UV-visible Studies Research Articles

Synthesis and Characterization of a New Non-Linear Optical Material: (4-Chlorophenyl)(4-Hydroxypiperidin-1-yl) Methanone

A new organic and nonlinear optical material namely (4-chlorophenyl) (4-hydroxypiperidin-1-yl) methanone [HPCP] was synthesized from the mixture of 4-hydroxypiperidiene, triethylamine, and 4-chlorobenzoyl chloride by solution growth technique. The 3D structure of the title crystal has been derived using the X-ray diffraction (XRD) spectrum. The compound was crystallized in the orthorhombic crystal system with non-centrosymmetric space group Pca21. Optical properties of the as-grown compound have been elucidated through 1H-NMR, UV-Visible, FTIR, and PL spectral studies. The melting point, stages of mass decay, and thermal stability of the synthesized material were obtained by TG/DTA thermal analysis. Vickers microhardness test was performed to comprehend its mechanical strength. The second harmonic generation (SHG) efficiency was estimated by employing Q-switched high energy, Nd: YAG the laser source, and the SHG efficiency was found to be 1.73 times that of KDP, the reference crystal.

Role of Aromatic Heterocyclic Core-Based Materials as Donors for Organic and as Hole-Transporting Materials for Perovskites Solar cells

Hole-transporting materials (HTMs) have revolutionized the field of photovoltaics for solar cell devices. Herein, novel butterfly-shaped hole transport material (HTM) 2,7-DMPZ (R) containing twisted core unit is used to develop novel molecules (Q1–Q6) by fitting suitable donor groups at peripheral regions of 2,7-DMPZ. To investigate the power conversion efficiency (PCE) of Q1–Q6, different analyses, including optical, frontier molecular orbitals (FMOs), molecular electrostatic potential (MEP), density of states (DOS), transition density of states (TDM), and charge transfer (CT) analysis are employed using various density functional theory (DFT) and time-dependent-DFT (TD-DFT) approaches. Excitation, binding, and reorganization energy along with open-circuit voltage of Q1–Q6 molecules are estimated. The UV–Visible study elucidates that these molecules exhibited redshifts (329–343[Formula: see text]nm) absorption higher and comparable with the R molecule (342[Formula: see text]nm). The HOMO–LUMO gap of Q1–Q6 (5.31–5.38[Formula: see text]eV) is also narrower than R (5.49[Formula: see text]eV), indicating that designed molecules can show higher charge transfer than R, which can ultimately produce higher PCE values. In case of hole reorganization energy, the hole mobilities are found more valuable than R. For charge transfer analysis, the Q6 molecule is complexed with PC[Formula: see text]BM acceptor polymer that shows promising charge transfer between the Q6/PC[Formula: see text]BM complex. All studies illustrate that proposed molecules (Q1–Q6) have a great capacity to further improve the optical and photovoltaic parameters when they will be used in efficient organic (as donors) and perovskite (as HTM) solar cells and can show higher performances than R. Therefore, these newly designed molecules (Q1–Q6) rerecommended to the experimentalists for the synthesis to be employed as donors in organic and as HTMs in perovskite solar cells applications.

Growth, structural effects, and non-linear and spectroscopic properties of nanocomposites based on α-NiSO4·6H2O single crystals with TiO2 nanoparticles or sols

Nanocomposites based on nickel sulfate hexahydrate α-NiSO4·6H2O (NSH) with titanium (IV) oxide introduced in the form of nanoparticles (Hombifine N: anatase; Degussa P25: 85 % anatase + 15 % rutile; η-phase: 86 % η - phase + 14 % anatase, NSH:Ti(1)) or sols (NSH:Ti(2)) are synthesized for the first time. X-ray diffraction study reveals a single-phase nature of samples, the full occupancy of all crystallographic sites in the NSH:Ti(1) structures, and the presence of Ti4+ ions in interstitial sites near the vacant Ni site in the NSH:Ti(2) structures. A crystallization of the nanosized η-phase of the composition TiO2-x × mH2O directly in the NSH:Ti(1) crystalline matrix with the formation of TiO2 with the rutile structure, facilitated by the structural-geometric correspondence of 2D projections of NSH and rutile, is observed for the first time. The presence of TiO2 in the interblock space of NSH:Ti(1) crystals affects the unit cell parameters due to the induced stresses, which is practically not described in the literature. The intensity of SHG signals of NSH:Ti varies depending on both the prehistory of TiO2 samples and the crystal state, single-crystal or powdered, of the object under study: the highest values were observed for the NSH:Ti(2) powder with the lowest content of titanium ions. The UV–VIS study reveals similar absorption and transmission bands, but with little difference in band width and intensity, for NSH, NSH:Ti(1) and NSH:Ti(2), which can be perspective for UV filters operating in the solar-blind range.

Giant NLO response and deep ultraviolet transparency of dual (alkali/alkaline earth) metals doped C6O6Li6 electrides

The designing of new materials having outstanding nonlinear optical (NLO) response is much needed for use in latest optics. Herein, the geometric, electronic and NLO properties of alkali and alkaline earth metals doped C6O6Li6 (alk-C6O6Li6-alkearth, alkearth = Ca, Mg, Be and alk = K, Na, Li) electrides is studied via quantum chemical approach. The interaction energies (Eint) are examined to illustrate their thermodynamic stability. The strong interaction energy of -39.99 kcal mol-1 is observed for Ca–C6O6Li6–Li electride in comparison to others. Frontier molecular orbitals (FMOs) energy gap of considered complexes is changed due to the electronic density shifting between metals and C6O6Li6 surface, which notifies the semi conducting properties of these electrides. The FMOs isodensities and natural bond orbital (NBO) charge analysis are performed to justify charge transfer between dopants and complexant. UV–Visible study also confirmed the application of these electrides as deep ultra-violet laser devices. NLO response is studied through calculation of first hyperpolarizability (βo). The highest βo value of 1.68 × 105 au is calculated for Mg–C6O6Li6–K electride. NLO response is further rationalized by three- and two-level models approach.

Influence of azo-based donor modifications on nonlinear optical amplitude of D-π-A based organic chromophores: A DFT/TD-DFT exploration

Organic heterocyclic fused ring compounds possess remarkable nonlinear optical (NLO) amplitude, are potentially employed in optical computing and nano-photonics. Herein, ITTBCR1 was quantum chemically modified into a series of novel D-π-A configured NLO compounds (ITTBCD2-ITTBCD6) by substituting various efficient donor moieties. To investigate the electronic, photophysical, and NLO properties, ITTBCR1 and ITTBCD2-ITTBCD6 were subjected to density functional theory (DFT) and time-dependent DFT calculations at M06/6–311 G(d,p) level of theory. Frontier molecular orbital analysis (FMOs) illustrated that the newly designed chromophores exhibit smaller energy gaps (1.625–2.013 eV) compared to ITTBCR1 (2.384 eV). The global reactivity parameters estimated through Egap revealed higher softness (σ = 0.49–0.61 Eh) values, implying enhanced reactivity of ITTBCD2-ITTBCD6 compounds. An efficient push-pull mechanism disclosed positive charges on donors and π-spacers, while the acceptor moieties exhibited a negative charge. The presence of charge separation states and the substantial involvement of molecular orbitals in the charge transfer were explored by natural bond orbitals (NBOs), transition density matrix and density of states analyses. The UV-Vis study of the designed compounds displayed larger bathochromic shifts with wider absorption spectra. Also, a significantly large NLO behavior was found in all the novel entities (ITTBCD2-ITTBCD6), thus potentially employable as NLO materials. Inclusively, compound ITTBCD5 demonstrated highest linear polarizability (〈α〉 = 2.250 ×103a.u.), and first hyperpolarizability (βtot = 70.155 ×104a.u.), therefore proposed as the most proficient NLO material. Comparative study for NLO properties at various functional showed that at M06/6–311 G (d,p) significant NLO results could be obtained. The current investigation revealed that by controlling the type of donor motifs, numerous NLO compounds can be designed, which are equally productive in hi-tech NLO applications.

Photophysical, Antioxidant, Antibacterial and NBO, LOL, ELF Analysis of Alkyl Groups Substituted Calix[4]resorcinarenes.

In our work to investigate the photophysical, antioxidant, antibacterial, DFT and topological analysis of four C-alkyl calix[4]resorcinarenes (3a-3d - C4RAs). The photophysical properties of C4RAs in selected solvents were recorded using both UV-Visible and fluorescence spectral studies. The absorption and emission maximum of four C4RAs were observed around 280 nm and 318 nm in selected solvents. The solvatochromism with selected solvents were analysed from the plot between Stoke's shift and ETN. The antioxidant activity and antibacterial activity of four C4RAs were evaluated by phosphomolybdate assay and Kirby-Bauer method. The structure of four C4RAs was optimized using DFT B3LYP 6-311G method to calculating the various theoretical parameters in the gas phase. The stability, reactivity, formation of hydrogen bond, donor-acceptor interactions were reported from the interpretation of theoretical values. The non-covalent interactions of four C4RAs were characterized by LOL and ELF topological analysis.

Facile Processing of Unsubstituted π-Conjugated Aromatic Polymers through Water-solubilization Using Aromatic Micelles.

π-Conjugated aromatic polymers (πCAPs) are central components of functional materials yet suffer from insolubility without multiple covalent substituents on their backbones. We herein disclose a new strategy for the facile processing of unsubstituted heterocyclic πCAPs (i.e., poly(para-phenylene-2,6-benzobisoxazole) and poly(benzimidazobenzo-phenanthroline)), independent of the polymer length, via non-covalent encircling with aromatic micelles, composed of bent aromatic amphiphiles, in water. The UV/Visible studies reveal that the efficiencies of the present encircling method are ≈10 to 50-fold higher than those using conventional amphiphiles under the same conditions. The AFM and SEM analyses of the resultant aqueous polymer composites show that otherwise insoluble πCAPs form fine bundles (e.g., ≈1 nm in thickness) in the tubular aromatic micelles, through efficient π-stacking interactions. In the same way, pristine poly(para-phenylene) can be dissolved in water, displaying enhanced fluorescence (10-fold), relative to the polymer solid. Two types of unsubstituted πCAPs are likewise co-encircled in water, indicated by UV/Visible analysis. Importantly, aqueous processing of the encircled πCAPs into free-standing single- or multicomponent films with submicrometer thickness is demonstrated through a simple filtration-annealing protocol.

Synthesis of multi fluorine containing polyoxometalate sandwich type compound with drug delivery, DNA interaction and protein binding studies

The combination of polyoxometalates (POMs) and fluorinated anhydride in a variety of modes ofinteractionturned out to be the key for unlocking new directions in the study of biological activities. In this study, two new compounds such as a sandwich type covalently attached fluorinated anhydride [C27H24F6N2O10](FDA-Di-Tris) and a Dawson POM hybrid, [{N(C4H9)4}10 {C22H16F6N2O128P4V6W30·CH3CN}](FDA@Di-POM) were synthesized. These compounds were clearly characterized and their formation was confirmed by spectroscopic(UV–visible, FT-IR, NMR) techniques, elemental analyses and scanning electron microscopy techniques(SEM). FDA-Di-Tris and FDA@Di-POM were evaluated for drug delivery, DNA binding and protein binding. It is found that drug loading efficiency was 82% and 57% for FDA@Di-POM and FDA-Di-Tris,respectively. While drug release for FDA-Di-Tris was found to be lowest (14%) in basic media (pH = 11) and highest (59%) in acidic media (pH = 3) and FDA@Di-POM exhibited approximately similar behavior in both media such as (55%) in basic media (pH = 11) and (49%) in acidic media (pH = 3) respectively. UV–visible study of FDA-Di-Tris and FDA@Di-POM with salmon sperm DNA (SS-DNA) showed hypochromism trend which indicate intercalation mode of attachment and exhibited binding constant value 6.29 × 105M−1 and 8.33 × 105 M−1 for FDA-Di-Tris and FDA@Di-POM, respectively, referring that FDA@Di-POM has more binding affinity than FDA-Di-Tris. Protein binding study presented binding constant value (Kb) FDA@Di-POM and FDA-Di-Tris, which are 2.28 × 108 M−1 and 1.55 108 M−1, correspondingly.

Building Block Engineering toward Realizing High-Performance Electrochromic Materials and Glucose Biosensing Platform.

The molecular engineering of conjugated systems has proven to be an effective method for understanding structure-property relationships toward the advancement of optoelectronic properties and biosensing characteristics. Herein, a series of three thieno[3,4-c]pyrrole-4,6-dione (TPD)-based conjugated monomers, modified with electron-rich selenophene, 3,4-ethylenedioxythiophene (EDOT), or both building blocks (Se-TPD, EDOT-TPD, and EDOT-Se-TPD), were synthesized using Stille cross-coupling and electrochemically polymerized, and their electrochromic properties and applications in a glucose biosensing platform were explored. The influence of structural modification on electrochemical, electronic, optical, and biosensing properties was systematically investigated. The results showed that the cyclic voltammograms of EDOT-containing materials displayed a high charge capacity over a wide range of scan rates representing a quick charge propagation, making them appropriate materials for high-performance supercapacitor devices. UV-Vis studies revealed that EDOT-based materials presented wide-range absorptions, and thus low optical band gaps. These two EDOT-modified materials also exhibited superior optical contrasts and fast switching times, and further displayed multi-color properties in their neutral and fully oxidized states, enabling them to be promising materials for constructing advanced electrochromic devices. In the context of biosensing applications, a selenophene-containing polymer showed markedly lower performance, specifically in signal intensity and stability, which was attributed to the improper localization of biomolecules on the polymer surface. Overall, we demonstrated that relatively small changes in the structure had a significant impact on both optoelectronic and biosensing properties for TPD-based donor-acceptor polymers.

Synthesis, Characterization, Optical and Luminescence Properties of Copper Based Metal Organic Frame Works

Herein, we report synthesis of two new copper metal organic frameworks. The organic linkers were terephthalic acid with 6-Dihydroimidazo[2,1-b]thiazole-2-carbaldehyde and terephthalic acid with 3-benzothiazol-2-yl-malonaldehyde used in the copper nano metal organic framework (MOF). Both the Cu-MOF’s were characterized by XRD, UV-vis spectroscopy and FTIR. XRD crystallographic studies revealed the presence of copper metal at 2θ at 18.4°. Tauc plots were simulated to calculate the band gap of both Cu-MOF’s and result indicated the band gap energy of Cu-MOF 1 at 3.31 eV and for Cu-MOF 2 was at 3.57 eV. The UV-Visible absorption studies indicated two bands for Cu-MOF 1 and Cu-MOF 2 at 326 nm. However, the second band in Cu MOF 1 at 509 nm was slightly shifted to higher wavelength at 516 nm in Cu-MOF 2 due to the extension of π-π* transition. The photoluminescent properties of both Cu-MOF’s indicated a strong band at 505 nm. Thus, the optical properties of both the Cu-MOF’s infers that these can be a promising semiconductor material for various electronic applications.

Processing of Nb doped hematite for visible light photocatalytic reduction of noxious methylene blue

In this work, pristine Fe2O3 (FO, hematite) and Nb-doped Fe2O3 nanostructures with varying doping concentrations of 5%, 10%, and 15% are synthesized with hydrothermal technique. The purpose of this study is to determine the impact of doping concentration on photocatalytic activity toward mineralization of methylene blue (MB). Multiple instruments were utilized to examine the structures and functionalities of the pristine Fe2O3 (FO, hematite) and Nb-doped Fe2O3 nanostructure. The utilization of physiochemical techniques has confirmed the incorporation of Nb3+ ions into hematite. The Scherrer formula was employed to investigate the size of crystal of synthetically manufactured nanomaterials. The average particle size of undoped samples was determined to be 58 nm, while in doped samples the average nanostructure size was found to be 37 nm. The utilization of scanning electron microscopy (SEM) shows that Nb ions were able to enhance surface area and reduced particle aggregation. The band gap of FO, 5%-NFO, 10%-NFO, and 15%-NFO synthesized materials are 2.3, 2.2, 2.07 and 1.93 eV measured with UV Vis study. The exceptional photocatalytic characteristics of doped FO is attributed to a decrease in band gap energy. After 100 min, the highest level of methylene blue (MB) degradation was attained by 10%-NFO. The optimized concentration of 10%-NFO, a photocatalyst possessing a high electron trapping capacity, enhance the photoreduction process of organic dye.

Interface engineered nanostructured phase formation at Se/In sites by Ag ion irradiation and its structural, optical and morphological behavior

Thermally evaporated Se/In bilayer films were irradiated by 120 MeV Ag ion at different fluences. Energy-dispersive X-ray fluorescence (EDXRF) spectra of the films showed the 1:2 ratio concentration of In and Se. After six months of preserving the films under ambient condition, four phases: In2Se3, In4Se3, In and Se developed in the films as revealed by Grazing incidence X-ray diffraction (GIXRD) study. The In4Se3 and In were completely insensitive to the irradiation while the other two phases (In2Se3 and Se) were completely amorphized at high ion fluences. The Poission fitting of the fluence dependence area under X-ray diffraction (XRD) peaks showed the radius of amorphized latent tracks along the path of 120 MeV Ag ions in In2Se3 and Se as 8.4 nm and 9.5 nm respectively. The lattice fringe images of High-resolution transmission electron microscopy (HRTEM) showed the presence of the four phases as observed by GIXRD study. The UV-visible study revealed the band gap reduction at the low fluence region from pristine to 3 × 1011ions cm−2 and increased at high fluence from 1 × 1012 ions cm-2 to 1 × 1013 ions cm-2. This variation of band gap may be due to the formation of localized states and annealing effect due to ion irradiation. Field emission scanning electron microscopy (FESEM) images showed the nano needle shaped structure formation at 1 × 1012 ions cm−2 which increased with ion fluences. The appearance of needle shaped structures may be due to the In2Se3 phase. The I-V study showed the excellent current response in mA range which enables the films for various electrical applications. The surface wettability study showed the hydrophobicity nature of the films which enables it for application in different coating materials.

Micellization of phenothiazine drug and nonionic surfactant TX-165 mixture in different composition and media: surface tension and UV-visible study

ABSTRACT Micelles serve as a replica for the investigation of bio-membranes as physicochemical association of drugs with micelles is envisioned as their interconnection with bio-membranes. Micellization properties of promethazine hydrochloride (PMT) with TX-165 (a nonionic surfactant) in aqueous, 50 mmolkg−1 NaCl and 500 mmolkg−1 urea solutions were analysed in detail using surface tension measuring tool. PMT is employed as an analgesic, anticholinergic, sedative, antihistaminic as well as antipsychotic drug. UV-visible spectroscopy is also utilised to evaluate PMT-TX-165 interactions in an aqueous solution. Pure constituent and their mixtures (PMT + TX-165) of each composition showed lower cmc value in NaCl than in the aqueous system, while urea-containing solutions showed higher cmc value. Increasing the mole fraction (α 1) of TX-165 in mixed systems increases the interaction between the employed constituents (PMT and TX-165). The evaluated Gibbs free energy values of singular, and mixed system in each media were attained negative that uncovering that each system depicted the spontaneity of micellization. Various thermodynamic parameters were examined and discussed thoroughly. A UV-visible measurement also confirms that the components interact in treaty with surface tension measurements. Based on the results of this study, TX-165 was designed in a forthright manner, which could be an efficient drug delivery vehicle for phenothiazine drugs.

Effect of urea on optical properties of potassium hydrogen phthalate (KHP) single crystals for NLO applications

Semi-organic carbamide (urea) doped potassium hydrogen phthalate (KHP) crystals grown from slow evaporation solution growth technique. The grown crystals were subjected to powder XRD analysis and doped KHP crystallizes in orthorhombic structure with space group Pca21. FTIR spectrum confirms the presence of major functional groups and shows minor distortion of functional groups due to effect of dopant. SEM studies revealed, the effectiveness urea dopant on surface morphology of grown crystals. From thermal studies, it is found that, both undoped and urea doped KHP were stable up to 300 °C. UV–Visible studies showed, the grown crystals were transparent in the entire visible region and calculated optical band gap from Tauc’s plots. The SHG studies of the grown crystals have been confirmed by Kurtz-Perry powder technique.

THE EFFECT OF CALCINATION TEMPERATURES ON THE PROPERTIES OF ZNO NANOPARTICLES SYNTHESIZED BY USING LEAVES EXTRACTS OF PINUS BRUTIA TREE

Pinus Brutia (PB) tree leaf extracts were used to produce zinc oxide (ZnO) nanoparticles. The study of the PB tree extracts at several calcination temperatures from (200 to 500) oC on the formation of ZnO NPs' characteristics has been investigated using various characterization techniques. The chosen plant PB had its findings at both examinations of FTIR and UV-Visible spectroscopies shown and offered to be a superior option for the GS ZnO NPs at various pH levels. PB tree leaf extracts' UV-visible spectra revealed one distinguishable absorption peak at 275.3 nm. The study of the FESEM results showed that the Green Synthesized (GS) ZnO NPs' orientation, shape, and dimensions are significantly impacted by the calcination temperatures. The ZnO NPs are also shown by the XRD data to have hexagonal wurtzite crystal structures that have particle sizes at (002) peak falling within the range between (10 to 24) nm. The UV-Visible study of the ZnO NPs showed a strong peak absorbance for ZnO NPs that were calcined at various temperatures, with high UV absorption below 400 nm. The obtained energy band gap (Eg) is located in the region between (2.65 and 2.747) eV, narrowing as the calcination temperature rises. The ZnO NPs that were calcined at a temperature of 500 oC also had superior quality and outperformed those produced at other calcination temperatures, according to all of the analyzed results and properties of the ZnO NPs.

Aldehyde-functionalized cellulose as reactive sorbents for the capture and retention of polyamine odor molecules associated with chronic wounds

Aldehyde-functionalized cellulose (AFC) was prepared by oxidizing cellulose with sodium metaperiodate. The reaction was characterized by Schiff's test, FT-IR, and UV–vis study. AFC was evaluated as a reactive sorbent for controlling polyamine-based odor from chronic wounds, and its performance was compared with charcoal, one of the most widely utilized odor-control sorbents through physisorption. Cadaverine was used as the model odor molecule. A liquid chromatography/mass spectrometry (LC/MS) method was established to quantify the compound. AFC was found to rapidly react with cadaverine through the Schiff-base reaction, which was confirmed by FT-IR, visual observation, CHN elemental analysis, and the ninhydrin test. The sorption and desorption behaviors of cadaverine onto AFC were quantified. With clinic-relevant cadaverine concentrations, AFC demonstrated much better sorption performance than charcoal. At even higher cadaverine concentrations charcoal showed higher sorption capacity, probably due to its high surface area. On the other hand, in desorption studies, AFC retained much more of the sorbed cadaverine than charcoal. When AFC and charcoal were combined, the pair demonstrated excellent sorption and desorption behaviors. The XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay confirmed that AFC has very good in vitro biocompatibility. These results suggest that AFC-based reactive sorption can be a new strategy to control odors associated with chronic wounds for improved healthcare.

Investigation on structural, photoluminescence and magnetic behavior of Mn–ZnO nanoparticles via solvothermal route

Mn doped ZnO (Zn: Mn) nanopowder is successfully synthesized using the solvothermal route with concentration (X = 2%–8%) and annealing at 450 °C. The resulting material is investigated using various techniques. XRD studies confirm the structure of hexagonal wurtzite and good crystallinity in nature. From FESEM analysis confirms the formation of nanoparticles and allows for evaluation of the particle size of the sample. UV–Vis studies are used to determine absorbance wavelength and energy bandgap values. PL and EPR spectra confirm of the existence of zinc vacancy defects and g values are calculated. Interestingly, magnetic measurements revealed that the low concentration exhibited superparamagnetic behavior, while the high concentration showed a soft ferromagnetic structure using VSM.

UV–vis Study on β‐Cyclodextrin as Dual Function for Synthesis AgNPs and Antibacterial Application

AbstractThe current study reveals the synthesis of silver nanoparticles (AgNPs) with β‐cyclodextrin (β‐CDs) as a dual function, reducing, and stabilizing agent. UV–vis study is carried out to monitor the optimum condition of AgNPs formation. It is observed that setting pH at 12, 1:33 concentration ratio of AgNO3 to β‐CDs, and 5 min of incubation time are the optimum condition to synthesize AgNPs. The stability of AgNPs 4 weeks after synthesized is confirmed by the UV–vis spectra. Fourier transform infrared (FTIR) characterization reveals there is a peak appearing assigned to C=O which proves a redox reaction occurs between AgNO3 and β‐CDs. Gram‐positive (Bacillus subtilis and Staphylococcus aureus) and Gram‐negative bacteria (Escherichia coli and Pseudomonas aeruginosa) are tested to investigate the antibacterial activity of AgNPs. This study shows that AgNPs exhibit inhibition of bacterial growth.

Structural morphological and band gap studies of Al doping in BaSnO3

In this work the role of Al as dopant in BaSnO3 is explored through structural, morphological, compositional and optical studies. The Perovskite structured pure BaSnO3 (BSO) and Al doped BSO 3D nano particles were synthesised through coprecipitation method at pH-13 using BaCO3, SnCl4 and Al2O3 as precursors. Al doped BSO was prepared by mixing BSO (taken from oven before calcinations) with Al2O3 through mortar pestle for one hour and then calcined it at 1100℃ and name it as Al doped BSO. The structural, morphological, compositional and optical studies were carried out through XRD, FESEM, XPS and Uv–Vis spectroscopy respectively. The pure and doped BSO XRD studies reveal that Al doped BSO is a multiphase material with SnO2 as a dominant phase while in pure BSO SnO2 phase was present as impurity phase. The XRD results are in correlation with the XPS results. Through XPS it is observed that Al is active dopant which suppresses the Ba incorporation in BSO and hence results in suppressed BSO phase in Al doped BSO. XPS confirms the Al doping and the spin orbit splitting energy at 8.5 eV of Sn signifies the Sn4+ incorporation, Ba as Ba2+, O as O2– and Al as Al3+. Also, there is noticeable shift of O1s XPS peak towards lower B.E in Al doped sample which is indicative of dopants presence. FESEM studies shows that agglomerated nanoparticles were formed in pure BSO and Al doped samples it seems that Al doping further enhances the agglomeration and increases the average particle size from 300 nm to 600 nm. Uv–Vis studies shows that multiphase Al doped BSO is indirect band gap material for 2.4 eV and direct band gap at 3.3 eV while pure BSO has 2.6 eV as indirect and 2.9 as direct bandgap. Optical studies lead to the conclusion that with Al doped BSO is more transparent in the visible region than pure BSO whereas in pure BSO direct transitions are happening at 427 nm.

Nonlinear Absorption Features of Acid Blue 129 Dye in Polar Solvents: Role of Solvents on Solute Molecule.

This paper focuses the study of nonlinear absorption (NLA) features of anthraquinone dye namely, acid blue 129 with different polar solvents including ethanol, methanol, acetone, 1-proponal and DMSO. The acid blue 129 dye in polar solvents is characterized by UV-Visible absorption and fluorescence study. The NLA measurements of acid blue 129 dye is examined via open aperture (OA) Z-scan method employing at 650nm wavelength. The OA Z-scan curve of the experimental dye exhibits both saturable absorption (SA) and reveres saturable absorption (RSA) signature, which results from negative and positive NLA coefficient (β). The order of ground and excited state absorption cross-section is measured to be 10-22 m2 and 10-18 m2, respectively and proved the existence of RSA in acid blue 129 dye. The order of NLA coefficient and imaginary component of the third-order nonlinear susceptibility of acid blue 129 dye in polar solvents is calculated to be 10-3cm/W and 10-5 esu, respectively. The multi-parameter scale viz., Kamlet-Abboud-Taft is used to measure the influence of solvent parameters on solute molecule. The results from the experiments suggest that the acid blue 129 is a suitable candidate for nonlinear optical (NLO) applications.