Tuning Surface Plasmon in Erbium-Boro-Tellurite Nanoglass via Thermal Annealing

2016 ◽  
Vol 846 ◽  
pp. 85-90
Author(s):  
Zahra Ashur Mahraz ◽  
M.R. Sahar ◽  
S.K. Ghoshal
Keyword(s):  
Heat Treatment ◽  
Surface Plasmon ◽  
Average Diameter ◽  
Ir Absorption ◽  
Ag Nps ◽  
Absorption Bands ◽  
Time Duration ◽  
Maximum Enhancement ◽  
Silver Nps ◽  
Quenching Method

The demand for tunable surface plasmon (SP) of embedded metal nanoparticles (NPs) in rare earth doped inorganic lasing glasses is ever-growing. Following melt quenching method Er3+ doped zinc-boro-tellurite glasses containing silver (Ag) NPs are prepared. Glasses are heat treated (thermally annealed) at varying temperatures and time duration to alter the NPs morphology which generates SP. The annealing assisted SP resonance mediated modification in spectral features is discerned. Samples heat treatment at 410 °C for 6 hrs duration ensures the reduction of Ag+ ions to Ago NPs. Thermally annealed glasses are characterized via XRD, UV–Vis-IR absorption, photoluminescence spectroscopy, and TEM imaging. XRD spectra confirm the amorphous nature of the glass and TEM image reveals the existence of homogeneously distributed spherically shaped silver NPs of average diameter ~4.5 nm. NPs are found to grow with the increase of both annealing time and temperature. The UV–Vis spectra exhibit seven absorption bands corresponding to 4f–4f transitions of Er3+ ions in the wavelength range of 500-650 nm. The localized SPR band is evidenced at 550 and 580 nm. Heat treatment causes a red shift of the plasmon peaks ascribed to the alteration in glass refractive index. Furthermore, the glass sample annealed for 6 hrs displays maximum enhancement in the emission intensity corresponding to the peaks centered at 536 (2H11/2→4I15/2), 550 (4S3/2→4I15/2) and 632 nm (4F9/2→4I15/2). This enhancement is primarily attributed to the local field effect of the silver NPs. Admirable features of the results suggest that our systematic method for heat treatment in tuning NPs size assisted SPR may contribute towards the development of functional glass.

Silver Nanoparticles Included Er3+/Sm3+ Co-Doped Phosphate Glass: Evaluation of Thermal Stability and Infrared Absorption

2017 ◽  
Vol 268 ◽  
pp. 62-66 ◽  
Author(s):  
S. Rashidah Misron ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal
Keyword(s):  
Thermal Stability ◽  
Phosphate Glass ◽  
Infrared Absorption ◽  
Glass Network ◽  
Ir Absorption ◽  
Ag Nps ◽  
Bending Vibrations ◽  
Host Matrix ◽  
Stretching Vibrations ◽  
Quenching Method

Three lithium-sodium-phosphate glass samples with molar composition of (48.5–x)P2O5-20Na2O-30Li2O-0.5Sm2O3-1.0Er2O3-xAgNPs (where x = 0.01 g, 0.03 g and 0.05 g) are prepared using melt quenching method. The thermal stability and infrared absorption of synthesized samples are evaluated as a function of Ag NPs contents. Thermal and structural characterizations are made using differential thermal analysis (DTA) and Fourier transformed infrared (FTIR) spectroscopy, respectively. Thermal stability is found to vary in the range of 171 °C to 197 °C. FTIR spectra revealed various characteristic bonding vibrations related to the glass network structures. The IR absorption band around 570 cm-1 is assigned to the P-O-P bending vibrations while the occurrence of bands around 759 cm-1 and 913 cm-1 are allocated to the P-O-P symmetric stretching vibrations. The asymmetric stretching vibrations of (PO3)2- and (PO2)- units are observed around 1045 cm-1 and 1254 cm-1 , respectively. The appearance of a band around 1735 cm-1 is allocated to the free H2O molecules because of moisture attack to the sample. Influences of Ag NPs in the host matrix are analyzed and explained.

scholarly journals Surface Plasmon Resonance Enhanced Spontaneous Upconversion and Stimulated Emissions in Glass Ceramics Containing Ba2LaF7 Nanocrystals

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Sai Li ◽  
Wei Lu ◽  
Qihua Yang ◽  
Dacheng Zhou ◽  
Jianbei Qiu ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Glass Ceramic ◽  
Visible Region ◽  
Glass Ceramics ◽  
Random Lasing ◽  
Ag Nps ◽  
The Matrix ◽  
Quenching Method

Glass ceramics containing Yb3+, Er3+ codoped Ba2LaF7 nanocrystals were fabricated via melt quenching method and the subsequent heating treatment. The formation of Ba2LaF7 nanocrystals in the glass ceramics was confirmed by X-ray diffraction (XRD) and transmission electron microscope (TEM). The spontaneous upconversion (UC) emission and the stimulated counterpart as a random lasing action of Er3+, which were related to the characteristic transitions of Er3+ ions, were achieved in the Yb3+, Er3+-doped Ba2LaF7 nanocrystals embedded glass ceramic hybrid. Furthermore, the absorption spectra verified the surface plasmon resonance (SPR) band of Ag, which precipitated from the matrix glasses as Ag nanoparticles (NPs). By incorporating Ag NPs in the glass ceramic hybrid, spontaneous UC emission intensity of Er3+ in visible region was significantly enhanced, while the threshold of the random lasing was decreased from 480 to 350 nJ/cm2.

Study of Tb-doped Li2O-LaF3-Al2O3-SiO2 Glasses Containing Silver Nanoparticles

2009 ◽  
Vol 1208 ◽  
Author(s):  
Zhengda Pan ◽  
A Crosby ◽  
O Obadina ◽  
A. Ueda ◽  
R. Aga ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Silver Nanoparticles ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Excitation Spectra ◽  
Radiative Relaxation ◽  
Broad Absorption Band ◽  
Quenching Effect ◽  
Competitive Effects ◽  
Silver Nps

AbstractTb-doped Li2O-LaF3-Al2O3-SiO2 (LLAS) glasses containing silver were fabricated using melt-quenching technique. Silver nanoparticles (NPs) in glass matrix were confirmed by optical absorption and X-ray diffraction (XRD). The nucleation of silver NPs was controlled by heat-treatment. A broad absorption band peaked at about 420 nm was observed due to surface plasmon resonance (SPR) of the silver NPs. This SPR absorption of silver NPs increases with the time of heat-treatment. Photoluminescence (PL) emission and excitation spectra were measured on Tb-doped LLAS glasses with and without silver NPs. Strong Tb3+ luminescence was observed. For excitation at 325 nm, luminescence of Tb3+ ions increases for the glass containing silver NPs compared to that in the glass without silver NPs. After further heat-treatment at 520 °C for 5 hours, Tb3+ luminescence decreased. Our luminescence results suggest that there are two competitive effects, enhancement and quenching effects, acting on Tb3+ luminescence in the glass containing silver NPs. The enhancement of Tb3+ luminescence is attributed to local field effects due to the excitation of SPR of silver NPs. The quenching effect in the presence of Ag NPs suggests an energy transfer from Tb3+ ions to silver NPs exists, which may provide an additional non-radiative relaxation pathway for the excited Tb3+ ions.

Nevirapine Pharmaceutical Cocrystal: Design, Development and Formulation

2019 ◽  
Vol 9 (3) ◽  
pp. 240-247
Author(s):  
Prabhakar Panzade ◽  
Priyanka Somani ◽  
Pavan Rathi
Keyword(s):  
Dosage Form ◽  
In Vitro Dissolution ◽  
Soluble Form ◽  
Ir Absorption ◽  
Stoichiometric Ratio ◽  
Design Development ◽  
Formulation Development ◽  
Scanning Calorimetry ◽  
Absorption Bands ◽  
Pharmaceutical Cocrystal

Background and Objective: The top approach to deliver poorly soluble drugs is the use of a highly soluble form. The present study was conducted to enhance the solubility and dissolution of a poorly aqueous soluble drug nevirapine via a pharmaceutical cocrystal. Another objective of the study was to check the potential of the nevirapine cocrystal in the dosage form. Methods: A neat and liquid assisted grinding method was employed to prepare nevirapine cocrystals in a 1:1 and 1:2 stoichiometric ratio of drug:coformer by screening various coformers. The prepared cocrystals were preliminary investigated for melting point and saturation solubility. The selected cocrystal was further confirmed by Infrared Spectroscopy (IR), Differential Scanning Calorimetry (DSC), and Xray Powder Diffraction (XRPD). Further, the cocrystal was subjected to in vitro dissolution study and formulation development. Results: The cocrystal of Nevirapine (NVP) with Para-Amino Benzoic Acid (PABA) coformer prepared by neat grinding in 1:2 ratio exhibited greater solubility. The shifts in IR absorption bands, alterations in DSC thermogram, and distinct XRPD pattern showed the formation of the NVP-PABA cocrystal. Dissolution of NVP-PABA cocrystal enhanced by 38% in 0.1N HCl. Immediate release tablets of NVP-PABA cocrystal exhibited better drug release and less disintegration time. Conclusion: A remarkable increase in the solubility and dissolution of NVP was obtained through the cocrystal with PABA. The cocrystal also showed great potential in the dosage form which may provide future direction for other drugs.

scholarly journals Effect of Solvent Refractive Index on the Surface Plasmon Resonance Nanoparticle Optical Absorption

2007 ◽  
Vol 7 (12) ◽  
pp. 4333-4338
Author(s):  
Gulay Ertas ◽  
Sefik Suzer
Keyword(s):  
Gold Nanoparticles ◽  
Refractive Index ◽  
Surface Plasmon ◽  
Surrounding Medium ◽  
Point Of View ◽  
Experimental Point ◽  
Absorption Bands ◽  
Plasmon Band ◽  
Silver And Gold Nanoparticles ◽  
Band Position

Optical properties of plasmon coupled silver and gold nanoparticles were studied as a function of the refractive index of the surrounding medium. Our studies confirmed that the effect of changes in the refractive index of the surrounding medium was more difficult to demonstrate from an experimental point of view, because of the very high susceptibility of nanoparticles to aggregate in aqueous and organic solvents. Whereas the position of the absorption bands of triiodide in these solvents shows a clear dependence on medium's refractive index, the surface plasmon band position of silver and gold nanoparticles do not exhibit the same dependence. This is attributed to a non-negligible interaction of these solvents with nanoparticle surfaces.

scholarly journals Green Synthesis of Silver Nanoparticles Using Raw Fruit Extract of Mimusops elengi and their Antimicrobial Study

2020 ◽  
Vol 11 (3) ◽  
pp. 10040-10051
Keyword(s):  
Green Synthesis ◽  
Colloidal Stability ◽  
Low Cost ◽  
Antimicrobial Activities ◽  
Health Food ◽  
Ag Nps ◽  
Fruit Extract ◽  
Silver Nps ◽  
Mimusops Elengi ◽  
Bacteria And Fungi

These days, nanoparticles are being considered as nano-antibiotics because of their execution of antimicrobial activities towards a broad range of microbes. Nanoparticles are used in industrial products, health, food, space, and cosmetics;thus, researchers need for a green, ecofriendly, and low-cost approach to synthesize it. Green synthesis is such an approach of synthesizing NPs using microorganisms and plants, which is free of additional impurities. We used Mimusops elengi Linn. raw fruit extract in water to reduce the silver nitrate salt to produce silver NPs. The samples were characterized using various instrumental techniques. Broadband known as Surface Plasmon Resonance found near 450 nm in the absorption spectrum shows the formation of Ag NPs. NPs with average hydrodynamic diameters in the ranges 20-300 nm were detected from DLS study having negative zeta potential value (varies between - 25.8 to 15.8 mV), which suggests that as NPs surface is charged, it provides colloidal stability to the NPs in a liquid medium. FTIR study reveals that an increase in the intensity of some of the vibrational band with NP-content is due to the adsorption of some molecules on the surface of NPs. XRD pattern shows that NPs have an fcc structure. Samples were tested to have capabilities to kill both bacteria and fungi.

scholarly journals Изотопные эффекты в спектрах комплексов с водородными связями. Ангармонические расчеты изотопологов комплекса [F(HF)-=SUB=-2-=/SUB=-]-=SUP=---=/SUP=-

2020 ◽  
Vol 128 (8) ◽  
pp. 1077
Author(s):  
В.П. Булычев ◽  
М.В. Бутурлимова ◽  
К.Г. Тохадзе
Keyword(s):  
Basis Set ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Spectral Parameters ◽  
Basis Set Superposition Error ◽  
Band Frequency ◽  
Normal Vibrations ◽  
K Meson ◽  
Anharmonic Interactions ◽  
Good Agreement

The frequencies and intensities of IR absorption bands of symmetric and asymmetric H-bonded complexes [FL1FL2F]- (L1, L2 = K-meson Ka, proton H, deuton D, and triton T) are calculated. The equilibrium configuration and potential energy and dipole moment surfaces of isotopologues [FL1FL2F]- were calculated by the MP2/6-311++G(3df,3pd) method with the basis set superposition error taken into account. The calculations of spectral parameters with allowance for anharmonic interactions of all vibrations were carried out using the second-order vibrational perturbation theory. Variation of Li and L2 masses in wide regions allowed significant changes in the forms of normal vibrations and values of anharmonic interaction constants upon isotopic substitution to be obtained. The trends in the changes of spectral parameters were determined upon transition from one symmetric isotopologue to another and upon transition from symmetric to asymmetric isotopologues. The D-F stretching band frequency predicted for [FHFDF]- is in good agreement with the experimental value. The assignment of this band was improved.

scholarly journals Local vibrational modes of vacancy-oxygen-related complexes at room temperature

2020 ◽  
Vol 56 (4) ◽  
pp. 480-487
Author(s):  
E. A. Tolkacheva ◽  
V. P. Markevich ◽  
L. I. Murin
Keyword(s):  
Absorption Band ◽  
Room Temperature ◽  
Clear Correlation ◽  
Ir Absorption ◽  
Oxygen Impurity ◽  
Interstitial Oxygen ◽  
Vibrational Modes ◽  
Oxygen Defect ◽  
Absorption Bands ◽  
Local Vibrational Modes

The isotopic content of natural silicon (28Si (92.23 %), 29Si (4.68 %) и 30Si (3.09 %)) affects noticeably the shape of IR absorption bands related to the oxygen impurity atoms. In the present work an attempt is undertaken to determine the positions of local vibrational modes (LVMs), related to quasimolecules 28Si16OS29Si and 28Si16OS30Si (OS – substitutional oxygen atom), for the absorption spectra measured at room temperature. An estimation of the isotopic shifts of corresponding modes is done by fitting the shape of the experimentally measured absorption band related to the vacancy–oxygen center in irradiated Si crystals. The LVM isotope shifts are found to be equal 2,2 ± 0.25 cm–1 for 28Si-16OS29Si and 4,3 ± 0,9 см–1 for 28Si-16OS30Si in relation to the basic band due to 28Si-16OS28Si, and the full width at half maximum of the A-center absorption band (28Si-16OS28Si) is 5,3 ± 0.25 cm–1. By means of infrared absorption spectroscopy a clear correlation between the disappearance of the divacancy (V2) in the temperature range 200–275 ºС and appearance of two absorption bands with their maxima at 825.8 and 839.2 cm–1 in irradiated oxygen-rich Si crystals is found. The band positioned at 825.8 cm–1 is assigned to a divacancy-oxygen defect V2O formed via an interaction of mobile V2 with interstitial oxygen (Oi ) atoms. The 839.2 cm–1 band is much more pronounced in neutron irradiated samples as compared to samples irradiated with electrons. We argue that it is related to a trivacancy–oxygen defect (V3O) formed via an interaction of mobile V3 with Oi atoms.

Magneto-Chemical Properties of Some New Ni and Co Rare-Earth Metal Tungstates

2007 ◽  
Vol 128 ◽  
pp. 207-212 ◽  
Author(s):  
Adam Worsztynowicz ◽  
Slawomir M. Kaczmarek ◽  
Elzbieta Tomaszewicz
Keyword(s):  
Rare Earth ◽  
Rare Earth Metal ◽  
Epr Spectroscopy ◽  
Chemical Properties ◽  
Earth Metal ◽  
Temperature Evolution ◽  
Ir Absorption ◽  
Absorption Bands ◽  
Metal Tungstates

New d-electron and rare-earth metal tungstates (CoRE2W2O10; CoRE4W3O16; Co2RE2W3O14 and NiRE2W2O10) were studied by the IR and EPR spectroscopy methods. The IR absorption bands with their maxima can be assigned to the symmetric and asymmetric stretching modes of W-O bonds in the joint of WO6 octahedra and also to the oxygen double WOOW bridge bonds. The wide, unstructured EPR powder spectra of these compounds and their temperature evolution have been analyzed and interpreted.

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