# Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties

S Karthick, A Albert Irudayaraj, A Dhayal Raj, R Vinayagamoorthy

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S Karthick, A Albert Irudayaraj, A Dhayal Raj, R Vinayagamoorthy. Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties. Mechanics, Materials Science & Engineering Journal, 2017, 9, 10.2412/mmse.66.68.799. hal-01503830

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# Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties

S. Karthick¹ª, A. Albert Irudayaraj¹, A. Dhayal Raj¹, R. Vinayagamoorthy¹

1 – PG and Research Department of Physics, Sacred Heart College, Tirupattur, Vellore Dist., India

a – s.karthick5583@gmail.com

<figure><img src="image_2.png" /></figure>

DOI 10.2412/mmse.66.68.799 provided by [Seo4U.link](https://link.springer.com/10.2412/mmse.66.68.799)

**Keywords:** organometallic crystal, FTIR, UV-Vis, TG/DTA, NLO.

**ABSTRACT.** Cadmium Dimethyl Sulfoxide Thiocyanate (CDST) organometallic crystal was grown from aqueous solution. The grown CDST crystals are characterized by single X-ray diffraction for structural analysis. Fourier Transformation Infrared analysis confirms the presence of functional groups in the CDST. UV-Visible analysis reveals that CDST is about 90% transparent in the entire visible region and UV lower cutoff wavelength is 236 nm. TGA and DTA studies reveal the physicochemical stability of the CDST and NLO study by Kurtz – Perry powder technique reveals that the CDST exhibits emission of green light and the second harmonic generation efficiency of CDTS was 1.2 times that of KDP.

**Introduction.** Nonlinear optical frequency conversion materials play a vital role in optical communication, optical data storage and laser technology. Most of organometallic materials are suitable for nonlinear optical application due to better physical stability and second harmonic generation efficiency. Bimetallic Thiocyanate derivative crystals such Zinc Cadmium Thiocyanate (ZCTC) [1], Zinc Mercury Thiocyanate (ZMTC) [2], Cadmium Mercury Thiocyanate (CMTC) [3], Manganese Mercury Thiocyanate (MMTC) [4], etc., have been reported as dynamic Second Order Nonlinear Optical (SONLO) Materials. Some of Lewis base adducts thiocyanate derivative crystals such as Cadmium Mercury Thiocyanate dimethyl Sulfoxide (CMTD) [5], Cadmium Mercury Thiocyanate glycol mono methyl ether (CMTG) [6], Manganese Mercury Thiocyanate dimethyl Sulfoxide (MMTD) [7], Manganese Mercury Thiocyanate glycol mono methyl ether (MMTG) [8], etc., have been reported that large growth rate and better Nonlinear efficient but the thermal stability is decrease compared to the their bimetallic thiocyanate derivative crystals. Metal organic crystals such as bis-thiourea cadmium chloride, Allylthiourea cadmium chloride, tris (thiourea) zinc Sulphate, Ammonium (18- crown-6-ether) Cadmium Tri thiocyanate, etc., have been reported with good Nonlinear optical properties and moderate physical stability. X.Q. Wang et al., grown the bis (dimethyl sulfoxide) cadmium thiocyanate by temperature lowering method and characterized by Single crystal XRD, FTIR, UV-Visible and thermal analysis [9]. In the present work, Cadmium Dimethyl Sulfoxide Thiocyanate (CDST) organometallic crystal was grown by solvent evaporation method using water-DMOS has a mixed solvent. Structural, optical and thermal properties are reported and discussed.

**Synthesis and crystal growth of CDST.** Commercially available AR grade chemicals were used as the stating materials. The synthesis of the Cadmium Dimethyl Sulfoxide Thiocyanate (CDST) was carried out by carefully incorporating the stoichiometric amount of Cadmium chloride, Potassium Thiocyanate and Dimethyl Sulfoxide in appropriate ratio using the chemical reaction give below:
$$2KSCN + CdCl_2 + 2C_2H_6SO \rightarrow Cd(SCN)_2(C_2H_6SO)_2$$

Pale red solution was kept undisturbed at room temperature. White precipitated of CDST was separated from the bottom of the solution. The saturated solution of CDST was prepared and kept for solvent evaporation at room temperature. Good transparent crystals were grown in the period of three weeks. To ensure the purity, recrystallization was carried out twice. The as grown harvested CDST crystals are shown in the fig. 1.

**Characterizations.** The grown CDST crystals had been subjected to single crystal X-ray diffraction analysis was carried out using RIGAKU with SATRUN 724 plus detector and molybedum as source at room temperature to confirm the crystallographic system. Fourier transformation infrared analysis was carried out using PERKIN ELMER FTIR spectrum II spectrometer using KBr pellet to confirm the presence of various functional groups of CDST. UV – Visible analysis was carried out using Varian Cary 50 Bio UV – Vis spectrophotometer to confirm optical energy gap. TG/DT analysis was carried out using NETZSCH STA 409C thermal analyzer to reveal the thermal stability of CDST. Nonlinear optical property of the powder CDST crystal was estimated by Kurtz – perry powder technique using Q-switched Nd:YAG laser of wavelength 1064nm and Second Harmonic Generation efficiency is compared with KDP.

<figure><img src="image_3.png" /><figcaption>Fig. 1. As-grown crystal of CDST.</figcaption></figure>

**Single crystal X-ray diffraction analysis.** The grown good quality CDST crystal was selected for the single crystal X-ray diffraction analysis. The result of CDST reveals that, it is belongs to Triclinic system with space group P1 which is recognized as noncentrosymmetric, thus satisfying one the basic and essential material requirements for the SHG activity of the crystal. The lattice Parameters of CDST crystal are, a= 5.9115 Å, b= 8.053 Å, c= 8.133 Å, α = 114.371°, β = 100.58° and γ =95.661°. This result coincides with early reported of X.Q. Wang et al., [9].

**Fourier transformation infrared analysis.** When infrared radiation interacts with a sample, a portion of the incident radiation is absorbed at a specific wavelength and the FTIR absorption spectrum is to confirm of the presence of the functional group of the sample. The FTIR spectrum of the CDST was shown in the Figure 2. The vibrational peaks at 3008 and 1403 cm⁻¹ is due to C-H symmetric stretching presence in DMOS. The peak at 2101cm⁻¹ is due to C-N asymmetric stretching vibration which is presence in thiocyanate molecule. The peaks appear at 1314 and 1000cm⁻¹ is due SCN rocking, which confirms the presences of thiocyanate. The peak 957 cm⁻¹ is due S-O stretching vibration. The absorption occurs at 770 and 709 cm⁻¹ is due C-S deformation. The peaks at 467 and 412 cm⁻¹ due to presence of S-C≡N bend of thiocyanate.
<figure><img src="image_4.png" /><figcaption>Fig. 2. FTIR spectrum of CDST.</figcaption></figure>

**UV-visible analysis.** For optical applications, especially for SHG the material considered must be transparent in the wavelength region of applicant. UV-Visible spectrum of CDST was shown in the figure 3. For the CDST, UV-Visible spectral was recorded the region 200 to 800 nm. The result reveals that the CDST is transparent about 90% in the entire visible region. The lower cutoff wavelength of CDST is found to be 236nm and optical band gap of the material is 5.3 eV.

<figure><img src="image_5.png" /><figcaption>Fig. 3. UV-Visible Spectrum of CDST.</figcaption></figure>

**Second harmonic generation measurement.** The grown crystal of CDST was powdered to a uniform particle size and then packed in a micro-capillary of uniform bore and exposed to Nd:YAG laser radiations. The generation of the second harmonic was confirmed by the emission of green light. The second harmonic generation (SHG) output power from CDST is found to be about 7.2 mV for
the input energy of 1.2 mJ /pulse. The SHG output power from KDP is found to be 6 mV. The SHG efficiency of the CDST is 1.2 that of KDP.

**Thermal analysis.** The good quality crystal of CDST was powdered and taken in the definite amount, to study the thermal property of the CDST material. The TG/DTA curves were shown in the figure 4. From TGA curve, it reveals that the first weight loss of 10% at 85°C due to water evaporation which was absorbed by sample from the atmosphere. There after no weight loss was founded up to 150° C, after that sudden weight loss of 65% was founded. Which indicate that the CDST was suitable up to 150°C. In DTA curve, a exothermic and a endothermic peak was founded. The board exothermic peak at 85°C due to water evaporation from the sample. The sharp endothermic peak at 168 °C indicated the melting point of the material.

<figure><img src="image_6.png" /><figcaption>Fig. 4. TG/DTA curve of CDST.</figcaption></figure>

**Summary.** Cadmium Dimethyl Sulfoxide Thiocyanate was successful synthesis in stoichiometric ratio. Cadmium Dimethyl Sulfoxide Thiocyanate crystal was grown by slow evaporation method. Single crystal XRD analysis reveals that CDST crystal belongs to Triclinic system with space group P1. The FTIR analysis confirms that presence on functional groups in CDST. UV-Visible analysis reveals that CDST is transparent about 90% in the entire visible region and optical energy band gap of 5.3 eV. The second harmonic generation efficiency of the CDST is 1.2 that of KDP. The TG/DTA reveals that CDST is thermally stable up to 168°C. CDST crystal has wide range transparent region, moderate thermal property and better second harmonic generation efficiency, which are essential properties need for optical communication and fabrication of optical storage devices.

**Refernces**

[1] Xinqiang Wang, Dong Xu, Mengkai Lu, Dourong Yuan, Guanghui Zhang, Shouxi Xu, Shiyi Guo, Xuening Jiang, Jiurong Liu, Chunfeng Song, Quan Ren, Ji Huang, Yupeng Tian., 2001, Growth and properties of UV nonlinear optical crystal ZnCd(SCN)4, Materials Research Bulletin vol. 36, 1287-1299, S0025-5408(01)00598-0.

[2] K. Ambujam, S. Selvakumar, Ginson P. Joseph, I. Vetha Potheher, P. Sagayaraj, 2007, Thermal, Optical, and Electrical Properties of Gel Grown ZMTC, Materials and Manufacturing Processes, vol. 22, 351-356, 10.1080/10426910701190766.
[3] P. Paramasivam, C. Ramachandra Raja, 2011, Synthesis, growth and characterization of cadmium manganese thiocyanate (CMTC) crystal, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 79, 1109-1111, 10.1016/j.saa.2011.04.028.

[4] M. Manikandan, G. Vijaya Prasath, G. Bhagavannarayan, N. Vijayan, T. Mahalingam, G. Ravi, 2012, Structural, spectral and mechanical studies of bimetallic crystal: cadmium manganese thiocyanate single crystals, *Applied Physics A materials science and processing* vol. 108, 1015-1020, 10.1007/s00339-012-7015-2.

[5] ShiyiGuo, DuorongYuan, DongXu, GuanghuiZhang, SuoyingSun, FanqingMeng, Xinqiang Wang, XueningJiang, MinhuaJiang, 2000, Growth of Cadmium Mercury Thiocyanate Dimethyl Sulfoxides in Gel Crystal For Laser Frequency Doubling, Progress in Crystal Growth and Characterization of Materials, 75-79, S0960-8974(00)00019-X.

[6] S. Cynthi, B. Milton Boaz, 2013, Synthesis and characterization of a novel non-linear optical crystal Cadmium mercury thiocyanate glycol mono methyl ether, *International Journal of Engineering Science Invention*, vol.2, 38-43.

[7] X.Q. Wanga, D. Xua, M.K. Lua, D.R. Yuana, S.X. Xub, S.Y. Guoa, G.H. Zhanga, J.R. Liua, 2001, Crystal growth and characterization of a novel organometallic nonlinear-optical crystal: MnHg(SCN)4(C2H6OS)2, *Journal of Crystal Growth*, 224, 284-293, S 0 0 2 2 - 0 2 4 8 ( 0 1 ) 0 1 0 1 2 - 0.

[8] Ginson P. Joseph, N. Melikechi, Jacob Philip, J. Madhavan, P. Sagayaraj, 2009, Studies on the electrical, linear and nonlinear optical properties of Manganese mercury thiocyanate bis(dimethyl Sulfoxide) an efficient NLO crystal, *Physica B*, vol.404, 295-299, 10.1016/j.physb.2008.10.055.

[9] X.Q. Wanga, D. Xu, D.R. Yuan, M.K. Lu, X.F. Cheng, J. Huang, G.W. Lu, S.Y. Guo, G.H. Zhang, 2002, Growth, spectroscopic and thermal behavior of Cd(SCN)2(DMSO)2, *Journal of Crystal Growth*, vol. 246, 155-160, S0022-0248(02)01763-3.

Cite the paper

S. Karthick, A. Albert Irudayaraj, A. Dhayal Raj, R. Vinayagamoorthy (2017). Cadmium Dimethyl Sulfoxide Thiocyanate NLO Crystal: Structural, Optical and Thermal Properties. Mechanics, Materials Science & Engineering, Vol 9. Doi 10.2412/mmse.66.68.799