K. S. Gour; A. K. Yadav; Rahul Kumar; J. S. Tawale; V. N. Singh
Abstract
Zinc oxysulfide or Zn(O,S) is emerging as an alternate n-type buffer layer for kesterite, chalcogenides and CdTe based thin film solar cell due to it is being made from non-toxic elements and tunable bandgap, its suitable optical and electrical properties required for a buffer layer. Generally, buffer ...
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Zinc oxysulfide or Zn(O,S) is emerging as an alternate n-type buffer layer for kesterite, chalcogenides and CdTe based thin film solar cell due to it is being made from non-toxic elements and tunable bandgap, its suitable optical and electrical properties required for a buffer layer. Generally, buffer layers of these solar cells are deposited using chemical bath deposition (CBD) techniques, but these require breaking of vacuum and again inserting the sample in vacuum during solar cell fabrication, which is not economical and is cumbersome. Sputtering is considered to be industrial process and therefore, here we have deposited Zn(O,S) thin film by sputtering technique and effect of sulfurization temperature on bandgap and composition of Zn(O,S) films have been studied. The bandgap of deposited films changed from 3.36 eV to 3.15 eV by changing the sulfurization temperatures. By changing the sulfurization temperature, the composition of films also changed. Crystallite size (D) of Zn(O,S) films increased from 12.1 nm to 22.3 nm by varying the sulfur content for samples S1-S4, respectively. Optical, morphological, compositional and structural properties have been studied using UV-Vis-NIR spectroscopy, Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) and X-ray diffractometer (XRD), respectively.
Swarup Roy; K.C. Majumdar;Tapan Kumar Das; Sudipta Ponra; Tapas Ghosh
Abstract
Study of interaction between synthetic spiropyrimidines (SP) with bovine serum albumin (BSA) was investigated by spectroscopy. The fluorescence of BSA was quenched by SP by means of static quenching mechanism. Using Stern–Volmer analysis of the fluorescence quenching data number of binding sites ...
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Study of interaction between synthetic spiropyrimidines (SP) with bovine serum albumin (BSA) was investigated by spectroscopy. The fluorescence of BSA was quenched by SP by means of static quenching mechanism. Using Stern–Volmer analysis of the fluorescence quenching data number of binding sites (n) and binding constants (K) at different temperatures were computed. The thermodynamic parameters enthalpy change (ΔH) and entropy change (ΔS) were calculated using Van’t Hoff equation (ΔH = -95.16 kJ/mol and ΔS = -251.49 J/mol/ K) and the results clearly indicated binding process is enthalpy-driven but entropically disfavored. The weak force van der Waals interaction and hydrogen bonding is responsible for BSA-SP complexation. Synchronous fluorescence, UV-Vis and circular dichroism (CD) spectra proposed possibility of alteration in conformation of BSA in the presence of SP. Using Forster’s non-radiation energy transfer (FRET) theory distance between the donor and the acceptor were found to be <7 nm.
Swarup Roy; Sudipta Ponra; Raj Kumar Nandi; K. C. Majumdar; Tapan Kumar Das
Abstract
The study of interaction between spirooxindole-annulated thiopyran derivatives (STP) and bovine serum albumin (BSA) was investigated using multi-spectroscopic and docking method. The intrinsic fluorescence of BSA could effectively quenched by STP through dynamic quenching. The thermodynamic parameters ...
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The study of interaction between spirooxindole-annulated thiopyran derivatives (STP) and bovine serum albumin (BSA) was investigated using multi-spectroscopic and docking method. The intrinsic fluorescence of BSA could effectively quenched by STP through dynamic quenching. The thermodynamic parameters suggested that hydrogen bonds and van der Waals forces played a key role in stabilizing the BSA–STP complexes. According to Forster non radiation energy transfer theory (FRET) the average binding distance (r) between STP and BSA were found to be < 7 nm. Furthermore, UV-visible and circular dichroism results indicated that in presence of STP secondary structure of BSA changed. Theoretical docking study of the interaction of BSA and STP also supported the experimental results.
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