Growth of New, Optically Active, Semi-Organic Single Crystals Glycine-Copper Sulphate Doped by Silver Nanoparticles

: The purpose of this study is to modify all physicochemical properties of glycine–copper sulphate single crystals, such as crystal habits, molar mass, thermal stability, optical activity, and electrical properties. The novelty of this study is growth of glycine–copper sulphate single crystals doped by a low concentration of silver nanoparticles (SNPs) that improved both crystal habits and physicochemical properties. The originality of this work is that trace amounts of SNPs largely increased the crystal size. Crystals have molar stoichiometric formula [glycine] 0.95 , [CuSO 4 · 5H 2 O] 0.05 in the absence and presence of silver nanoparticles (SNPs) in different concentrations: 10 ppm, 20 ppm, and 30 ppm. The crystals’ names and abbreviations are: glycine–copper sulphate (GCS), glycine– copper sulphate doped by 10 ppm SNPs (GCSN1), glycine–copper sulphate doped by 20 ppm SNPs (GCSN2), and glycine–copper sulphate doped by 30 ppm SNPs (GCSN3). Dopant silver nanoparticles increased: crystallinity reﬂecting purity, transparency to UV-Vis. electromagnetic radiation, thermal stability, and melting point of glycine–copper sulphate single crystal. GCSN3 is a super conductor. High thermal conductivity of crystals ranging from 1.1 W · min − 1 · K − 1 to 1.6 W · min − 1 · K − 1 enabled attenuation of electromagnetic radiation and rapid heat dissipation due to good dielectric and polar properties. On rising temperature, AC electrical conductivity and dielectric properties of perfect crystal GCSN3 increased conﬁrmed attenuation of thermal infrared radiation.


Introduction
Good optical, dielectric, and thermal properties of semi-organic single crystals enable application in modern technologies for design components in photonic devices, optical communication systems, optoelectronics, frequency convertors, and nonlinear optical (NLO) devices [1]. Single crystals of glycine amino acid containing copper sulphate (CuSO 4 ) are used in optical high-resolution band pass filters for spectral devices [2]. Such crystals having a good optical quality are rarely reported. At room temperature, glycine amino acid in zwitterion form is crystalized to α, β, and γ polymorphs [3][4][5]. Glycine-copper sulphate single crystals possess NLO activity and thermal stability due to synergism of both organic and inorganic components [6,7]. Glycine has a chiral center that crystallizes in non-centrosymmetric space groups [8]. Inorganic copper sulphate enhanced mechanical and thermal stability of glycine crystals [9]. Crystals' growth in the presence of doping impurities modified crystal habit and properties [10,11]. No studies are reported doping glycine-copper sulphate crystals by silver nanoparticles that is widely used in food, medical, industrial, catalysis, and pharmaceutical applications [12,13]. This study aims to grow new single crystals of glycine-copper sulphate in the absence and presence of silver nanoparticles to add new unique properties for these blue-colored glycine-copper sulphate

Materials and Methods
All chemicals in this study are highly pure, of analytical grade, and used as received without further purification: glycine (C 2 H 5 NO 2 , Oxford Co.) purity 98.5%, CuSO 4 ·5H 2 O (Sigma Aldrich Co., St. Louis, MO, USA), purity 98%. SNPs with polyvinylpyrrolidone, purity 99.9%, was purchased from Sigma Aldrich Co. with these physical characteristics: spherical shape nanoparticles: average diameter 21.44 ± 4.92 nm and UV: electronic absorption bands at maximum wavelength (λ max. 430 nm) due to delocalized electronic surface plasmon.
Slow solvent evaporation method is employed at 25 • C for growth of GCS crystals doped by SNPs. The stoichiometric formula is (glycine) 0.95 , [CuSO 4 ] 0.05 . Salts are dissolved in double distilled water and agitated at 50 rpm using a magnetic stirrer for two h to obtain a homogeneous saturated solution. For SNP doping, a solution of glycine and CuSO 4 are agitated at 50 rpm for two hours. Different concentrations of 10 ppm, 20 ppm, and 30 ppm SNPs are added to the filtrate that is further stirred for half an hour to complete homogeneity. The solution is covered by porous aluminum foil in a dust-free environment to allow slow solvent evaporation. High-quality, blue-color, pure crystals are harvested after one month, Figure 1. GCS crystals increased in size and intensity of blue color as doping concentration of SNPs increased.

Characterization of Single Crystals
The grown crystals are characterized by: Mass spectra (MS) by electron ionization technique at 70 eV using Thermo GCMS-ISQLT mass spectrometer; elemental analysis by energy dispersive X-ray analysis (EDX), and scanning electron microscope (SEM) using JSM-IT200 SEM.
Powder X-ray diffraction pXRD patterns at 25 • C and diffraction, reflection angle (2-theta) ranges from 5 • to 70 • at 0.02 • step and scan rate 1 • min −1 using Cu-Kα radiation of wavelength 1.5418 Å and acceleration voltage 40 kV using Bruker D8 advance diffractometer. Intensity of reflected X-rays in arbitrary units is plotted versus incidence and reflection angles 2θ • , FTIR vibrational spectra at the frequency range 400-4000 cm −1 using IR Prestige-21, Borken, Germany. UV-Vis. electronic absorption spectra using Helios alpha Unicom UV-Spectrophotometer at wavelength range 190-1200 nm; differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and differential thermal gravimetric (DTG) analysis at temperature range: 25-800 • C using SDT Q600 V20.9 Build 20 instrument, 20 • C·min −1 heating rate in de-aerated alumina cell to avoid sample oxidation by atmospheric oxygen; X-band electron spin resonance spectra ESR at room temperature, 9.43 GHz using reflection JES-RE1X ESR spectrometer in cylindrical resonance cavity with 100 kHz modulation, 5 mW power where applied magnetic field is controlled with LMR Gauss meter; electrical conductivity and dielectric characteristics of GCSN3 sample is measured using four probes Agilent 4294 A impedance bridge with sinusoidal voltage signal 10 mV amplitude. The sample is compressed as a pellet: 0.5 cm radius, 0.23 × 10 −2 m thickness, and 7.854 × 10 −5 m 2 geometrical area, coated on two opposite surfaces by silver paste for Ohmic contact with copper electrodes and annealed at 120 • C; thermal conductivity is measured at room temperature using hot disk TP 2500 [14].

Results and Discussion
MS is in Supplementary Information (SI); Figure S1 showed the relative abundance of the fragmented molecular ion versus EDX spectra and SEM micrographs: Figure 2a-d show SEM-EDX analysis of GCS, GCSN1, GCSN2, and GCSN3 crystals, respectively. These spectra were produced as a focused electron beam on the sample ejected electrons from the inner-most electron atoms in the crystal leaving holes filled by ejected electrons from higher level emissions of X-ray [14,15].
EDX spectra confirmed that SNPs improved self-assembly of GCS from Figure 2a-d. Perfect crystallization is attained in Figure 2d.
The data in Table 1 indicated that oxygen, carbon, and nitrogen have maximum weight %, confirming that glycine is the base matrix of these single crystals. EDX spectrums of the doped crystals confirm the entry of both Cu(II) ion and Ag(I) ions into glycine crystal lattice.
The The vibrational band in FTIR spectra, as shown in Figure S2, is assigned to the function groups in the crystals, Table 2.
UV-Vis. electronic absorption spectra using Helios alpha Unicom UV-Spectrophotometer at wavelength range 190-1200 nm; differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and differential thermal gravimetric (DTG) analysis at temperature range: 25-800 °C using SDT Q600 V20.9 Build 20 instrument, 20 °C.min −1 heating rate in de-aerated alumina cell to avoid sample oxidation by atmospheric oxygen; X-band electron spin resonance spectra ESR at room temperature, 9.43 GHz using reflection JES-RE1X ESR spectrometer in cylindrical resonance cavity with 100 kHz modulation, 5 mW power where applied magnetic field is controlled with LMR Gauss meter; electrical conductivity and dielectric characteristics of GCSN3 sample is measured using four probes Agilent 4294 A impedance bridge with sinusoidal voltage signal 10 mV amplitude. The sample is compressed as a pellet: 0.5 cm radius, 0.23 × 10 −2 m thickness, and 7.854 × 10 −5 m 2 geometrical area, coated on two opposite surfaces by silver paste for Ohmic contact with copper electrodes and annealed at 120 °C; thermal conductivity is measured at room temperature using hot disk TP 2500 [14].

Results and Discussion
MS is in Supplementary Information (SI); Figure S1 showed the relative abundance of the fragmented molecular ion versus , and GCSN3 crystals, respectively. These spectra were produced as a focused electron beam on the sample ejected electrons from the inner-most electron atoms in the crystal leaving holes filled by ejected electrons from higher level emissions of X-ray [14,15].
(a) EDX spectra confirmed that SNPs improved self-assembly of GCS from Figure 2a-d. Perfect crystallization is attained in Figure 2d.
The data in Table 1 indicated that oxygen, carbon, and nitrogen have maximum weight %, confirming that glycine is the base matrix of these single crystals. EDX spectrums of the doped crystals confirm the entry of both Cu(II) ion and Ag(I) ions into glycine crystal lattice.   IR spectra of the GCS crystal showed a strong vibrational band at 509.21 cm −1 due to Cu-N stretching [16], NH stretching band at 3811.34 cm −1 , And medium peak at 1111.00 cm −1 for CH 2 rocking [17]. There is a strong peak at 1334.79 cm −1 due to CH 2 wagging. Intense peak C=O asymmetric stretching occurs at 1604.77 cm −1 [18], symmetric stretching COOat 1411.68 cm −1 , intense band asymmetric stretching COOat 1519.91 cm −1 [19], and medium peak at 1033.85 cm −1 for CCN asymmetric stretching deformation [20]. There is strong band SO 4 − stretching at 894.97 cm −1 , an intense band due to bending COO − at 694.37 cm −1 , medium peak wagging COO − at 609.51 cm −1 [13], and NH 2 asymmetric stretching at 2823.79 cm −1 [21]. FTIR spectra of the samples GCSN1, GCSN2, and GCSN3 have small shift compared to that of GCS observed, which suggests the incorporation of SNPs into the crystals lattice.  Figure 3a-d showed indexed pXRD profile versus Rietveld refined PXRD patterns for GCS, GCSN1, GCSN2, and GCSN3 crystals. All pXRD patterns showed a prominent sharp diffraction peak at 30 • . SNPs increased the peaks' intensity and modified crystal structure and lattice planes [22][23][24]. The crystals' structure and geometry agreed with Crystallography Opened Database, COD files. GCS and GCSN1 have monoclinic unit cell alpha glycine. Triclinic GCSN2 and GCSN3 have gamma glycine. pXRD patterns are refined using Full prof Suit software using CIF files containing crystal information. Peak patterns are refined following pseudo-Voigt profile analytical function [25]. Background and peak shapes are modeled with linear fitting by applying least-squares cycles and six background (polynomial 6th grade parameters) at the wavelength of Cu-detector and neglecting instrument contribution [26]. The crystallinity followed the trend: Doping GCS with SNPs improved crystallinity, hence purity and crystal engineering. During refinement, the number and order of crystalline planes and diffraction peaks increased in the same order. Many iteration cycles and all noise data are neglected; too long iteration time is consumed for GCSN2 and GCSN3 due to extra high crystallinity, long cartesian coordinates, and different angles in the triclinic unit cell. Intense peaks shifted to lower 2-theta, indicating a pillared crystal structure. Small peak absence and no polycrystallinity regions are observed in the perfect GCSN3 crystal, which confirmed good surface. There is good fitting of pXRD spectra (calculated intensity of the diffraction peaks are close to each other, resulting in a very negligible difference between the observed and calculated intensities (Yobs.-Ycal.)) with less than zero in arbitrary unit.
Both observed and calculated profiles are closely coincided to each other in a nonlinearly fit. Sharp intense pXRD patterns with a dominating diffraction peak in crystals confirmed good crystallinity. Intensity changes and a slight shift in peak positions of GCS by SNPs reflected modified crystalline planes [23]. Diffraction peaks at 44.4 • and 64.7 • in GCSN2 and GCSN3 confirmed doping impurities [24].
Miller indices h k of the crystal planes, full width at half maximum (FWHM) of XRD patterns, peak position, and inter planar distance (d cal .), are collected in Table S1. The crystallinity and geometry of single crystals are deduced from pXRD by matching these diffraction patterns to pdf cards of similar crystals in Crystallography Opened Database using FWHM that characterized different material properties and surface integrity features [25,26]. The unit cell parameters are collected in Table 3.
Appl. Nano 2023, 4, FOR PEER REVIEW 6 shifted to lower 2-theta, indicating a pillared crystal structure. Small peak absence and no polycrystallinity regions are observed in the perfect GCSN3 crystal, which confirmed good surface. There is good fitting of pXRD spectra (calculated intensity of the diffraction peaks are close to each other, resulting in a very negligible difference between the observed and calculated intensities (Yobs.-Ycal.)) with less than zero in arbitrary unit. Both observed and calculated profiles are closely coincided to each other in a nonlinearly fit.  Sharp intense pXRD patterns with a dominating diffraction peak in crystals confirmed good crystallinity. Intensity changes and a slight shift in peak positions of GCS by SNPs reflected modified crystalline planes [23]. Diffraction peaks at 44.4° and 64.7° in GCSN2 and GCSN3 confirmed doping impurities [24].
Miller indices h k ℓ of the crystal planes, full width at half maximum (FWHM) of XRD patterns, peak position, and inter planar distance (dcal.), are collected in Table S1. The crystallinity and geometry of single crystals are deduced from pXRD by matching these diffraction patterns to pdf cards of similar crystals in Crystallography Opened Database using FWHM that characterized different material properties and surface integrity fea- UV-Vis. absorbance spectrum of crystals at wavelength range 190-1100 nm are shown in Figure 4. UV-Vis. absorbance curve showed cut-off of wavelength λ cut off is lower than that of glycine [27].  UV-Vis. absorbance spectrum of crystals at wavelength range 190-1100 nm are shown in Figure 4. UV-Vis. absorbance curve showed cut-off of wavelength λcut off is lower than that of glycine [27]. Doping by SNPs decreased λcut off, i.e., increased band gas for UV-electronic transition. SNPs enhanced transparency of crystals to UV radiation-enabled deposition as thin film on glass for protection against UV radiation [28,29]: Band gap-controlled UV absorption coefficient depends on the energy of the incident photon and is estimated using Equation (2) [30,31]. ℎ = (ℎ − Eg ) (2) where ν frequency of the incident radiation is inversely proportional to the wavelength of absorbance (λ), A is constant, and the exponent r depends on the nature of electronic transition. r = 2 for indirect transition, and r = ½ for allowed direct transition, r = ½. Since all  Doping by SNPs decreased λ cut off , i.e., increased band gas for UV-electronic transition. SNPs enhanced transparency of crystals to UV radiation-enabled deposition as thin film on glass for protection against UV radiation [28,29]: Band gap-controlled UV absorption coefficient depends on the energy of the incident photon and is estimated using Equation (2) [30,31].
where ν frequency of the incident radiation is inversely proportional to the wavelength of absorbance (λ), A is constant, and the exponent r depends on the nature of electronic transition. r = 2 for indirect transition, and r = 1 2 for allowed direct transition, r = 1 2 . Since all crystals are blue colored, allowed direct transition is considered [15,30]. The optical gaps, Eg, are calculated from plots (αhν) 2 as a function of photon energy (hν), as shown in Figure 5, and the observed values Eg are given in Table 4 along with the values of all reported glycine single crystals.
Appl. Nano 2023, 4, FOR PEER REVIEW 11 crystals are blue colored, allowed direct transition is considered [15,30]. The optical gaps, Eg, are calculated from plots (αhν) 2 as a function of photon energy (hν), as shown in Figure 5, and the observed values Eg are given in Table 4 along with the values of all reported glycine single crystals.  λcut off 287 nm for GCS decreased to 283, 276, and 280 nm for GCSN1, GCSN2, and GCSN3, respectively, which indicated an increasing band gap. Blue shift of λcutoff to lower values indicated SNPs' improved polarizability of electron density on the single crystals. This finding suggested the suitability of GCS-doped SNPs single crystals for applications in optoelectronic devices such as frequency multiplier, sum-, difference-, and blue laser frequency generators, etc. [34]. Optical band gaps' eV are 4.58, 4.61, 4.65, and 4.67 for GCS, GCSN1, GCSN2, and GCSN3 crystals, respectively. SNPs increased Eg and enhanced optical properties of GCS. High Eg indicated the decrease in the localized energy states on doping by SNPs due to extrinsic defects or disorders in GCS caused by interstitial doped SNPs [35].  λ cut off 287 nm for GCS decreased to 283, 276, and 280 nm for GCSN1, GCSN2, and GCSN3, respectively, which indicated an increasing band gap. Blue shift of λ cut off to lower values indicated SNPs' improved polarizability of electron density on the single crystals. This finding suggested the suitability of GCS-doped SNPs single crystals for applications in optoelectronic devices such as frequency multiplier, sum-, difference-, and blue laser frequency generators, etc. [34]. Optical band gaps' eV are 4.58, 4.61, 4.65, and 4.67 for GCS, GCSN1, GCSN2, and GCSN3 crystals, respectively. SNPs increased Eg and enhanced optical properties of GCS. High Eg indicated the decrease in the localized energy states on doping by SNPs due to extrinsic defects or disorders in GCS caused by interstitial doped SNPs [35].
Good optical properties of the GCS crystals doped by SNPs are confirmed by extinction coefficient K calculated using Equation (3); α and refractive index (n) reflect dissipated incident radiation by absorption and scattering [36,37].
Positive refractive index (n) 1.6-1.8 indicated dispersion of incident radiation on the crystals is inversely proportional to the photon energy. Refractive index (n) is decreased by increasing photon energy and concentration of SNPs. High photon energy enables passing through the crystal lattice with low dispersion. SNPs decreased dispersion of incident radiation by improving transparency to UV radiation. High transmission and low absorbance of UV radiation and low refractive index suggest the single crystals are suitable for antireflection coating in solar thermal devices and NLO applications [38].
Positive refractive index (n) 1.6-1.8 indicated dispersion of incident radiation on the crystals is inversely proportional to the photon energy. Refractive index (n) is decreased by increasing photon energy and concentration of SNPs. High photon energy enables passing through the crystal lattice with low dispersion. SNPs decreased dispersion of incident radiation by improving transparency to UV radiation. High transmission and low absorbance of UV radiation and low refractive index suggest the single crystals are suitable for antireflection coating in solar thermal devices and NLO applications [38].    GSC crystals showed large noise scattering in electrical susceptibility. This scattering disappeared on doping by SNPs that elevated electrical susceptibility (χ) at high photon energy following the order: GCSN2 > GCSN3 > GCSN1>>> GCS GCSN3 showed lower χ than GCSN2 due to extra high crystallinity; GCSN3 decreased the mean free path for electron charge transfer.
The calculated electric susceptibility is plotted with photon energy; Figure 7 shows electric susceptibility (χ) is about 0.25 for all crystals at low photon energy.
where parameters a and b are calculated from intercept (a) and slope b of straight-line Cp-T plot. Cp of all prepared single crystals showed nonlinear variation with the absolute temperature, Figures S4-S7.
Thermal lattice coefficient α and electronic heat capacities γ are obtained from linear C p T versus T 2 plot, (coefficient, R 2 above 0.99) Figures S4a,b and S7a,b. Table 5 shows linear fits parameters of DCS.  The calculated electric susceptibility is plotted with photon energy; Figure 7 shows electric susceptibility (χ) is about 0.25 for all crystals at low photon energy.
where parameters a and b are calculated from intercept (a) and slope b of straight-line Cp-T plot. Cp of all prepared single crystals showed nonlinear variation with the absolute temperature, Figures S4-S7. Thermal lattice coefficient α and electronic heat capacities γ are obtained from linear C p T versus T 2 plot, (coefficient, R 2 above 0.99) Figures S4a,b and S7a,b. Table 5 shows linear fits parameters of DCS.
Heat capacity at constant pressure, Cp, is the heat required to raise the temperature of the crystal sample by 1 • C and represents the variation of the heat content of the crystal sample on heating. The variation of α, γ coefficients approved Cp variation with temperature. This finding indicated that the Cp amount of thermal heat absorbed by the crystals increases on heating, enabling the application of a heat shielding coating on thin film glasses.
ESR spectra of powder sample crystals are shown in Figure 9. Anisotropy g-factor for crystals confirmed low symmetry. Spin Hamiltonian parameters g and A tensors revealed rhombic symmetry crystal field around Cu(II) ion split ground state. Degeneracy of ground state energy level is lifted giving static Jahn-Teller distortion [48,49].
R = (g x − g y )/(g z − g x ) (8) Table 6 includes g factor, hyper fine constants A, and R for the crystals. Values A and g factor have no axial symmetry in the crystal lattice (no dynamic Jahn-Teller) [52]. R = 0.1805, 0.1224, 0.1673, 0.1418 for GCS, GCSN1, GCSN2, and GCSN3, respectively; less than unity indicated d x 2 −y 2 ground state for unpaired electron [53]. A x , A y equals A are lower than A z; g-parallel is greater than perpendicular g ⊥ and confirmed d x 2 −y 2 ground state [52]. g value is less than 2.3, indicating strong covalent copper-glycine bond [54].
Ax, Ay equals A ∥ are lower than Az; g-parallel is greater than perpendicular g⏊ and confirmed dx 2 -y 2 ground state [52]. g ∥ value is less than 2.3, indicating strong covalent copper-glycine bond [54].   Figure 10 showed UV of thin film coating of GCSN3 on the aluminum (Al) foil sample. An aqueous solution of GCSN3 was evaporated under ultra-high vacuum conditions onto the Al foil where carboxylate COOH of glycine zwitterion amino acid is chemically adsorbed on the aluminum surface. Absorption at long λ 900-1100 nm for this crystal near Appl. Nano 2023, 4 132 IR region indicates absorption of thermal energy of IR radiation. Phonon bands at 900 nm originate from vibrational modes of harmonic and unharmonic oscillators in the crystal lattice. Absorbed IR radiation causes thermal vibrations of atoms or molecules and creates thermal phonon waves that propagate in the crystal lattice, dissipating thermal IR energy.
glycine ligand [56]. SNPs decreased covalence parameter (α 2 ) of glycine-Cu(II) bond, except that GCSN2 showed abnormally high α 2 , which confirmed its highest electrical susceptibility. Figure 10 showed UV of thin film coating of GCSN3 on the aluminum (Al) foil sample. An aqueous solution of GCSN3 was evaporated under ultra-high vacuum conditions onto the Al foil where carboxylate COOH of glycine zwitterion amino acid is chemically adsorbed on the aluminum surface. Absorption at long λ 900-1100 nm for this crystal near IR region indicates absorption of thermal energy of IR radiation. Phonon bands at 900 nm originate from vibrational modes of harmonic and unharmonic oscillators in the crystal lattice. Absorbed IR radiation causes thermal vibrations of atoms or molecules and creates thermal phonon waves that propagate in the crystal lattice, dissipating thermal IR energy. Absorptivity of GCSN3 near the IR region of electromagnetic radiation indicated that crystals can shield thermal heat of IR radiation on the coating as dispersed thin film on alumetal.
The sun provides thousands W.m −2 energy on the earth's surface daily. Total solar energy in the upper atmosphere contains 50% IR radiation, 40% Vis. Light, and 10% UV radiation. IR radiation causes vibrations that heats earth's surface [57]. Attenuation of thermal energy can be achieved by painting glass windows with these blue color crystals transparent to UV radiation, filtering, and that dissipates IR radiation. Absorptivity of GCSN3 near the IR region of electromagnetic radiation indicated that crystals can shield thermal heat of IR radiation on the coating as dispersed thin film on alumetal.
The sun provides thousands W·m −2 energy on the earth's surface daily. Total solar energy in the upper atmosphere contains 50% IR radiation, 40% Vis. Light, and 10% UV radiation. IR radiation causes vibrations that heats earth's surface [57]. Attenuation of thermal energy can be achieved by painting glass windows with these blue color crystals transparent to UV radiation, filtering, and that dissipates IR radiation.
High thermal conductivity of crystals equals: 1.10, 1.21, 1.54, and 1.6 W·m −1 K −1 for GCS, GCSN1, GCSN2, and GCSN3 confirmed rapid attenuation of many incident EM waves by dielectric components and rapidly dissipated as heat. Figure 11 showed electrical conductivity of GCSN3 increased on heating as a typical semiconductor behavior due to thermally activated charge carriers' mobility [58].
Impedance plots confirmed super conductivity. A plateau region at low 0.1Hz frequency region represents total conductivity of grain boundary. A high-frequency region at 100 kHz represents the contribution of grains to total conductivity. An intermediate frequency region at 1 kHz is due to charges trapped between grain boundaries and grains [15]. AC conductivity confirmed the dielectric nature of a single crystal can dissipate heat rapidly. The high-frequency dielectric constant is 4.49.
Dielectric study of GCSN3 crystal response of charges to applied electric field showed dielectric constants at 100 Hz, 1 kHz, 10 kHz, and 100 kHz and a temperature range of 200-550 K. Dielectric constant was calculated using equation [59]: where ε o is free space permittivity, C and d are capacitance and thickness of pellet, and A is electrode area.
High thermal conductivity of crystals equals: 1.10, 1.21, 1.54, and 1.6 W.m −1 K −1 for GCS, GCSN1, GCSN2, and GCSN3 confirmed rapid attenuation of many incident EM waves by dielectric components and rapidly dissipated as heat. Figure 11 showed electrical conductivity of GCSN3 increased on heating as a typical semiconductor behavior due to thermally activated charge carriers' mobility [58].   Impedance plots confirmed super conductivity. A plateau region at low 0.1Hz frequency region represents total conductivity of grain boundary. A high-frequency region at 100 kHz represents the contribution of grains to total conductivity. An intermediate frequency region at 1 kHz is due to charges trapped between grain boundaries and grains [15]. AC conductivity confirmed the dielectric nature of a single crystal can dissipate heat rapidly. The high-frequency dielectric constant is 4.49.
Dielectric study of GCSN3 crystal response of charges to applied electric field showed dielectric constants at 100 Hz, 1 kHz, 10 kHz, and 100 kHz and a temperature range of 200-550 K. Dielectric constant was calculated using equation [59]:   Figure 11 showed electrical conductivity of GCSN3 increased on heati semiconductor behavior due to thermally activated charge carriers' mobilit   Impedance plots confirmed super conductivity. A plateau region at l quency region represents total conductivity of grain boundary. A high-fre at 100 kHz represents the contribution of grains to total conductivity. An frequency region at 1 kHz is due to charges trapped between grain boundar [15]. AC conductivity confirmed the dielectric nature of a single crystal can rapidly. The high-frequency dielectric constant is 4.49.
Dielectric study of GCSN3 crystal response of charges to applied electri dielectric constants at 100 Hz, 1 kHz, 10 kHz, and 100 kHz and a temperature 550 K. Dielectric constant was calculated using equation [59]: Real ε and imaginary ε" components of ε represented equals [60]: Figure 13 showed ε varied with temperature at a different frequency and decreased with increasing frequency, indicating an ability to dissipate incident IR radiation. ε decreased until it reached glass transition Tg at 380 K, then became limited up to 470 K. Peak at Curie TC represented phase transition from ferroelectric to paraelectric behavior.
Real ε′ and imaginary ε″ components of ε represented equals [60]: ε′=|ε|cosθ, ε″=|ε|sinθ (12) Figure 13 showed ε′ varied with temperature at a different frequency and decreased with increasing frequency, indicating an ability to dissipate incident IR radiation. ε′ decreased until it reached glass transition Tg at 380 K, then became limited up to 470 K. Peak at Curie TC represented phase transition from ferroelectric to paraelectric behavior.

Conclusions
SNPs dopant increased thermal stability of gamma and alpha glycine single crystals. Optical absorption studies revealed that cut-off wavelengths are 287, 283, 276, and 280 nm and optical band gap energy 4.58, 4.61, 4.65, and 4.67 eV for GCS, GCSN1, GCSN2, and GCSN3 single crystals, respectively. SNPs increased band gaps of crystals, hence transparency to UV radiation. AC electrical conductivity of the thin film sample of perfect crystal increased to 0.03 Siemens/cm. High thermal conductivity, W.m −1 K −1 in range 1.10-1.6, confirmed efficient radiation attenuation by rapid heat dissipation due to dielectric properties of single crystals. Single crystals could be used to shield and dissipate thermal heat of IR radiation. AC confirmed the dielectric component and increased on heating due to thermal activation of charge carriers.

Conclusions
SNPs dopant increased thermal stability of gamma and alpha glycine single crystals. Optical absorption studies revealed that cut-off wavelengths are 287, 283, 276, and 280 nm and optical band gap energy 4.58, 4.61, 4.65, and 4.67 eV for GCS, GCSN1, GCSN2, and GCSN3 single crystals, respectively. SNPs increased band gaps of crystals, hence transparency to UV radiation. AC electrical conductivity of the thin film sample of perfect crystal increased to 0.03 Siemens/cm. High thermal conductivity, W·m −1 K −1 in range 1.10-1.6, confirmed efficient radiation attenuation by rapid heat dissipation due to dielectric properties of single crystals. Single crystals could be used to shield and dissipate thermal heat of IR radiation. AC confirmed the dielectric component and increased on heating due to thermal activation of charge carriers.