L.E. Trujillo and F.J. Willars Rodr&#237;guez thank CONACYT for their scholarships. E.A. Chavez-Urbiola thanks CONACYT for the &#34;Catedras CONACYT&#34; program. Authors also acknowledge the technical assistance of C.A. Avila Herrera, M. A. Hern&#225;ndez Landaverde, J.E. Urbina Alv&#225;rez, and A. Jim&#233;nez Nieto.

CAUTION: The chemicals used in this protocol are toxic and carcinogenic; thus, the safety recommendations and procedures must be followed carefully. Wear proper protective equipment and consult any relevant materials safety data sheet (MSDS).
1. Synthesis of Bis(thiourea) Cadmium Chloride
<ol>
	<li>Preparation of the precursor solution
	<ol>
		<li>Pour 500 mL of deionized water into a 1 L beaker with constant agitation; add 0.3 mL of hydrochloric acid at a 36.5% concentratio...

<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>

The discussion presented in this section focuses only on the protocol and not on the results already shown in the representative results.
One of the most critical parts of the protocol is the preparation of the precursor solution. It is fundamental to maintain an acidic pH to avoid the Cd(OH)2 formation. If the pH is not acidic, it leads to the direct formation of CdS due to the thiourea dissociation and the Cd(OH)2 formation. 
The second most important step is step ...

An important area of research is single crystals; their growth is aimed at different applications. These can be used as non-linear optical materials applied in the areas of laser technology, in the field of optoelectronics, and for the storage of information1, which provides an area of opportunity for their investigation. Bis(thiourea) cadmium chloride is a metal-organic material and can be synthesized from two precursors, thiourea and cadmium chloride, obeying the following chemical formula: 2CS(NH2)2 + CdCl2 CdCl2-[CS(NH2)2]2. This metal-organic material has been prepared under different reaction conditions, such as temperature and pH, but never with the assistance of ultraviolet (UV) light.
The influence of pH on the structure of the crystal has been reported; at a pH &#60; 6, it is possible to obtain the formation of monocrystals. These, in turn, are modified depending on the pH range. At an interval of 6 to 4, it is possible to obtain hexagonal structures, for if pH is &#60; 4, an orthorhombic crystalline structure is obtained2. The ion dissociation is promoted by the acidic pH Cd2+ and Cl- since it prevents cadmium hydroxide formation [Cd(OH)2]. This stabilizes the cadmium: a cadmium atom joins with two sulfur-free radicals and two chlorines.
Here, the synthesis is carried out using the chemical bath deposition technique (CBD), controlling the different conditions that intervene at the time of the chemical reaction3. In CBD, the factors that control the chemical reaction are the following: the solution temperature, the precursor ions, the solution pH, the number of reagents, and the agitation speed, to name a few. On the other hand, the compared technique used here is called photochemical bath deposition (PCBD) because it uses UV light assistance. There have been reports in which UV light assistance has been used to synthesize films of CuSx4,5, ZnS6, CdS7, and InS8, among others. Ichimura and Gunasekaran9 present in their work that sulfate solutions have an absorption edge close to 300 nm. Due to this absorption range, ultraviolet radiation is applied, which results in a similar emission range to that of the absorbed solutions.
Another property of bis(thiourea) cadmium chloride is its degradation when heated. It exhibits an initial decomposition at temperatures of 512 K and above, forming cadmium sulfide (CdS). The degradation reaction is as follows: [Cd(CS[NH2])2]Cl2 &#8594; &#916; CdS + HNCS + NH3 + NH4SCN. This degradation generates thiocyanuric acid and various thiocyanates10,11. Also, in the research group, some effects caused by the UV radiation were studied12. Last, in this work, a comparative synthesis procedure for bis(thiourea) cadmium chloride crystals is described, as well as the effects of UV light.

<table>
	<tbody>
		<tr>
			<td>Reagents</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 &#8211; 38.0 %</td>
			<td>J.T.Baker</td>
			<td>MFCD00011324</td>
			<td>Highly corrosive liquid</td>
		</tr>
		<tr>
			<td>Material</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&#176; Angle, Wide Top. Type I, Class B.</td>
		</tr>
		<tr>
			<td>Watch glasses</td>
			<td>Pyrex</td>
			<td>9985-150</td>
			<td>Corning, 150&#160;mm</td>
		</tr>
		<tr>
			<td>Crucibles</td>
			<td>Fisherbrand</td>
			<td>FB-965-D</td>
			<td>High-Form Porcelain</td>
		</tr>
		<tr>
			<td>Equipment</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

In this work, the effects on the preparation of bis(thiourea) cadmium chloride crystals when illuminated with ultraviolet (UV) light at a wavelength of 367 nm using the chemical bath deposition technique are studied comparatively. Two experiments are performed to make a comparison: one without UV light and the other with the aid of UV light. Both experiments are performed under equal conditions, at a temperature of 343 K and with a pH of 3.2. The precursors used are cadmium chloride (CdCl2) and thiourea [CS(NH2)2], which are dissolved in 50 mL of deionized water with an acidic pH. In this experiment, the interaction of electromagnetic radiation is sought at the moment the chemical reaction is carried out. The results demonstrate the existence of an interaction between the crystals and the UV light; the UV light assistance causes crystal growths in an acicular shape. Also, the final product obtained is cadmium sulfide and shows no evident difference when synthesized with or without the use of UV light.

The UV-Vis diffusion&#39;s reflectance absorption spectra in both precursor solutions, A and B, show the existence of a bis(thiourea) cadmium chloride complex&#8212;CdCl2-(CS(NH2)2)2. This is evidenced by a broad absorption band within the range of 250 - 500 nm in Figure 2c. In turn, Figure 2c is the combination of the main absorption bands of the isolated CdCl2 and CS(NH<sub...

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

This article presents a protocol for the synthesis of bis(thiourea) cadmium chloride crystals by chemical bath deposition. Two experiments are described: one aided by ultraviolet light compared to one without ultraviolet light.

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

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

This method can help answer key questions on the crystal world-field. Such as interaction of UV light and the world of bis-thiourea cadmium chloride crystals. The main advantage of this technique is that it's possible to modify the morphology of bis-thiourea cadmium chloride crystals.Demonstrating the procedure will be MCM Luis Eduardo Trujillo-Villanueva. A grad student of our laboratory. First, pour 500 milliliters of deionized water into a one liter beaker, with constant agitation.Then add 3 milliliters of 36.5%hydrochloric acid. Making sure that the ph of this solution is as close as possible to three. Next, pour 50 milliliters of the pre-cursor solution into two 100 milliliter beakers labeled A and B.Add 2.29 grams of cadmium chloride and 1.33 grams of thiourea in each beaker.Following this, place beaker A on a stirring hot plate and heat to 334 kelvin;with moderate stirring speed for two hours. Place beaker B on a stirring hot plate and heat to 334 kelvin, with moderate stirring. Turn on the UV light source and allow the reaction to proceed for two hours.Place a glass funnel with filter paper on two 100 milliliter volumetric flasks. Immediately filter each solution from beakers A and B, into separate flasks. Filter the solutions quickly, because the cooling initiates the crystal growth.Now allow both solutions to cool to room temperature. Place a glass funnel with filter paper on two new 100 milliliter volumetric flasks. Filter the solutions with the crystals into separate flasks.Transfer the crystals from the filter paper to separate watch glasses. Place the crystals into two separate crucibles labeled A and B.Preheat an electric laboratory furnace and stabilize its temperature at 773 kelvin or higher. Once the furnace temperature is stabilized, place the crucibles containing the crystals inside the furnace.After one hour, turn off the furnace and allow it to cool to room temperature. Then remove the crucibles containing the crystals from the furnace. The UV-vis diffusions reflectance absorption spectra in both pre-cursor solutions, show the bis-thiourea cadmium chloride complex, which is evidenced by a broad absorption band from 250 to 500 nanometers.The cadmium chloride and thiourea absorption bands are also observed in the spectra of the complex. The Raman spectra of the crystals display peaks corresponding to the cadmium chlorine nitrogen carbon sulfur and carbon sulfur bonds. Although the same bonds are observed for both experiments, such intensities are lower without UV assistance.Which indicates a smaller number of bonds. The XRD pattern shows preferential growth in the zero two zero and zero zero one planes with UV light;which corresponds to sulfur and cadmium atoms, within the complex, respectively. The SEM images show that acicular crystals, four to six times larger, are formed with UV light.TGA analysis of the crystals exhibits a similar behavior for both the UV and non-UV assisted experiments. DRX of the calcium complex shows no differences in the cadmium sulfide, obtained by chemical bath deposition versus photo-chemical bath deposition. A slightly more prominent average particle size for photo-chemical bath deposition is observed.Demonstrating that UV light promotes sulfur incorporation into the cadmium. The UV light promotes chemical balance between cadmium and sulfur-ions, which causes preferential growth in the crystallized total of the bis-thiourea cadmium chloride crystals. The cadmium sulfide obtained after calcination showed no evident difference.

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

Research

JoVE Journal

Chemistry

7.3K vues.  Universidad Autónoma del Estado de Hidalgo. This method can help answer key questions on the crystal world-field. Such as interaction of UV light and the world of bis-thiourea cadmium chloride crystals. The main advantage of this technique is that it's possible to modify the morphology of bis-thiourea cadmium chloride crystals.Demonstrating the procedure will be MCM Luis Eduardo Trujillo-Villanueva. A grad student of our laboratory. First, pour 500 milliliters of deionized water into a one liter beaker, with constant agitation.