9-ACT Final Report (PDF) - AQA

SHRI DHARMASTHALA MANJUNATHESHWARA COLLEGE (AUTONOMUS) Ujire-574240 Re-Accredited by NAAC with “A++” Grade Department of Postgraduate Studies and Research in Physics (Affiliated to Mangalore University) A...

SHRI DHARMASTHALA MANJUNATHESHWARA COLLEGE (AUTONOMUS) Ujire-574240 Re-Accredited by NAAC with “A++” Grade Department of Postgraduate Studies and Research in Physics (Affiliated to Mangalore University) A Project Report on “ STRUCTURAL AND NON-LINEAR OPTICAL INVESTIGATION ON A CENTROSYMMETRIC ORGANIC CHALCONE” Submitted for the partial fulfilment for the Award of Degree in Master of Science in Physics Submitted by Ms. Deepika P R (P05SY22S103042) Ms. Prakrathi (P05SY22S103040) Ms. Sushmitha B (P05SY22S103045) Ms. Kaveri N P (P05SY22S103044) Ms. Mandara S B (P05SY22S103050) Under the Guidance of Dr. D. Haleshappa Assistant Professor Department of Post Graduate Studies and Research in Physics July-2024 SHRI DHARMASTHALA MANJUNATHESHWARA COLLEGE (AUTONOMOUS) Ujire-574240 Re-Accredited by NAAC with” A” Grade (CGPA 3.61 out of 4) DAKSHINA KANNADA, KARNATAKA STATE Ph: 08256-236101(0), Fax: 236220, 237601 E-Mail: sdmcollege@redi_mail.com, [email protected] Website: www.sdmcujire.in Date: CERTIFICATE This is to certify that the project titled “STRUCTURAL AND NON-LINEAR OPTICAL INVESTIGATION ON A CENTROSYMMETRIC ORGANIC CHALCONE” is a bonafide work carried out by Ms. Deepika, Ms. Prakrathi, Ms. Sushmitha, Ms. Kaveri, Ms. Mandara, for the partial fulfilment for the award of degree in Master of Science in Physics of Shri Dharmasthala Manjunatheshwara College (Autonomous), Ujire, during 2023-24. Principal H.O.D Dr. B. A. Kumara Hegde Dr. Raghavendra S  DECLARATION We hereby declare that the project, titled “ STRUCTURAL AND NON-LINEAR OPTICAL INVESTIGATION ON A CENTROSYMMETRIC ORGANIC CHALCONE” has been conducted by us under the valuable guidance of Dr. D. Haleshappa, Asst.Professor, Department of PG Studies and Research in Physics, Shri Dharmasthala Manjunatheshwara College (Autonomous), Ujire. The report is being submitted for the partial fulfilment of Master of Science degree in Physics, of Shri Dharmasthala Manjunatheshwara College (Autonomous), Ujire. We also declare that this project topic of our study has not been previously studied or formed the basis for the award of any Degree/ Associateship/ Fellowship or similar title in this college or in other university. Ms.Deepika P R Place: Ujire Ms. Prakrathi Date: Ms.Sushmitha B Ms. Kaveri N R Ms. Mandara S B Department of PG studies and Research in Physics, SDM College (Autonomous), Ujire  GUIDE CERTIFICATE This is to certify that the project work entitled “ STRUCTURAL AND NON-LINEAR OPTICAL INVESTIGATION ON A CENTROSYMMETRIC ORGANIC CHALCONE” is a bonafide work carried out by Ms. Deepika P R (P05SY22S103042), Ms. Prakrathi (P05SY22S103040), Ms. Sushmitha B (P05SY22S103045), Ms. Kaveri N P (P05SY22S103044), Ms. Mandara S B (P05SY22S1030450) of M.Sc. Physics, under my guidance and submitted to Department of PG Studies and Research in Physics, Shri Dharmasthala Manjunatheshwara College (Autonomous), Ujire, during the year 2023-24 for partial fulfilment of requirement for the award of Master of Science degree in Physics and it has not formed the basis for the award previously of any Degree/ Associateship/ Diploma/ Fellowship or any other similar titles. Place: Ujire Signature Date: (Dr. D. Haleshappa) Department of PG studies and Research in Physics, SDM College (Autonomous), Ujire  ACKNOWLEDGEMENT We express our profound and sincere gratitude to Dr. D Veerendra Heggade, President of Shri Dharmasthala Manjunatheshwara Educational Trust, for giving us an opportunity to do this project work. We would like to record our gratitude to Dr. Sateeshchandra S, Secretary of Shri Dharmasthala Manjunatheshwara Educational Trust, for giving us an opportunity to do this project work. We express our profound and sincere thanks to Dr. B. A. Kumara Hegde Principal of Shri Dharmasthala Manjunatheshwara College (Autonomous) Ujire, for extending all facilities to complete this project work. We express our profound and sincere thanks to Dr.P. Vishwanatha, Dean, Post-Graduation Centre, Shri Dharmasthala Manjunatheshwara College (Autonomous) and Dr. Raghavendra S. Head of the Department of PG Studies and Research in Physics, Ujire, for giving us an opportunity to do this project work. We feel great pleasure in expressing our sincere thanks and heartfelt gratitude to our research Guide Dr. D. Haleshappa, Asst.Professor, for his valuable guidance, constant and timely Assistance and encouragement at all stages in completing this project. We would like to express our gratitude to Instrumentation Centre for Research supported by DST-FIST (SDM PG Centre, Ujire), SAIF IT MADRAS and Ms. Neelamma Gummagal, Asst. Professor, KLE University, Gokul Road, Hubli support in UV- Visible Spectroscopic analysis, FT-IR, Photoluminescence, TG-DSC, NLO. We would like to express our sense of gratitude to all faculty members and non-teaching staffs of Department of PG Studies and Research in Physics, Shri Dharmasthala Manjunatheshwara College (Autonomous), Ujire, for their continuous motivation. Department of PG studies and Research in Physics, SDM College (Autonomous), Ujire.  Abstract In the present work, five π-conjugated organic chalcone derivatives were synthesized using Claisen Schmidt condensation method. Among five derivatives, A thiophene based (2E)-3- (anthracen-9-yl)-1-(thiophen-2-yl) prop–2-en-1-one (9ACT) derivative was comprehensively characterized for their thermal and optical behavior along with structural characterizations. The single crystal XRD analysis confirms that 9ACT crystallizes with orthorhombic crystal system under centrosymmetric space group Pbca with the lattice parameters a = 14.43(6) Å, b =9.77(14) Å, c = 22.58(3) Å, 𝛼 = 𝛽 = 𝛾 = 900 and V=3185 Å3. The examined molecules contained electron-donor and electron-acceptor groups interacting via a π-conjugated bridge. The functional groups and material purity is confirmed by FT-IR spectroscopic technique. The crystal is subjected to thermal analysis using differential scanning calorimetric, and thermogravimetric measurements and is thermally stable up to 101.4 oC. The synthesized molecule was characterized by UV-Vis-NIR spectrometer. The photoluminescence spectrum reveals blue light emission property of 9ACT crystal. In the visible region, all the derivatives possess extensive optical transmission. Their two-photon absorption (2PA) properties were characterized by the open- and closed-aperture Z-scan technique. Under continuous wave laser (CW=532nm) the Z-scan experimental results of the 9ACT crystal reveals the strong nonlinear absorption coefficient (β= 4.5 × 10-5 cm/W) and negative nonlinear refractive index (n2 = -2.79×10-9 cm2/W) under continuous wave regime. The 9ACT crystal perfectly proficient the criteria of one photon (W > 1) and two-photon (T < 1) figures of merit with estimations W= 1.3 and T = 0.3 Hence, obviously the title compound has a vast scope in optoelectronic device applications. Nonlinear optical studies show that the 9ACT crystal is a promising source for applications in photonic and optical power limiting devices. Keywords: Z-Scan technique, Chalcone, Third order NLO, Optical limiting, Single Crystal XRD. i  TABLE OF CONTENTS CHAPTER NO. TITLE Page. No Abstract i Table of Contents ii List of Figures iii Abbreviations iv 1 Introduction 1-2 2 Research Problem Statement 3 3 Literature Review 4 4 Objectives of Project 5 5 Experimental Method 6 5.1 Synthesis and Crystal Growth 6-8 6 Result and Discussion 9-23 6.1 Structural details 9 6.2 Fluorescence 9-10 6.3 Vibrational Analysis 10-11 6.4 Thermal Analysis 11-12 6.5 UV-Visible Studies 13-18 6.6 Non-Linear optical studies 19-22 7 Conclusion 23 8 Scope for Further Research 24 9 References 25-27 ii  List of Figures Figure.no Title Page.no 1 Synthesis Scheme of 9ACT 6 2 Synthesis Scheme of 4BNB 7 3 Synthesis Scheme of 4EDB 8 4 Synthesis Scheme of 4EBD 8 5 Synthesis Scheme of 9ECA 8 6 The Ball and Structure of 9ACT 9 7 Fluorescence plot 10 8 FTIR Spectrum of 9ACT 11 9 TG/DSC/DTG curve 12 10 Absorption Spectra of 9ACT 14 11 Optical Band gap of 9ACT compound 14 12 Absorption Spectra of 4EBD 15 13 Optical Band gap of 4EBD compound 15 14 Absorption Spectra of 4EDB 16 15 Optical Band gap of 4EDB compound 16 16 Absorption Spectra of 4BNB 17 17 Optical Band gap of 4BNB compound 17 18 Absorption Spectra of 9ECA 18 19 Optical Band gap of 9ECA compound 18 20 Open Aperture curve of 9ACT 21 21 Close Aperture curve of 9ACT 22 22 Optical limiting plot of 9ACT 22 iii  ABBREVIATIONS 1 NLO –Nonlinear optical 2 9ACT – (2E)-3-(anthracene-9-yl)-1-(thiophene-2-yl)prop-2-en-1-one 3 TGA – Thermogravimetric analysis 4 DSC – Differential Scanning Calorimetry 5 FTIR – Fourier Transform Infrared Spectroscopy 6 SHG – Second harmonic generation 7 DMF – Dimethyl formamide 8 DTG – Differential Thermal Gravimetric 9 XRD - X- ray diffraction 10 UV - Ultraviolet Visible spectrum 11 NaOH – Sodium Hydroxide 12 CA – Closed Aperture 13 OA-Open aperture 14 NLA-Nonlinear absorption 15 OL-Optical limiting iv  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 1. Introduction The interaction between materials and intense electromagnetic fields from high power laser pulses modulates the parameters of the laser pulse itself, which is referred to as nonlinear optical effect. Materials possessing such nonlinear optical response can be exploited for the manipulation of optical signals in a variety of optical devices–. NLO materials possessing the required properties for specific applications continue to be a topic of research in spite of extensive investigations carried out in the past on a large variety of materials such as semiconductors, conjugated organic polymers, porphyrins, liquid crystals, dyes, fullerenes, nanocomposites, charge transfer complexes and organometallics–. The phenomenon of optical power limiting, a nonlinear optical effect, has attracted much attention due to its application to protection of eyes and sensitive optical devices from high power laser pulses. Since the discovery of optical limiting phenomenon, much work has been done in synthesizing new materials with adequate optical limiting property. An optical limiter strongly attenuates the laser pulses of high intensity where as it is completely transparent at lower light intensities. Ideally, the laser pulse energy transmitted through the limiter rises linearly with input energy and saturates to a constant value at high energies. The limiting threshold is defined as the input energy at which the transmittance is fifty percent. Above the threshold, the output energy is clamped to the saturated value which depends on the material. The origin of the nonlinear optical susceptibilities of organic compounds is not only electronic, but also ionic. Generally, optical limiting property exhibited by organic molecules is related to high delocalization of the pi-electrons. The optical limiting behavior resulting from nonlinear absorption can occur due to reverse saturation absorption, two photon absorption, nonlinear refraction and nonlinear scattering. Nonlinear optical property observed in some materials such as semiconductor can be explained on the basis of two photon absorption wherein the material absorbs two photons simultaneously at the higher light intensity. In general, the method adopted to improve the nonlinear optical properties is to synthesize organic compounds of the type, electron donor–bridge–electron acceptor/donor (D–π–A or D–π–D). The molecules in which donor and acceptor groups connected at the terminal 1  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” positions of a π bridge to create highly polarized molecules could exhibit large molecular nonlinearity. Organic optic materials have been an area of interest due to their non-linear optical properties and possible applications in optical computing, frequency mixing, Laser radar, electro optics and laser industry, optical data storage, remote sensing, optical communication and dynamic processing of images. Particularly organic non-linear optical materials are considered to be ideal materials for electronics and optical communication. Among the large varieties of materials evaluated, organic materials have attracted an attention due to their high nonlinear properties and ultrafast response. In specific Conjugated organic systems are more attractive since they have delocalized 𝜋 electrons, which causes for an excellent NLO properties as they can be easily polarized. Chalcone molecules are highly polarized due to the presence of donor and acceptor groups in aromatic rings. These are significant group of flavonoids present in naturally occurring plant species. Chalcones are three carbons α, β-unsaturated carbonyl group with two aromatic rings. These natural products and synthetic compounds are finding their application as potential antiviral, anticancer, antioxidant, antimalarial, antimicrobial, anti-inflammatory and antifungal agents. Also, these, β-unsaturated carbonyl system of chalcones are emerging as promising analogues for light-sensitive materials and third-order non-linear optical properties. Among many chalone families, the Thiophene is much more suitable than any other families such as a pyrrole, pyridine, and furan due to their strong push pull behavior via carbonyl chain. Fascinated by the possible applications of chalcones, we used the Claisen-Schmidt condensation method to synthesize eight variants. A derivative (2E) −3-(anthracen-9-yl) −1-(thiophen-2-yl) prop-2-en-1-one was comprehensively studied utilizing several characterisation techniques. 2  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 2. Research problem statement In the present scenario, the organic second and third- order nonlinear material are interesting over inorganic materials due to their distinct properties like high laser thresholds value, low absorption coefficient, ultra-fast response, and high nonlinearity and play a major role in photonic technology. The NLO behavior of organic molecules originates mainly from a strong donor-acceptor intermolecular interaction and demoralized (𝜋)-electron system. The (𝜋)-conjugated organic compounds have emerged as a promising class of third-order NLO material because of their potentially large third order susceptibilities associate with fast response time in addition to their process ability. In fact, these chalcone derivatives are D- (𝜋)-A, D-( 𝜋)-D and D-( 𝜋)-A-( 𝜋)-D (D-Donor, A-Acceptor) intermolecular charge transfer type molecules. Out of which, thiophene is one of the most extensively employed electron rich material for these system being their good environmental stability, highly reversible redox switching, semiconducting nature and NLO properties. Linear optical properties and third order non linearity in order to analyze whether they can be utilized in photonic applications. 3  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 3. Literature Review Thiophene and chalcone derivatives have gathered significant attention in the fields of medicinal chemistry and organic synthesis due to their diverse pharmacological properties and potential applications in drug discovery. This literature review aims to provide insights into the recent advancements and emerging trends in the synthesis and pharmacological activities of these compounds. Thiophene derivatives exhibit a wide range of pharmacological activities including anti- inflammatory, antimicrobial, antiviral, antitumor, and antioxidant, properties. Recent research has highlighted the potential of thiophene derivatives as promising candidates for the treatment of various diseases such as cancer, Alzheimer's disease, and infectious diseases. Structure-activity relationship (SAR) studies have played a crucial role in elucidating the structural requirements for enhancing the pharmacological activities of thiophene derivatives. Chalcone derivatives are commonly synthesized via Claisen-Schmidt condensation between aromatic aldehydes and ketones. Recent advancements in synthetic methodologies have focused on the development of novel strategies for the synthesis of chalcone derivatives including microwave-assisted synthesis, solvent-free synthesis, and multicomponent reactions. These methods offer several advantages including high yields, shorter reaction times, and environmental sustainability. Chalcone derivatives possess diverse pharmacological activities such as anticancer, anti- inflammatory, antioxidant, antimicrobial, and antiviral properties. Structural modification of the chalcone scaffold has led to the development of analogs with improved pharmacokinetic and pharmacodynamics profiles. Furthermore, hybrid molecules incorporating chalcone and other pharmacophores have emerged as promising candidates for the treatment of various diseases. Hence, thiophene and chalcone derivatives represent important classes of compounds with significant pharmacological potential,. The synthesis and pharmacological evaluation of these derivatives have paved the way for the discovery of novel drug candidates with improved therapeutic profiles. Further research focusing on the optimization of synthetic methodologies and elucidation of structure-activity relationships is essential for the development of next-generation therapeutics based on thiophene and chalcone frameworks. 4  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 4. Objectives of the Project The present work has been conducted on the following objectives a) To synthesize thiophene based chalcone derivatives using Claisen-Schmidt condensation reaction method. b) To grow the single crystals of synthesized compounds by the solution growth technique. c) To characterize the grown crystals using Photoluminescence, Ultraviolet – Visible Spectroscopic Studies (UV), Z–Scan analysis (NLO). d) Thermogravimetric – Differential Scanning Calorimetry (TG - DSC) and Fourier Transform Infrared Spectroscopic Studies (FTIR). 5  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 5. Experimental Method 5.1. Synthesis and Crystal growth All the compounds of novel chalcone derivatives were prepared using Claisen–Schimidt condensation reaction method. The synthesis product was obtained by stirring the aldehydes and ketones with a solvent of 30 ml methanol in combination of 2 ml 20% concentration of NaOH. To synthesise, the aldehydes and ketones of all components are mixed in 30 mL of methanol and put in a conical flask. A magnetic bead was rinsed in water and briefly immersed in acetone before being introduced to the conical flask, which was then placed on the hot plate magnetic stirrer. To prevent teeming, a funnel was placed on the conical flask and agitated until the solution became clear. Then, NaOH (5ml, 20%) was gently added in the form of drops and stirred until the clear solution turned fuzzy. The stirring time is not the same for all samples; it varies by sample, and the details are mentioned in the Table1. The synthesis schemes of all the derivatives are shown in Fig.1-5. The synthesized compounds were further dissolved in Dimethylformamide (DMF) solvent and filtered after the solubility test for the single crystal growth by adopting slow evaporation solution growth method, , the saturated solutions of all the compounds in a beaker have been held at room temperature for nucleation with tight coverage, small nucleated crystals were noticed after few days and allowed to grow for well dimensional crystals. The grown crystals are further characterized from both destructive and non-destructive methods. Fig.1 Synthesis scheme of 9ACT 6  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Table.1 Synthesis details Stirring duration Compound Ketone Aldehyde in (Hour) 9ACT 2-acetyl thiophene 9-anthracene carboxaldehyde 1.5 (0.65 ml) (1.03g) 4BNB 4-nitro benzaldehyde 4-acetyl-4-bromobiphenyl 1 (0.97g) (1.64g) 4EDB 2,6–dichlorobenzaldehyde 4-acetyl-4-bromobiphenyl 2 (0.875g) (1.375g) 4EBD 4-(Benzyloxy) benzaldehyde 4-acetyl-4-bromobiphenyl 1.5 (1.06g) (1.375g) 9ECA 9-Anthracene carboxaldehyde 2-chloroacetophenone 1 (1.031g) (0.772g) Fig.2 Synthesis scheme of 4BNB Fig.3 Synthesis scheme of 4EDB 7 “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Fig.4 Synthesis scheme of 4EBD Fig.5 Synthesis scheme of 9ECA 8  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 6. Result and Discussion 6.1 Structural Details Crystallographic data of the structure mentioned were deposited with CCDC numbers 1914992 at the Cambridge Crystallographic Data Center. The 9ACT molecule was configured in orthorhombic pattern under centrosymmetric space group Pbca which was confirmed from the single crystal XRD analysis. The ball and stick structure of 9ACT is shown in below Figure 6. The Thiophene chalcone is structured via C5=C6 double bond 1.479Å with a torsion angle 176.0° between (C5-C6-C7-C8) links. The Thiophene ring is affected by the 𝜋 conjugation. The synthesized chalcone derivative is constituted in the structure with the following lattice parameters are ∝= 𝛽 = 𝛾 = 900 and 𝑎 = 14.4346Å 𝑏 = 9.7710 Å 𝑐 = 22.583Å. Fig.6 The Ball and stick structure of 9ACT 6.2 Fluorescence Photoluminescence spectroscopic analysis is a non-destructive method for applying the mark of luminescence of the optical component. The effect of fluorescence is shown by molecules which are aromatic or molecules containing multiple conjugated double bonds with a high degree of resonance steadiness. The photoluminescence emission spectrum was measured in the range 320 - 460 nm. They were collected with JY FLUOROLOG-3 Spectrofluorometer. The absence of intermediate emission peaks and a single colored emission is a sign that 9  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” crystals are extremely pure. These observed results authorize that the grown crystal have a Blue emission property under excitations. To get the fluorescence spectrum of a sample, it was stimulated at a selected wavelength of 320 nm and the peak value is observed at 467 nm and the plot is shown in figure.7. Fig.7 Fluorescence plot 6.3 Vibrational Analysis Among different characterization methods Fourier transform infrared (FTIR) spectroscopy is one of the most powerful tools for the determination of functional group in a compound together with possible molecular bonds between chemical compounds. To confirm the functional groups in the sample (9ACT), FTIR spectroscopic method was used to obtain the vibrational spectrums. The FT-IR spectrum was collected using Bruker-Alpha-Platinum ATR-IR spectrometer equipped with KBr pellet technique using Rock Solid Michelson Interferometer and a DTGS detector, in the range of 500-4000 cm-1, with resolution 2 cm-1. The FTIR vibrational peaks are observed in the figure 8. The various vibrational modes of synthesized 9ACT are observed as follows; the Aromatic C-H stretching modes of vibrations are observed in the region of 3111.2-3046 cm-1. The vibration of the stretching carbonyl group is very strong and appeared as a specific peak with maximum absorption in the standard region of 1664 cm -1. The C=O stretching mode of vibrations are noticed at 1644 cm -1for the compound 9ACT. The vibration stretching mode C=C for the compound 9ACT is scaled at 1600 and 1601 cm -1 respectively due to the hybrid 10  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” resonance. C=C and C- C stretching vibrations, together with bending vibration, are found in the scale between 1551.37 and1248 cm-1 for both derivatives. Further C-S stretching modes of vibration for the derivative are noticed in the region 896.24cm-1. The vibrational bands observed in the FTIR spectra confirm the functional groups and the structure of molecules. Fig.8 FTIR Spectrum of 9ACT 6.4 Thermal Analysis The thermal analyses corresponding to material stability, good crystallinity and sample purity were analyzed for the 9ACT sample through thermal analysis. The data for thermal analysis were obtained using simultaneous TG-DSC NETSCH STA 449 F3 Jupiter, Proteus 6.1.0 version. The temperature range is between 30 to 600 deg C. The thermal behavior and stability of the crystal were analyzed by thermogravimetric/ differential scanning calorimetry measurement/differential thermal analysis in N 2 atmosphere with a sample weight 4.695 mg. The sharp Peak at 101°C is sighted in the DSC curve, which corresponds to the melting point of the crystal. High-class crystallinity and purity have peered through peak sharpness in the DSC Curve. The smooth curve in DSC plot up to melting point indicates the toughness of the crystal against thermal crack. The TGA curve shows that the mass of the sample remains unchanged till 201.46 °C after that a minor weight loss about 2.16% was noticed before the melting point due to dehydration. A major weight loss of 93.58% was observed in the TGA plot between 28°C to 700°C and is due to the decomposition of the sample. 11  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” The TG curve in the plot shows the stability of the 9ACT sample until the melting point, after which there is about 2.16% weight loss was noticed inconsequence of dryness. The decomposition of the sample began at around 326.46 °C stays up to 246.46°C during which major weight loss about occurred. The Sharpness of the peak shows good degree of crystallinity and purity of the samples. The thermal gravimetric analysis (TGA), DSC and differential thermal gravimetric (DTG) curves of 9ACT sample are shown in figure.9. The weight loss at these temperatures is not due to the decomposition of the samples but due to vitalization. The major weight loss of about -2.69% (in the temperature range from 28°C to 700°Cm) for 9ACT is observed. The weight loss is due to the decomposition of the sample to gaseous phase. The DTG curve coincides with TGA also confirms the weight loss at particular temperature Range. The higher value of melting temperature and the stability of these Chalcones before the melting point confirms that these are the better Molecules for nonlinear device fabrications. 9ACT has better thermal stability than the previously reported chalcone materials. The high thermal stability crystals have a wide scope in the device fabrication. Fig.9 TG/DSC/DTG Curve 12  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 6.5 UV-Visible Spectral Analysis UV-Vis spectroscopy is an analytical technique that measures the amount of discrete wavelengths of UV or visible light that are absorbed by or transmitted through a sample in comparison to a reference or blank sample. This property is influenced by the sample composition, potentially providing information on what is in the sample and at what concentration. UV-Vis-NIR Spectroscopy measures the absorption spectrum of the compound over a range of wavelengths using a UV-Vis-NIR spectrophotometer. The linear optical properties have been analyzed with the help of UV-VIS spectrum. The spectral data were collected for the sample using UV-VIS double spectrophotometer in ethanol solution in the wavelength range 250 – 800nm at room temperature. The plotted UV-VIS spectrum of the sample is presented in figure.13. UV-Vis-NIR Absorption Properties: UV-Vis-NIR spectroscopy of 9ACT samples revealed a notable absence of absorption in the visible region, rendering them highly suitable for nonlinear optical (NLO) applications at room temperature. The absorption spectrum extended from the UV region into the violet region due to n-π* and π-π* transitions, arising from the presence of an aromatic ring and a C=O group ,. The transparency cut-off wavelength (λo) was determined to be 473.6 nm, corresponding to a significant band gap energy (Eg = hc/λo) of 2.8 eV. By enhancing the conjugation, these groups increase the absorbance of the π-π* transition at this wavelength. 400 nm is the observed cut-off wavelength for the 9ACT crystal. Tauc’s equation (𝛼ℎ𝜈) 2=(ℎ𝜈−𝐸𝑔) was used to determine the optical band gap of 9ACT, where A is the band gap constant, 𝛼 is the linear absorption coefficient, and Eg is the energy band gap. Plotting indicates that the optical band gap for 9ACT crystals was determined to be 2.8 eV. The obtained spectrum shows that the 9ACT crystal has a broad transparency range that extends above the 473 nm cut off wavelength and includes the whole visible and infrared areas. The material’s broad transparency and large band gap highlight its potential for a variety of NLO applications. We have conducted tests for all additional synthesized derivatives using the same methodology, and the corresponding results are shown in the table.2. All the samples spectra are depicted in the Fig.10-20. 13 “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Fig.10 Absorption spectra of 9ACT Fig.11 Optical band gap of 9ACT compound 14  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Table.2 Linear optical parameters of the synthesized compounds SL.No Name of the Absorption Cut-off Energy Transition Compound peak band gap 1 9ACT 371nm 473.6nm 2.8eV n -𝜋* Transition 2 4BNB 322nm 407nm 3.41eV n -𝜋* Transition 3 4EDB 294.4nm 355.6nm 3.6eV 𝜋 -𝜋* Transition 4 4EBD 290nm 320nm 3.92eV 𝜋 -𝜋* Transition 5 9ECA 371.2nm 452.8nm 2.82eV n -𝜋* Transition Fig.12 Absorption spectra of 4EBD Fig.13 Optical band gap of 4EBD compound 15 “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Fig.14 Absorption spectra of 4EDB compound Fig.15 Optical band gap of 4EDB compound 16 “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Fig.16 Absorption spectra of 4BNB compound Fig.17 Optical band gap of 4BNB compound 17 “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Fig.18 Absorption spectra of 9ECA compound Fig.19 Optical band gap of 9ECAcompound 18  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 6.6 Nonlinear Optical Studies In the present study, third-order nonlinear optical studies were carried out for 9ACT crystal using CW-DPSS laser source of output power 200 mW was operating at 532 nm to perform Z-scan tests , ,. The crystal 9ACT was dissolved in DMF solution, filled in a quartz cuvette of 1 mm in thickness and placed at the focus of the beam (Z = 0). In relation to the sample spot, the optically transmitted beam was traced using the detector mounted on the far field and the Z-scan transmission curves (open aperture and closed aperture) of 9ACT crystal are shown in Fig.20 and Fig.21. In DMF solution of 0.01 molar concentrations, the closed aperture and open aperture data were collected using Z-scan technique to explore the third order NLO properties of 9ACT. In the experimental circumstances, a 1 mm pathway quartz cuvette was used to fulfil the thickness condition as a result of 8.86 mm Rayleigh length (Z0). When the continuous wave laser beam was focused on the convex lens of beam size 38.74 mm and a focal length 286 mm, the closed aperture and open aperture data were simultaneously obtained, while at the focal point the strength was 8.48 × 107 Wm-2 measured. As the optical signal moves through the sample, the phase shift from peak to valley with the focus Z=0 is defined as a negative sign of nonlinear refraction (n2). The negative tendency of NLR (n2) is the identity characteristic of self-defocusing property of inherited material. The open aperture curve in Fig.19 shows the symmetric valley from the focus Z=0 recommends the positive NLA (β). In our experiment, the self-defocusing effect was caused by nonlinear thermal absorption of a tight focused CW laser beam that propagates by an absorbing medium, generating a distribution of the temporal temperature in the sample solution. By fitting the closed aperture curve using the relation (1), the closed aperture Z-scan data was used to measure the third order NLR (n2). (4ΧΔϕ )0 Τ(Z)= [1- ] (1) (Χ2 +1)(Χ2 +9) Where, T (Z) is the normalized transmittance, X = Z/Z0 ,"Δϕ (0.62) is the phase shift" and k is the wave vector (k = 2π/λ). The equation (2) can be used to calculate the n2. Δϕ0 n2 = (2) kI0 Leff Finally, the value (n2) was found to be -2.79 ×10-9 cm2/W. In order to test the non-linear absorption coefficient (NLA) and to have good acquaintance of the underlying mechanism for the optical nonlinearities, Z-scan measurements were performed using Sheik Bahae et al standard Open Aperture z-scan technique. The open 19  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” aperture curve for 9ACT was numerically fitted using the equation (3) to nonlinear transmittance for nonlinear absorption coefficient (β). β I0 Leff 𝑇 (𝑍 ) = 1 − (3) 2√2(1 + 𝑥 2 ) (1−𝑒 −𝛼𝐿 ) Where,𝐿𝑒𝑓𝑓 = , α is the linear absorption coefficient. The nonlinear absorption 𝛼 coefficient (β) for 9ACT was found to be 4.5× 10-5cm /W. The condition for the TPA process to take place is considered to be that when the material band gap is twice as high as the energy of excitation. The linear absorption spectrum exhibits a large absorption at a shorter wavelength (240–330 nm) and an absorption at a very low level at an excitation wavelength (532 nm), which fulfils the basic TPA requirement (2 hν σg). The determined NLA (β) and the NLR (n2) allowed us to calculate the third-order nonlinear optical susceptibility (χ (3)) with the equations (5), (6) and (7). 10−4 (𝜀0𝐶 2 𝑛02 𝑛2 ) 𝑅𝑒 𝜒 (3) (𝑒. 𝑠. 𝑢) = (5) 𝜋 10−2 (𝜀0 𝐶 2 𝑛0 𝛽𝜆) 𝐼𝑚 𝜒 (3)(𝑒. 𝑠. 𝑢) = (6) 𝜋 1/2 |𝜒 (3)| = [𝑅𝑒 𝜒 (3) (𝑒. 𝑠. 𝑢) + 𝐼𝑚 𝜒 (3) ] (7) Where, n0, ε0, n2, and β are the linear refractive index, permittivity of the free space, nonlinear absorption coefficient and nonlinear refractive index respectively. Owing to their use in laser switching systems for the safety of human eye and optical devices sensitive to extreme laser beams, optical power limiting devices play a vital role in photonics. Optical power limiters 20  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” have received considerable attention in this field. Therefore, the open aperture z-scan data was used to plot an optical limiting curve (Fig.22) to estimate the limiting threshold and found an outstanding limiting threshold value about 2.8 (kJ/cm 2) due to their RSA mechanism which is the essential parameter for a material one should process a good optical limiter. The shape of the curve in the plot indicates that at the lower fluence below the limiting threshold, the normalized transmittance is almost constant and further transmittance begins to decrease at higher fluence and the material displays less transmittance to the focused beam. Thus, the lower limiting threshold values calculated support the better optical limiting response. The 9ACT material meets the optical switching device requirement in conjunction with optical limiting device applications , , such as one photon figure of merit (W>1) and two photon figure of merit (T 1) and two-photon (T < 1) figures of merit with estimations W= 1.3 and T = 0.3 Hence, obviously the title compound has a vast scope in optoelectronic device applications. 23  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” 8. Scope for Further Research  In the present investigation, third-order NLO measurements were performed using the continuous wave laser and are thermal origin, this can be extended to picosecond, and femto-second laser pulses.  In applications like low-power degenerate four wave mixing, gating applications, etc., organic chalcones can be mixed in gelatin.  Recently, the study of material modification by ion-irradiation is catching the attention of researchers. It may be interesting to study the changes in properties of the crystals after irradiation of heavy ions. 24  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” References K. Naseema, K. B. Manjunatha, K. V. Sujith, G. Umesh, B. Kalluraya, and V. Rao, “Third order optical nonlinearity and optical limiting studies of propane hydrazides,” Opt. Mater. (Amst)., vol. 34, no. 11, pp. 1751–1757, 2012. H. C. Kwong, M. S. Rakesh, C. S. Chidan Kumar, S. R. Maidur, P. S. Patil, C. K. Quah, Y. F. Win, C. Parlak, and S. Chandraju, “Structure-property relation and third-order nonlinear optical studies of two new halogenated chalcones,” Zeitschrift fur Krist. - Cryst. Mater., vol. 233, no. 5, pp. 349–360, 2018. L. Kamath, K. B. Manjunatha, S. Shettigar, G. Umesh, B. Narayana, S. Samshuddin, and B. K. Sarojini, “Optics & Laser Technology Investigation of third-order nonlinear and optical power limiting properties of terphenyl derivatives,” vol. 56, pp. 425–429, 2014. A. Singh, “Nonlinear optical properties of nanostructures , photochromic and lanthanide complexes in solution Présentée par pour obtenir le grade de Propriétés optiques non linéaires de nanostructures , de complexes photochromes et de complexes de lanthanides en sol,” 2013. P. Sonar, S. P. Singh, P. Leclère, M. Surin, R. Lazzaroni, T. T. Lin, A. Dodabalapur, and A. Sellinger, “Synthesis, characterization and comparative study of thiophene- benzothiadiazole based donor-acceptor-donor (D-A-D) materials,” J. Mater. Chem., vol. 19, no. 20, pp. 3228–3237, 2009. A. Irfan, A. G. Al-Sehemi, A. R. Chaudhry, and S. Muhammad, “How methoxy groups change nature of the thiophene based heterocyclic chalcones from p-channel to ambipolar transport semiconducting materials,” J. King Saud Univ. - Sci., 2017. V. Pr, A. Jayarama, K. Cs, Y. Narayana, K. Byrappa, M. K. S, and S. Kumar, “Synthesis, Single Crystal Structure and Spectroscopic Aspects of Chalcone 2(2E)-1-(4′-bromobiphenyl-4-yl)-3- (2, 3-dimethoxybenzaldhyde)prop-2-ene-1-one,” Chem. Data Collect., vol. 2, 2017. P. S. Patil, S. R. Maidur, S. V. Rao, and S. M. Dharmaprakash, “Optics & Laser Technology Crystalline perfection , third-order nonlinear optical properties and optical limiting studies of 3 , 4- Dimethoxy -4 ′ -methoxychalcone single crystal,” Opt. Laser Technol., vol. 81, pp. 70–76, 2016. A. N. Prabhu, A. Jayarama, K. S. Bhat, K. B. Manjunatha, G. Umesh, and V. Upadhyaya, “Physicochemical Studies on Thienyl Chalcone Derivative for Nonlinear Optical Application,” vol. 2013, pp. 5–10, 2013. A. Jayarama, H. J. Ravindra, and S. M. Dharmaprakash, “Crystal growth , characterization , structural characteristics and second harmonic generation in N -benzoyl glycine crystals,” vol. 113, pp. 91–95, 2009. M. N. Arshad, A.-A. M. Al-Dies, A. M. Asiri, M. Khalid, A. S. Birinji, K. A. Al-Amry, and A. A. C. Braga, “Synthesis, crystal structures, spectroscopic and nonlinear optical properties of chalcone derivatives: A combined experimental and theoretical study,” J. Mol. Struct., vol. 1141, pp. 142–156, 2017. A. Ekbote, P. S. Patil, S. R. Maidur, and T. Shyang, “Dyes and Pigments Structural , third- order optical nonlinearities and fi gures of merit of under CW regime : New chalcone derivatives for optical limiting applications,” Dye. Pigment., vol. 139, pp. 720–729, 2017. K. Naseema, K. V. Sujith, K. B. Manjunatha, B. Kalluraya, G. Umesh, and V. Rao, “Synthesis, characterization and studies on the nonlinear optical parameters of hydrazones,” Opt. Laser Technol., vol. 42, no. 5, pp. 741–748, 2010. A. J. Kiran, H. W. Lee, H. J. Ravindra, S. M. Dharmaprakash, K. Kim, H. Lim, and F. 25  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Rotermund, “Designing novel chalcone single crystals with ultrafast nonlinear optical responses and large multi-photon absorption coefficients,” Curr. Appl. Phys., vol. 10, no. 5, pp. 1290–1296, 2010. H. Davanagere, J. A, P. S. G. Patil, S. R. Maidur, C. K. Quah, and H. C. Kwong, “The structural and third-order nonlinear optical studies of a novel nitro group-substituted chalcone derivative for nonlinear optical applications,” Appl. Phys. A, vol. 125, no. 5, p. 309, 2019. P. S. Patil, M. S. Bannur, D. B. Badigannavar, and S. M. Dharmaprakash, “Optics & Laser Technology Study on nonlinear optical properties,” Opt. Laser Technol., vol. 55, pp. 37–41, 2014. S. Satheeshchandra, D. Haleshappa, S. Rohith, A. Jayarama, and N. Shetty, “Novel benzofuran based chalcone material for potential nonlinear optical application,” Phys. B Condens. Matter, vol. 560, no. January, pp. 191–196, 2019. N. Rao, “Title : D-A- π -D SYNTHETIC APPROACH FOR THIENYL CHALCONES – NLO- A STRUCTURE ACTIVITY STUDY ( JPC 10163 ),” "Journal Photochem. Photobiol. A Chem., 2016. S. Raghavendra, A. Jayarama, T. C. S. Shetty, and S. M. Dharmaprakash, “Linear Optical and SHG Characterization of New Chalcone Crystals,” pp. 1–3, 2013. P. Praveena, B. K. Sarojini, and S. Madan Kumar, “Mechanochemical synthesis and characterizations of chalcone derivatives: (2E)-3-[4-(Benzyloxy)phenyl]-1-(thiophen-2-yl)prop ‑2-en- 1-one and (2E)-3-(Anthracen-9-yl)-1- (thiophen-2-yl)prop‑2-en-1-one,” Chem. Data Collect., vol. 24, 2019. D. B. A. Kumar, G. K. Prakash, M. N. Kumaraswamy, B. P. Nandeshwarappa, B. S. Sherigara, and K. M. Mahadevan, “Microwave assisted facile synthesis of amino pyrimidines bearing benzofuran and investigation of their antimicrobial activity,” Indian J. Chem. - Sect. B Org. Med. Chem., vol. 45, no. 7, pp. 1699–1703, 2006. P. Przybylski, K. Pyta-Klich, K. Pyta, and A. Janas, “Cascade reactions as efficient and universal tools for construction and modification of 6-, 5-, 4- and 3-membered sulfur heterocycles of biological relevance,” Tetrahedron, vol. 74, no. 44, pp. 6335–6365, 2018. K. R. Harshitha, B. K. Sarojini, B. Narayana, A. G. Lobo, S. M. Kumar, and K. Byrappa, “Single crystal X-ray studies and Hirshfeld surface analysis of ethoxy phenyl substituted chalcone derivatives,” Chem. Data Collect., vol. 17–18, pp. 121–131, 2018. M. Lamim, L. Domeneghini, L. Rosaria, S. Dias, L. Kramer, T. Regina, A. Mascarello, M. Steindel, R. Augusto, H. Carla, R. José, and C. Rangel, “Bioorganic & Medicinal Chemistry Trimethoxy-chalcone derivatives inhibit growth of Leishmania braziliensis : Synthesis , biological evaluation , molecular modeling and structure – activity relationship ( SAR ),” Bioorg. Med. Chem., vol. 19, no. 16, pp. 5046–5052, 2011. D. Haleshappa, A. Jayarama, R. Bairy, S. Acharya, and P. S. Patil, “Second and third order nonlinear optical studies of a novel thiophene substituted chalcone derivative,” Phys. B Condens. Matter, vol. 555, no. September 2018, pp. 125–132, 2019. D. Haleshappa, A. Jayarama, C. Kheng, and H. Chong, “Physica B : Physics of Condensed Matter A novel bromo-substituted thiophene based centrosymmetric crystals : Thermal , mechanical , and third order NLO properties for the optical limiting applications,” Phys. B Phys. Condens. Matter, vol. 585, no. February, p. 412083, 2020. D.Haleshappa, J. A, C. K. Quah, H. C. Kwong, and P. S. Patil, “Investigation of structural, physical, linear, and nonlinear optical properties of two novel thiophene centred D-π-A type push-pull organic derivatives for nonlinear optical applications,” J. Mol. Struct., vol. 1220, p. 128763, 2020. D. Haleshappa, A. Jayarama, and P. Shankaragouda, “Materials Today : Proceedings 26  “A structural and nonlinear optical investigation on a centrosymmetric organic chalcone” Structure and property relationship of methoxy substituted novel organic crystals for photonic applications,” Mater. Today Proc., no. xxxx, 2020. A. Ekbote, P. S. Patil, S. R. Maidur, T. S. Chia, and C. K. Quah, “Structural, third-order optical nonlinearities and figures of merit of (E)-1-(3-substituted phenyl)-3-(4-fluorophenyl) prop-2- en-1-one under CW regime: New chalcone derivatives for optical limiting applications,” Dye. Pigment., vol. 139, pp. 720–729, 2017. A. Ekbote, P. S. Patil, S. R. Maidur, T. S. Chia, and C. K. Quah, “Structure and nonlinear optical properties of (E)-1-(4-aminophenyl)-3-(3-chlorophenyl) prop-2-en-1-one: A promising new D- π-A-π-D type chalcone derivative crystal for nonlinear optical devices,” J. Mol. Struct., vol. 1129, pp. 239–247, 2017. P. P. Vinaya, A. N. Prabhu, K. S. Bhat, and V. Upadhyaya, “Synthesis , growth and characterization of a long-chain π-conjugation based methoxy chalcone derivative single crystal ; a third order nonlinear optical material for optical limiting applications,” vol. 89, no. September 2018, pp. 419–429, 2019. S. R. Maidur, J. R. Jahagirdar, P. Shankaragouda, T. Shyang, and C. Kheng, “Structural characterizations , Hirshfeld surface analyses , and third- order nonlinear optical properties of two novel chalcone derivatives,” Opt. Mater. (Amst)., vol. 75, pp. 580–594, 2018. N. Priyadarshani, G. Vinitha, and T. C. Sabari Girisun, “Third order nonlinear optical properties of monoclinic and orthorhombic CuNb2O6 under CW laser illumination,” Opt. Laser Technol., vol. 108, pp. 287–294, 2018. 27