In this work, we report manifested optical, optoelectronic and spin–spin relaxation features of a few layered tungsten disulphide (WS2) nanosheets subjected to energetic γ-photons (∼1.3 MeV) emitted from a Co60 source. Upon intense irradiation (dose = 96 kGy), a slight departure from the pure hexagonal phase was realized with the introduction of the trigonal phase at large. Moreover, in the Raman spectra, as a consequence of the radiation-induced effect, an apparent improvement of the E-to-A mode intensity and a reduction in phonon lifetimes have been realized, with the latter being dependent on the linewidths. The emergence of the new peak (D) maxima observable at ∼406 cm−1 in the Raman spectra and ∼680 nm in the photoluminescence (PL) spectra can be attributed to the introduction of defect centres owing to realization of sulphur vacancies (V S) in the irradiated nanoscale WS2. Additionally, neutral exciton to charged exciton (trion) conversion is anticipated in the overall PL characteristics. The PL decay dynamics, while following bi-exponential trends, have revealed ample improvement in both the fast parameter (0.39 ± 0.01 ns to 1.88 ± 0.03 ns) and the slow parameter (2.36 ± 0.03 ns to 12.1 ± 0.4 ns) after γ-impact. We attribute this to the finite band gap expansion and the incorporation of new localized states within the gap, respectively. A declining exciton annihilation rate is also witnessed. The isotropic nature of the electron paramagnetic resonance spectra as a consequence of γ-exposure would essentially characterize a uniform distribution of the paramagnetic species in the system, while predicting a three-fold improvement of relative spin density at 96 kGy. Exploring defect dynamics and spin dynamics in 2D nanoscale systems does not only strengthen fundamental insight but can also offer ample scope for designing suitable components in the areas of miniaturized optoelectronic and spintronic devices.

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We report on the effect of 80 keV Xe + ion irradiation on the commercially available, sectioned 10B pencil-graphite specimens subjected to normal and oblique angle incidence of ions (θi = 0 • -70 • ) and considering a fixed ion fluence of 1 × 10 14 ions/cm 2 . The pristine and irradiated samples were characterized by powder x-ray diffraction, atomic force microscopy and Raman spectroscopy studies. Unlike pristine graphite and normal incidence cases, several ripple patterns can be visualized in the atomic force micrographs of the specimens irradiated with an oblique angle incidence. Moreover, apart from conventional G-band located at ∼1580 cm −1 , a distinct diamond-like carbon (DLC) phase has been witnessed at ∼1330 cm −1 in the Raman spectra of the graphitic specimens subjected to ion impact and for θi values of 50 • and 70 • . The formation of the DLC phase along with surface ripple formation would find numerous scopes while dealing with properties such as surface transport, field emission and mechanically hard coating in miniaturized devices.

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This report describes a comparative study of dye degradation under 20-watt LED light using the perovskite photocatalyst Calcium Copper Titanate (CCTO) and its compositions (CaxCu3-xTi4O12) (x=1, 1.5 and 2), synthesized by changing molar ratios of Ca 2+ and Cu 2+ ions. The 99.74% degradation of Rhodamine Blue (RhB) with composition (x=1) within 6 h is reflected its better photocatalytic activity than the parent CCTO and other compositions. The band gap energy of the materials 2.18 eV (CCTO), 1.93 eV (x=1), 2.40 eV (x=1.5), and 2.55 eV (x=2) are analysed with UV-Vis spectroscopy. The presences of Ca, Cu, Ti and O in the synthesized photocatalysts are confirmed with Elemental X-ray Dispersive (EDX) analysis. The cubic phases in the polyhedral shape of the materials are detected in Xray diffraction and Scanning Electron Microscopy (SEM). This report further observes the defect density concentrations of the materials with Photoluminescence Spectroscopy (PL) and provides the approximate explanation of their dye degradation performance as photocatalysts.The rate constants are found in a first order reaction trend; where the composition (x=1)shows about 1.683×10 -2 min -1 . The mechanistic understanding of the degradation process is also revisited and rationalized with different scavengers for the process.