Accepted Manuscript Nucleation, Growth and Characterization of semiorganic nonlinear optical crystal L-tyrosine sodium acetate (LTSA) D. Arthi, D. Anbuselvi, D. Jayaraman, J. Arul Martin Mani, V. Joseph PII: DOI: Reference:

S1386-1425(14)01308-0 http://dx.doi.org/10.1016/j.saa.2014.08.117 SAA 12638

To appear in:

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Received Date: Revised Date: Accepted Date:

30 May 2014 30 July 2014 24 August 2014

Please cite this article as: D. Arthi, D. Anbuselvi, D. Jayaraman, J. Arul Martin Mani, V. Joseph, Nucleation, Growth and Characterization of semiorganic nonlinear optical crystal L-tyrosine sodium acetate (LTSA), Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (2014), doi: http://dx.doi.org/10.1016/j.saa.2014.08.117

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Nucleation, Growth and Characterization of semiorganic nonlinear optical crystal L-tyrosine sodium acetate (LTSA) D. Arthi a,* D.Anbuselvi a, D. Jayaramanb, J.Arul Martin Mani a, V.Joseph a a Department of Physics, Loyola College, Chennai, Tamil Nadu, India b Department of Physics, Presidency College, Chennai, Tamil Nadu, India Abstract L-tyrosine sodium acetate (LTSA) single crystal with dimensions 47 × 15 × 8 mm 3 was grown by slow evaporation solution growth technique. Nucleation kinetics of the growth of the material was studied to optimize the growth conditions. The grown crystal was then characterized using single crystal XRD, UV-Vis-NIR, FTIR, NMR, SEM-EDAX and NLO studies. XRD study reveals that the grown crystal belongs to monoclinic system with space group P21. Lattice SDUDPHWHUVRIWKHJURZQFU\VWDOVDUHIRXQGWREHD ǖE ǖF ǖĮ ȕ  DQGȖ  . The transparent range of the grown crystal was measured as 260-1100 nm with 260 nm as lower cut off wavelength using UV-vis-NIR absorption spectrum and the optical band JDSZDVHYDOXDWHGDVH9IURPWKH7DXF¶VSORW7KHYDULRXVIXQFWLRQDOJURXSVZHUHLGHQWLILHG using FTIR spectral analysis. The thermal behaviour of L-tyrosine sodium acetate has been analyzed using TGA/DTA and DSC thermal curves. From the thermal study, the material is found to possess thermal stability up to 158 .The microstructure of the grown crystal and the presence of various elements in the crystal were analyzed using SEM and EDAX techniques. NMR spectral analysis confirms the molecular structure of the grown compound. The nonlinear optical property was tested using Kurtz Perry powder technique and SHG efficiency was measured nearly same as that of KDP. Keywords: Single crystal, FTIR spectroscopy, Nonlinear optics, Thermogravimetric analysis. *Corresponding Author: D. Arthi Department of Physics, Loyola College,Chennai ± 600 034. Mobile No. 9751950807, Email: [email protected]

1. Introduction In modern world, the development of science in many areas has been achieved through the growth of single crystals. Nonlinear optical materials play a vital role in the technology of photonics including optical information processing. Many research efforts are undertaken to synthesise and characterize new molecules for second order NLO applications such as highspeed information processing, optical communication and optical data storage [1-4]. Amino acids are interesting organic materials for NLO applications. They exist as zwitterions as they contain a proton donor carbonyl acid group (COOH) and a proton acceptor (NH2) group. Attempts have been made to combine amino acid with various metallic compounds to produce complexes having large polarizability and NLO activity. As a result, it is possible to develop a new class of materials called organo-metallics. These materials have the advantages of combining high optical nonlinearity and chemical flexibility of organic materials with thermal stability and mechanical robustness of metallic compounds [5-8]. In the present work, a new amino acid complex material L-tyrosine sodium acetate (LTSA) has been grown and characterized using various studies. The classical nucleation theory was used to optimize the growth conditions with a view to improve the quality and size of the crystal. The growth of the crystal is followed by detailed characterisation studies which include single crystal XRD, UV-Vis-NIR, FTIR, NMR, SEM-EDAX, and NLO studies. 2. Experimental procedure 2.1 Synthesis and growth of LTSN L-tyrosine sodium acetate was synthesized by dissolving L-tyrosine and sodium acetate in deionised water with stoichiometric ratio of 1:2. The chemical reaction is given as follows: C9H11NO3+2(C2H3NaO2)

C9H11NO3 2(C2H3NaO2)

The starting materials were dissolved in mixed solvent of hydrochloric acid-water according to stoichiometric ratio. The solution was continuously stirred with a magnetic stirrer for about 24 hrs to attain homogeneity and the solution was allowed to undergo slow evaporation which gradually led to supersaturated condition for the nucleation of crystal phase resulting in the formation of tiny crystals. The crystallization process was repeated three times to improve the size and quality of the crystal. After a period of 25 days, single crystals of LTSA with dimensions of 47 x 15x 8 mm3 were harvested successfully. The photograph of the as-grown crystal is shown in Fig .1. 3. Nucleation kinetics 3.1 Classical nucleation theory (CNT) When a crystal nucleus of LTSA is formed in the mother solution due to supersaturation, WKHFKDQJHLQ*LEEVIUHHHQHUJ\ǻ* LVZULWWHQDV 'G

'GS  'GV

(1)

ZKHUHǻ*S LVWKHVXUIDFHH[FHVVIUHHHQHUJ\DQGǻ*V is the volume excess free energy. When the crystal nucleus is formed well within the mother phase, the type of nucleation is termed as homogeneous nucleation. For homogeneous nucleation, the shape of the nucleus is reasonably assumed to be spherical since the nucleus contains few molecules in the initial stage. For the spherical nucleus, 'G

where

4 4Sr 2V D  Sr 3'Gv 3

(2)

is the interfacial or surface energy per unit area DQG ǻ*Y LV WKH YROXPH IUHH HQHUJ\

change per unit volume and it is a negative quantity. According to classical nucleation theory, the surface energy

is assumed to be same throughout nucleation for simplicity. This is called

capillarity approxLPDWLRQ$VWKHQXFOHXVJURZVLQVL]Hǻ*LQFUHDVHVDWWDLQVPD[LPXPDQGWKHQ starts decreasing. The size corresponding to maximum free energy change is called critical QXFOHXV $W WKH FULWLFDO VWDJH WKH FRQGLWLRQ Gǻ* GU   LV DSSOLHG WR REWDLQ WKH UDGius of the critical nucleus (r* DQGFULWLFDO*LEEVIUHHHQHUJ\FKDQJHǻ**). The expressions for nucleation parameters are thus obtained as  2V D 'Gv

r*

(3)

and

16SV D 2 3'Gv

3

'G*

(4)

The number of critical nuclei formed per unit time per unit volume is known as nucleation rate. The nucleation rate, according to Zeldovich and Frenkel [9] is given as

J

ZES (i*)C (i*)

(5)

where Z is Zeldovich factor or non-HTXLOLEULXP IDFWRU ȕ LV WKH impingement flux, S(i*) is the surface area of the critical nucleus and C(i*) is the concentration of the critical nuclei. The nucleation rate is now written as J

§  'G * · A exp ¨ ¸ © kT ¹

(6)

where the pre-exponential factor

A

§  'Gdiff ZQ ¨¨ exp d2 © kT

· ¸¸4Sr *2 C i D ¹

(7)

The Zeldovich factor for a spherical nucleus was calculated using the following expression given by Turnbull and Fisher [10].

Z

§ 'G * · ¨ ¸ © 3SkT ¹

1

2

(8)

ǻ*diff LVRIWKHRUGHUN7DQG‫ݝ‬LVRIWKHRUGHU13 Hz. C(i)o was calculated from unit cell volume of LTSA. 3.2 Induction period measurement ± Evaluation of surface energy ıo The time interval from the instant the evaporation starts till the observation of the first speck of nucleus is called induction period. The induction periods were measured at temperature 308K for the supersaturation range 1.2 ± 1.60 using constant temperature bath with an accuracy of 0.001 . The induction period (

is related to the steady state nucleation rate

as

at

a particular temperature T. Since the nucleation J is defined as the number of critical nuclei per unit time in a unit volume. We know

J

§  'G * · A exp ¨ ¸ © kT ¹

and

Or

where B is a constant. Taking logarithms on both sides of equation (9)

(9)

(10)

Substituting the value of

, (11)

where v is the specific volume of the crystal,

is the surface energy per unit area, S is the

supersaturation ratio and B is a constant. A plot of ln

versus 1/(ln S)2 (Fig.2) is found to be

linear which is evident from equation (11). From the slope of the plot, the surface energy per unit area was calculated as 6.238 mJ m -2. The surface energy per unit area was also calculated from the following expression given by Nelson et al [11]. (12)

where k is Boltzmann constant, T is the temperature,

is the inter-ionic distance and

mole fraction of the solute at temperature T. The value of data (Fig.3). The inter-ionic distance

is the

was calculated from the solubility

was estimated from the lattice parameters of the crystal.

(13) The value of

was theoretically calculated as 7.120 mJ m-2. Hence, the experimentally

determined value (6.238 mJ m-2) from induction period measurement was found to be closer to the theoretically calculated value (7.120 mJ m-2). Using the value ,

and

were calculated.

3.3 Modified classical nucleation theory (MCNT)

, the nucleation parameters

The classical nucleation theory makes use of the capillarity approximation in which the VXUIDFHHQHUJ\ıo is assumed to be same throughout nucleation for mathematical simplicity. In real situation, the surface energy and other properties will change in the microlevel stage. Rasmussen et al [12] developed a theory for the nucleation kinetic equation incorporating the dependence of interfacial energy on the size of the cluster. After that, Jayaraman et al [13, 14] have obtained the following expression for the surface energy as a function of size of the nucleus using the concept of thermodynamics.

V

ª Gº V D «1  » ¬ r¼

(14)

wKHUHįLVWKHVL]HRIWKHPRQRPHU:KHQıo LVUHSODFHGE\ıLQWKH*LEEVIUHHHQHUJ\FKDQJH equation (2), the capillarity approximation is corrected. After this correction, the expressions for nucleation parameters were modified. Using classical nucleation theory and modified classical nucleation theory, the nucleation parameters have been calculated for the LPMC crystal at different supersaturations and WHPSHUDWXUHV7DEOHSUHVHQWVWKHYDOXHVRIıo, ǻGv, r* and ǻG* using the above theories. It is observed that the volume free energy change per unit volume decreases with supersaturation at a fixed temperature. Consequently, the critical radius (r*) and critical free energy change (ǻG*) decrease with increase of supersaturation. As a result, the nucleation rate increases considerably with increase of supersaturation at a fixed temperature. The supersaturation for which nucleation rate J = 1 is called critical supersaturation (Sc). Fig.4. shows the plots of supersaturation against nucleation rate at room temperature 308 K using classical nucleation theory and modified classical nucleation theory. The predicted critical supersaturations are found to be 1.084 and 1.083 at room temperature 308 K using the classical and modified nucleation theories.

3.4 Optimized growth condition After growing the crystal, the supersaturation of the remaining solution was measured as 1.07. This value lies within the theoretically predicted critical supersaturations (1.084 and 1.083). It is concluded from the experiment that the crystal should be grown well within the critical supersaturation in order to obtain good quality crystals for device fabrications. On the other hand, if the supersaturation exceeds the critical supersaturation, we will end up with polycrystalline material. We are thus able to optimize the initial growth condition for growing good quality crystals. 4. Results and discussion 4.1 Single crystal XRD analysis Single crystal X-ray diffraction analysis has been carried out using an ENRAF Nonius CAD4 diffractrometer with MoKĮ Ȝ  ǖ  UDGLDWLRQ WR LGHQWLI\ WKH FU\VWDO V\VWHP DQG lattice parameters. From the single crystal analysis, it has been observed that the LTSA crystal possesses monoclinic system with non-centrosymmetric space group P21.This space group suggests the grown crystal belongs to non-centrosymmetric group which fulfils the fundamental criterion for NLO behaviour of the material. Lattice parameters of the grown crystals are found WR EH D   ǖ E ǖ DQG F ǖ Į  ȕ

o, Ȗ o and volume

9 ǖ 3. 4.2 Morphology study The photograph of the crystal used for morphology study and its morphology are shown in Figs.5 (a) and (b) respectively. The morphology of the crystal, in general, depends upon the solvent used, temperature, supersaturation of the solution and impurities and additives added to

the growth solution. In the present study, temperature and supersaturation were kept constant and the resulting morphology of the grown crystal was studied. The grown crystal has six well developed faces (0 1, 01 , 001, 00,011, 0

). The growth rate is found to be more along c-axis

than that in the other directions. The well-developed distinct faces clearly ensure the optimized condition during the growth process. 4.3 UV-vis-NIR spectral analysis The optical absorption spectrum of the grown crystal was recorded in the wavelength range 200±2000 nm using a VARIAN CARY 5E spectrophotometer. The absorption spectrum is shown in Fig 6. The low absorption in the UV, entire visible and near infrared regions reveals the wide transparency of the grown crystal in the range of 260-1100nm. From the absorption spectrum, the lower cut off wave length is measured as 260nm. The cut off wavelength for the UV absorption spectrum in the case of LTSA crystal is computed as follows: For COO group: 160 nm For NH2 group: 95 nm For alkyl group: 5 nm Hence, the lower cut off wavelength in the UV region has been computed as (160+95+5) 260 nm which is found to be closer to the experimentally observed value 252 nm from the UV-vis-NIR absorption spectrum [15]. $FFRUGLQJ WR 7DXF¶V UHODWLRQ WKH DEVRUSWLRQ FRHIILFLHQW Į  RI D PDWHULDO LV UHODWHG WR optical band gap (Eg) and photon energy (h ) as [16] (15)

where A is a constant for different transitions and n is an index which assumes the values 1/2,3/2, 2 and 3 depending on the nature of electronic transitions responsible for absorption. The band gap energy value Eg was estimated as 3.24eV from the plot of (

) 2 versus photon energy

(Fig. 7). The optical band gap offers more optical conductivity to the medium without optical photons being absorbed in the specific range of wavelengths. This provides dielectric nature to the material. Only dielectric materials will have wide transparent range. The optical photons have energies in the range of 1 to 3 eV in the UV±vis±NIR region. This range of energy is not sufficient to excite the electrons for transition from valance band to conduction band in the dielectric material. Therefore, the incident optical photons in the range of UV±vis±NIR region are not absorbed by the material and the material is capable of transmitting the light of wavelengths in the range 260±1100 nm. The higher value of optical band gap thus provides sufficient transmitting power required for the NLO activity of the materials. 4.4 FTIR spectrum analysis The FTIR spectral analysis for the grown crystal has been recorded in the range 400±4000 cm-1 using a BRUKKER IFS66v spectrophotometer using the KBr pellet technique and the spectrum is shown in Fig 8. In the FTIR spectrum, the broad band lying between 3784 cm-

1

and 2599 cm- 1are due to the absorption of the superimposed O±H and NH3 stretching

vibrations [17, 18]. The sharp peak at 1587 cm- 1 indicates N-H bending of amide groups. The bands observed at 1514 cm- 1 and 1483 cm- 1 are assigned to symmetrical NH3+ bending vibration, whereas the peaks at 1328 cm- 1 and 1244 cm- 1 are due to NH3 asymmetric wagging vibration respectively. The strong peaks due to1151 cm- 1 and 1102 cm- 1 clearly indicate C-H wagging vibrational alkyl halides. The sharp peak at 839 cm- 1 corresponds to C-Cl stretching of alkyl

halide. FTIR spectral analysis provides the information about the presence of zwitter ions, amide and alkyl halide groups in the grown material LTSA. 4.8 Thermal analysis Thermogravimetric analysis (TGA) differential thermal analysis (DTA) and differential scanning calorimetry (DSC) of LTSA crystal were studied simultaneously using the instrument NETZSCHSTA 409C thermal analyser. A powder sample was used for this analysis in the temperature range of 10-600 C in nitrogen atmosphere at a heating rate of 20 C/min. TGA and

DTA curve for the grown crystal LTSA are shown in Fig.9. From the TGA curve, it is observed that the decomposition starts at 160

due to the dissociation of the compound followed by the

evaporation of volatile products. The weight loss corresponding to 225 C and 320 C are observed as 7.95% and 58.94% respectively. The range of decomposition 160 C - 320 C is also confirmed by the prominent endothermic peaks of DTA curve at 200 C, 260 C, and 288 C. The peak corresponding to 180

refers to the evaporation of trapped water molecules from the

compound. The other peaks at 208 C, 260 C, and 288 C refer to the gradual evaporation of NO2, CO2 and NH3 gas molecules respectively. The decomposition process is almost completed at 375 C with weight loss of 73.13% and this is confirmed by the endothermic peak of DTA curve at the same temperature. The completion of decomposition process is also indicated due to prominent peak at 375oC DSC of curve as shown in Fig.10. This is therefore concluded that the material is thermally stable up to 160 withstand high temperature.

which is suitable for the possible applications in lasers to

4.9 NMR spectral analysis The recorded 1H NMR spectrum is shown in Fig.11. 1H NMR spectrum of LTSA shows five different peaks as expected at different positions due to chemical shift. The chemical shift at į SSPLVGXHWRK\GURJHQDWRPDVVRFLDWHGZLWK&+3 groups. The quartet splitting of three FRXSOHGK\GURJHQDWRPVDUHREVHUYHGDWį DQGSSPUHVSHFWLYHO\ZLWK amine group in the moleculDUVWUXFWXUH7KHWULSOHWSHDNVDWį SSPDUHGXH WR DOLSKDWLF &+ SURWRQV 7KH VLJQDOV DW į   SSP DQG  SSP DUH GXH WR SURWRQ RI WKH carboxyl group (OH) in the compound [19]. Thus the molecular structure of LTSA compound was confirmed by 1H NMR spectral analysis. 4.10 SEM - EDAX analysis Figs.12. (a, b and c) show the SEM images of the grown crystal surface with resolutions 1µm, 5µm and 10µm respectively. The surface features of grown crystal as shown in Fig.12 (a) reveals the smooth surface of the grown crystal with transparent nature. Figs.12 (b) and (c) with higher magnifications 5µm and 10µm show the different sizes of atoms confirming the presence of various components in the grown material. Fig.13 shows EDAX spectrum of LTSA crystal. The presence of the elements C, O, N and Na in different proportions are indicated by the respective peaks. The incorporation of sodium is thus confirmed and the compositions of various elements are shown in Table 2.

4.11 NLO Study Second harmonic generation efficiency of the grown crystal LTSA was estimated using Kurtz and Perry powder technique with the help of Nd : YAG laser beam of wavelength 1064 nm [20]. The crystalline LTSA material was powdered to the particle size in the range 125-150

ȝP7KHFU\VWDOSRZGHUZDVGHQVHO\SDFNHGLQDPLFURFDSLOODU\WXEH7KHODVHULQFLGHQWHQHUJ\ was calculated in terms of mJ using a light meter. The SHG was confirmed from the emission of green radiation of wavelength 532 nm and the optical signal was detected by a photomultiplier tube. The output of the signal was measured as 52 mV and compared with that (56 mV) of KDP. The SHG efficiency of LTSA was found to be 0.93 times that of KDP crystal. 5. Conclusion Good optical quality of LTSA crystals were grown using isothermal slow evaporation method. The lattice parameters have been determined using single crystal X-ray diffraction technique. The microstructure of LTSA was analyzed using SEM photograph. The various elements present in the crystal were identified using EDAX analysis. The transparent range and the optical band gap of the crystal were measured using UV±vis-NIR spectrum. The functional groups of the grown crystal were identified using FTIR spectrum. TGA-DTA and DSC studies reveal that the crystal LTSA is thermally stable up to 160 . The SHG efficiency of the grown is found to be nearly same as that of KDP. Therefore, it is concluded that the organo-metallic compound LTSA is a promising NLO material with enhanced SHG efficiency.

Reference

[1] S. Verma, M. K. Singh, V. K. Wadhawan , C. H. Suresh, Growth morphology of zinc tris (thiourea) sulphate crystals, Pramana ± J. Physics 54 (6) (2000) 879-888. [2] K. Sangwal, E. Mielniczek brzoska, Effect of impurities on metastable zone width for the growth of ammonium oxalate monohydrate crystals from aqueous solutions, J. Cryst. Growth 267 (2004) 662-675. [3] G. Li, L. Xue, G. Su, Z. Li, X. Zhuang, Y. He, Rapid growth of KDP crystal from aqueous solutions with additives and its optical studies, Cryst. Res. Technol 40 (2005) 867-870. [4] V. Sheelerani, J. Shanthi, International Journal of Engineering Research & Technology. 2 (2013) 2278-0181. [5] P.N. Prasad, D.J. Williams, Introduction to Nonlinear Optical Effects in Organic Molecules and Polymers, Wiley, New York, 1991. [6] D.F. Eaton, Science 253 (1991) 281. [7] D.S. Chemla, J. Zyss, Introduction to Nonlinear Optical Properties of Organic Molecules of Crystals, Academic Press, Orlando, 1987. [8] M.-H. Jiang, Q. Fang, Adv. Mater. 11 (1999) 1147. [9] J.B. Zeldovich, J. Exp. Therot. Phys. 12 (1942) 525; J. Frenkel, Kinetic Theory of Liquids, Dover, New York, 1955. [10] D. Turnbull, J.C. Fisher, J. Chem. Phys. 17 (1949) 71. [11] A.E. Nielson, O. Sohnel, Interfacial tensions in electrolyte crystal-aqueous solution from nucleation data J. Cryst. Growth 11 (1971) 233 ± 242.

[12] D.H.Rasmussen., M. R. Appleby, G. L. Leedom, S. V. Babu, Homogeneous Nucleation Kinetics J. Cryst.Growth 64 (1983) 229 - 238. [13] D.Jayaraman, C. Subramanian, P.Ramasamy, Kinetic process of homogeneous nucleation incorporating the effect of curvature J. Cryst. Growth 79 (1986) 997 - 1000. [14] D. Jayaraman , C.Subramanian , P.Ramasamy ,

Effect of curvature-dependent surface

tension on nucleation, J. Mater. Sci. Lett. 8 (1989) 1399 -1401. [15] Willium kemp, organic spectroscopy (2004) 258-263. [16] J .Tauc, Amorphous and liquid semiconductors, J. Tauc Ed.Plenum, Newyork, 1974. [17] B. Narayana Moolya, S.M. Dharmaprakash, J. Cryst. Growth 290 (2006) 498±503. [18] M. Thenmozhi, K. Suguna, C. Sekar, Spectrochimica Acta Part A 84 (2011) 37± 42. [19] J. Ramajothi, S. Dhanuskodi, J. Cryst. Growth 289 (2006) 217±223. [20] S.K. Kurtz, T.T. Perry, A powder technique for the evaluation of nonlinear optical materials, J. Appl. Phys. 39 (1968) 3798±3813.

Figure captions Fig.1 Photograph of the as-grown LPMC single crystal. Fig.2 A plot of ln

versus 1/(ln S)2.

Fig.3 Solubility curve of LTSA crystal. Fig.4 Plot of nucleation rate versus supersaturation. Fig.5 (a) Photograph of the crystal used for morphology study. (b) Morphology of LTSA crystal. Fig.6 UV±vis±NIR absorption spectrum of LTSA crystal. )LJ7DXF¶VSORWRI/76$FU\VWDO Fig.8 FTIR spectrum of LTSA crystal. Fig.9 TGA and DTA curves of LTSA crystal. Fig.10 DSC curve of LTSA crystal. Fig.11 1H NMR spectrum of LTSA crystal. Fig.12 SEM images of LTSA crystal. Fig.13 EDAX spectrum of LTSA crystal.

Table captions Table 1 Nucleation parameters of LTSA single crystal. Table 2 Compositional analysis of LTSA crystal from EDAX spectrum.

Fig.1 Photograph of as-grown LTSA crystal.

Fig. 2 A plot of ln

versus 1/(ln S)2.

Fig.3 Solubility curve of LTSA crystal.

Fig.4 Plot of nucleation rate versus supersaturation.

a Fig.5 (a) Photograph of the crystal used for morphology study.

.

b (b) Morphology of LTSA crystal.

Fig. 6 UV±vis±NIR absorption spectrum of LTSA crystal.

)LJ7DXF¶VSORWRI/76$FU\VWDO

Fig. 8 FTIR spectrum of LTSA crystal.

Fig.9 TGA and DTA curves of LTSA crystal.

Fig. 10 DSC curve of LTSA crystal.

Fig. 11 1H NMR spectrum of LTSA crystal.

a

b

Fig.12 SEM images of LTSA crystal.

c

Fig. 13 EDAX spectrum of LTSA crystal.

Table 1 Nucleation parameters of LTSA single crystal -ǻ*vx

r*

ǻ**

energy

107

(nm)

10-19J

ıo

J/m3

CNT

MCNT

CNT

MCNT

CNT

MCNT

1.07

2.78

4.47

4.42

5.23

4.89

123.2

115.1

1.075

2.97

4.19

4.13

4.58

4.25

107.8

100.2

1.08

3.16

3.93

3.88

4.04

3.74

95.3

88.1

1.085

3.35

3.71

3.66

3.60

3.31

84.7

77.9

1.09

3.54

3.51

3.46

3.22

2.95

75.9

69.5

Temper

Surface

ature (K)

S

ǻG*/kT

mJ/m2

308

6.2385

Table 2 Compositional analysis of LTSA crystal from EDAX spectrum.

Element

Wt%

At%

C

63.09

68.79

O

27.86

22.81

N

8.87

8.29

Na

0.19

0.11

GRAPHICAL ABSTRACT

1

H NMR spectrum of LTSA crystal

HIGHLIGHTS x

Nucleation kinetics of LTSA was studied to optimize the growth conditions.

x

FTIR, UV, NMR spectra of L-tyrosine sodium acetate were recorded and analysed.

x

Morphology and microstructure of the grown crystal were analysed.

x

The presence of sodium in LTSA was confirmed from EDAX analysis.

x

SHG efficiency of LTSA was found to be nearly same that as that of KDP.