compact Quantum Dots for Single-molecule Imaging

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology 1-4. To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study.
Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation 5. Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large 4,6,7.
Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past 8,9. The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an insulating CdyZn1-yS shell, further coated with a multidentate polymer ligand modified with short polyethylene glycol (PEG) chains (Figure 1). Compared with conventional CdSe nanocrystals, HgxCd1-xSe alloys offer greater quantum yields of fluorescence, fluorescence at red and near-infrared wavelengths for enhanced signal-to-noise in cells, and excitation at non-cytotoxic visible wavelengths. Multidentate polymer coatings bind to the nanocrystal surface in a closed and flat conformation to minimize hydrodynamic size, and PEG neutralizes the surface charge to minimize nonspecific binding to cells and biomolecules. The end result is a brightly fluorescent nanocrystal with emission between 550-800 nm and a total hydrodynamic size near 12 nm. This is in the same size range as many soluble globular proteins in cells, and substantially smaller than conventional PEGylated QDs (25-35 nm).

We describe the preparation of colloidal quantum dots with minimized hydrodynamic size for single-molecule fluorescence imaging. Compared to conventional quantum dots, these nanoparticles are similar in size to globular proteins and are optimized for single-molecule brightness, stability against photodegradation, and resistance to nonspecific binding to proteins and cells.

紧凑型量子点的单分子成像

Single-molecule imaging is an important tool for  understanding the mechanisms of biomolecular function and for visualizing the  spatial and temporal ...

科研

工程学

Harvesting Solar Energy by Means of Charge-Separating Nanocrystals and Their Solids

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials offering a superior control over the spatial distribution of charge carriers across material interfaces. As this study demonstrates, a combination of donor-acceptor nanocrystal (NC) domains in a single nanoparticle can lead to the realization of efficient photocatalytic1-5 materials, while a layered assembly of donor- and acceptor-like nanocrystals films gives rise to photovoltaic materials.
Initially the paper focuses on the synthesis of composite inorganic nanocrystals, comprising linearly stacked ZnSe, CdS, and Pt domains, which jointly promote photoinduced charge separation. These structures are used in aqueous solutions for the photocatalysis of water under solar radiation, resulting in the production of H2 gas. To enhance the photoinduced separation of charges, a nanorod morphology with a linear gradient originating from an intrinsic electric field is used5. The inter-domain energetics are then optimized to drive photogenerated electrons toward the Pt catalytic site while expelling the holes to the surface of ZnSe domains for sacrificial regeneration (via methanol). Here we show that the only efficient way to produce hydrogen is to use electron-donating ligands to passivate the surface states by tuning the energy level alignment at the semiconductor-ligand interface. Stable and efficient reduction of water is allowed by these ligands due to the fact that they fill vacancies in the valence band of the semiconductor domain, preventing energetic holes from degrading it. Specifically, we show that the energy of the hole is transferred to the ligand moiety, leaving the semiconductor domain functional. This enables us to return the entire nanocrystal-ligand system to a functional state, when the ligands are degraded, by simply adding fresh ligands to the system4.
To promote a photovoltaic charge separation, we use a composite two-layer solid of PbS and TiO2 films. In this configuration, photoinduced electrons are injected into TiO2 and are subsequently picked up by an FTO electrode, while holes are channeled to a Au electrode via PbS layer6. To develop the latter we introduce a Semiconductor Matrix Encapsulated Nanocrystal Arrays (SMENA) strategy, which allows bonding PbS NCs into the surrounding matrix of CdS semiconductor. As a result, fabricated solids exhibit excellent thermal stability, attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces, and show compelling light-harvesting performance in prototype solar cells7.

A general strategy for the development of charge-separating semiconductor nanocrystal composites deployable for solar energy production is presented. We show that assembly of donor-acceptor nanocrystal domains in a single nanoparticle geometry gives rise to a photocatalytic function, while bulk-heterojunctions of donor-acceptor nanocrystal films can be used for photovoltaic energy conversion.

通过电荷分离纳米晶及其固体收获太阳能

Conjoining different semiconductor materials in a single nano-composite provides synthetic means for the development of novel optoelectronic materials ...

Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded synthesis strategy is used in which spherical seeds of CdSe are prepared first using a hot-injection technique. By controlling the crystal structure of the seed to be either wurtzite or zinc-blende, the subsequent hot-injection growth of CdS off of the seed results in either a rod-shaped or tetrapod-shaped nanocrystal, respectively. The phase and morphology of the synthesized nanocrystals are confirmed using X-ray diffraction and transmission electron microscopy, demonstrating that the nanocrystals are phase-pure and have a consistent morphology. The extinction coefficient and quantum yield of the synthesized nanocrystals are calculated using UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The rods and tetrapods exhibit extinction coefficients and quantum yields that are higher than that of the bare seeds. This synthesis demonstrates the precise arrangement of materials that can be achieved at the nanoscale by using a seeded synthetic approach.

A protocol for the seeded synthesis of rod-shaped and tetrapod-shaped multicomponent nanostructures consisting of CdS and CdSe is presented.

硒化镉/硫化镉棒和纳米四脚合成种子

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded ...

化学

Fabrication of Fully Solution Processed Inorganic Nanocrystal Photovoltaic Devices

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

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

全面解决方案处理的无机纳米晶体光伏器件的制造

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

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

形状-各向异性胶体镉硫纳米结构的 Facet-to-facet 连接

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

Surface Functionalization of Metal-Organic Frameworks for Improved Moisture Resistance

Metal-organic frameworks (MOFs) are a class of porous inorganic materials with promising properties in gas storage and separation, catalysis and sensing. However, the main issue limiting their applicability is their poor stability in humid conditions. The common methods to overcome this problem involve the formation of strong metal-linker bonds by using highly charged metals, which is limited to a number of structures, the introduction of alkylic groups to the framework by post-synthetic modification (PSM) or chemical vapour deposition (CVD) to enhance overall hydrophobicity of the framework. These last two usually provoke a drastic reduction of the porosity of the material. These strategies do not permit to exploit the properties of the MOF already available and it is imperative to find new methods to enhance the stability of MOFs in water while keeping their properties intact. Herein, we report a novel method to enhance the water stability of MOF crystals featuring Cu2(O2C)4&#160;paddle-wheel units, such as HKUST (where HKUST stands for Hong Kong University of Science &#38; Technology), with the catechols functionalized with alkyl and fluoro-alkyl chains. By taking advantage of the unsaturated metal sites and the catalytic catecholase-like activity of CuII ions, we are able to create robust hydrophobic coatings through the oxidation and subsequent polymerization of the catechol units on the surface of the crystals under anaerobic and water-free conditions without disrupting the underlying structure of the framework. This approach not only affords the material with improved water stability but also provides control over the function of the protective coating, which enables the development of functional coatings for the adsorption and separations of volatile organic compounds. We are confident that this approach could also be extended to other unstable MOFs featuring open metal sites.

Robust functional catechol coatings were produced in one step by direct reaction of the material known as HKUST with synthetic catechols under anaerobic conditions. The formation of homogeneous coatings surrounding the entire crystal is ascribed to the biomimetic catalytic activity of Cu(II) dimers on the external surface of the crystals.

金属-有机框架的表面功能化改善防潮性能

Metal-organic frameworks (MOFs) are a class of porous inorganic materials with promising properties in gas storage and separation, catalysis and sensing. ...

Key Factors Affecting the Performance of Sb2S3-sensitized Solar Cells During an Sb2S3 Deposition via SbCl3-thiourea Complex Solution-processing

Sb2S3 is considered as one of the emerging light absorbers that can be applied to next-generation solar cells because of its unique optical and electrical properties. Recently, we demonstrated its potential as next-generation solar cells by achieving a high photovoltaic efficiency of &#62; 6% in Sb2S3-sensitized solar cells using a simple thiourea (TU)-based complex solution method. Here, we describe the key experimental procedures for the deposition of Sb2S3 on a mesoporous TiO2 (mp-TiO2) layer using a SbCl3-TU complex solution in the fabrication of solar cells. First, the SbCl3-TU solution is synthesized by dissolving SbCl3 and TU in N,N-dimethylformamide at different molar ratios of SbCl3:TU. Then, the solution is deposited on as-prepared substrates consisting of mp-TiO2/TiO2-blocking layer/F-doped SnO2 glass by spin coating. Finally, to form crystalline Sb2S3, the samples are annealed in an N2-filled glove box at 300 &#176;C. The effects of the experimental parameters on the photovoltaic device performance are also discussed.

Key Factors Affecting the Performance of Sb2S3-sensitized Solar Cells During an Sb2S3 Deposition via SbCl3-thiourea Complex Solution-processing

This work provides a detailed experimental procedure for the deposition of Sb2S3 on a mesoporous TiO2 layer using a SbCl3-thiourea complex solution for applications in Sb2S3-sensitized solar cells. This article also determines key factors governing the deposition process.

利用SbCl3-硫脲复合溶液处理锑23沉积物对锑2S3敏化太阳能电池性能影响的关键因素

Sb2S3 is considered as one of the emerging light absorbers that can be applied to next-generation solar cells because of its unique optical and electrical ...

A Facile Synthetic Method to Obtain Bismuth Oxyiodide Microspheres Highly Functional for the Photocatalytic Processes of Water Depuration

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of materials is highly related to its photocatalytic performance, it is necessary to standardize the synthetic methods in order to obtain the most functional architectures and, thus, the highest photocatalytic efficiency. Here, we report a reliable route to obtain BiOI microspheres via the solvothermal process, using Bi(NO3)3 and potassium iodide (KI) as precursors, and ethylene glycol as a template. The synthesis is standardized in a 150 mL autoclave, at 126 &#176;C for 18 h. This results in 2-3 &#181;m-sized mesoporous microspheres, with a relevant specific surface area (61.3 m2/g). Shortening the reaction times in the synthesis results in amorphous structures, while higher temperatures lead to a slight increase in the porosity of the microspheres, with no effect in the photocatalytic performance. The materials are photo-active under UV-A/visible light irradiation for the degradation of the antibiotic ciprofloxacin in water. This method has demonstrated to be effective in interlaboratory tests, obtaining similar BiOI microspheres in Mexican and Chilean research groups.

This article describes a synthetic method to obtain bismuth oxyiodide microspheres, which are highly functional to perform the photocatalytic removal of organic pollutants, such as ciprofloxacin, in water under UV-A/visible light irradiation.

一种用于水降解光催化过程的高效双氧化二碘微球合成方法

Bismuth oxyhalide (BiOI) is a promising material for sunlight-driven-environmental photocatalysis. Given that the physical structure of this kind of ...

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in Cu(In,Ga)Se2 Thin-film Solar Cells

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes normally result in very poor cell performance. Embedding or sandwiching silver nanowires using moderately conductive transparent materials, such as indium tin oxide or zinc oxide, can improve cell performance. However, the solution-processed matrix layers can cause a significant number of interfacial defects between transparent electrodes and the CdS buffer, which can eventually result in low cell performance. This manuscript describes how to fabricate robust electrical contact between a silver nanowire electrode and the underlying CdS buffer layer in a Cu(In,Ga)Se2 solar cell, enabling high cell performance using matrix-free silver nanowire transparent electrodes. The matrix-free silver nanowire electrode fabricated by our method proves that the charge-carrier collection capability of silver nanowire electrode-based cells is as good as that of standard cells with sputtered ZnO:Al/i-ZnO as long as the silver nanowires and CdS have high-quality electrical contact. The high-quality electrical contact was achieved by depositing an additional CdS layer as thin as 10 nm onto the silver nanowire surface.

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in CuIn,GaSe2 Thin-film Solar Cells

In this protocol, we describe the detailed experimental procedure for the fabrication of a robust nanoscale contact between a silver nanowire network and CdS buffer layer in a CIGS thin-film solar cell.

在 Cu(In、Ga)Se2薄膜太阳能电池中制造银纳米线电极与 CdS 缓冲层之间的强健纳米级接触

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes ...

Close-Space Sublimation-Deposited Ultra-Thin CdSeTe/CdTe Solar Cells for Enhanced Short-Circuit Current Density and Photoluminescence

Developments in photovoltaic device architectures are necessary to make solar energy a cost-effective and reliable source of renewable energy amidst growing global energy demands and climate change. Thin film CdTe technology has demonstrated cost-competitiveness and increasing efficiencies due partially to rapid fabrication times, minimal material usage, and introduction of a CdSeTe alloy into a ~3 &#956;m absorber layer. This work presents the close-space sublimation fabrication of thin, 1.5 &#181;m CdSeTe/CdTe bilayer devices using an automated in-line vacuum deposition system. The thin bilayer structure and fabrication technique minimize deposition time, increase device efficiency, and facilitate future thin absorber-based device architecture development. Three fabrication parameters appear to be the most impactful for optimizing thin CdSeTe/CdTe absorber devices: substrate preheat temperature, CdSeTe:CdTe thickness ratio, and CdCl2 passivation. For proper sublimation of the CdSeTe, the substrate temperature prior to deposition must be ~540 &#176;C (higher than that for CdTe) as controlled by dwell time in a preheat source. Variation in the CdSeTe:CdTe thickness ratio reveals a strong dependence of device performance on this ratio. The optimal absorber thicknesses are 0.5 &#956;m CdSeTe/1.0 &#956;m CdTe, and non-optimized thickness ratios reduce efficiency through back-barrier effects. Thin absorbers are sensitive to CdCl2 passivation variation; a much less aggressive CdCl2 treatment (compared to thicker absorbers) regarding both temperature and time yields optimal device performance. With optimized fabrication conditions, CdSeTe/CdTe increases device short-circuit current density and photoluminescence intensity compared to single-absorber CdTe. Additionally, an in-line close-space sublimation vacuum deposition system offers material and time reduction, scalability, and attainability of future ultra-thin absorber architectures.

This work describes the complete fabrication process of thin absorber cadmium selenium telluride/cadmium telluride photovoltaic devices for enhanced efficiency. The process utilizes an automated in-line vacuum system for close-space sublimation deposition that is scalable, from fabrication of small area research devices as well as large-scale modules.

近空间升升-沉积超薄CDSeTe/CdTe太阳能电池，增强短路电流密度和光致发光

Developments in photovoltaic device architectures are necessary to make solar energy a cost-effective and reliable source of renewable energy amidst ...

紫外辐射对双 (硫脲) 氯化镉晶体化学镀液沉积的影响及随后的 CdS 获得

摘要

探索更多视频

此视频中的章节