[en] One electron reduction of 1,2 dihydroxy 9,10 anthraquinone and its Cu(II) and Ni(II) and Fe(III) complexes have been studied in aqueous-isopropanol-acetone solvent. Results indicate that the reducing ketyl radical generated reacts with the ligand forming semiquinones which undergoes a disproportionation reaction. Formation and decay rates of semiquinones was calculated using pulse radiolysis. (author)

[en] CdSe quantum dots (QDs) were synthesized by a rapid and one step templated approach inside the water pool of AOT (sodium bis(2-ethylhexyl) sulfosuccinate) based water-in-oil microemulsions (MEs) via electron beam (EB) irradiation technique with high dose rate, which favours high nucleation rate. The interplay of different experimental parameters such as precursor concentration, absorbed dose and ${\mathcal{W}}_0$ values (aqueous phase to surfactant molar ratio) of MEs were found to have interesting consequences on the morphology, photoluminescence (PL), surface composition and carrier recombination dynamics of as-grown QDs. For instance, highly stable ultrasmall (∼1.7 nm) bluish-white light emitting QDs were obtained with quantum efficiency (η) of ∼9%. Furthermore, QDs were found to exhibit tunable broadband light emission extending from 450 to 750 nm (maximum FWHM ∼180 nm). This could be realized from the CIE (Commission Internationale d’Eclairage) chromaticity co-ordinates, which varied across the blue region to the orange region thereby, conferring their potential application in white light emitting diodes. Additionally, the average PL lifetime $(⟨\mathrm{\tau <!--\; ??\; -->}⟩)$ values could be varied from 18 ns to as high as 74 ns, which reflect the role of surface states in terms of their density and distribution. Another interesting revelation was the self-assembling of the initially formed QDs into nanorods with high aspect ratios ranging from 7 to 20, in correspondence with the ${\mathcal{W}}_0$ values. Besides, the fundamental roles of the chemical nature of water pool and the interfacial fluidity of AOT MEs in influencing the photophysical properties of QDs were investigated by carrying out a similar study in CTAB (cetyltrimethylammonium bromide; cationic surfactant) based MEs. Surprisingly, very profound and contrasting results were observed wherein $⟨\mathrm{\tau <!--\; ??\; -->}⟩$ and η of the QDs in case of CTAB MEs were found to be at least three times lower as compared to that in AOT MEs. (paper)

[en] One-electron oxidation of 1,2-dihydroxy 9,10 anthraquinone and its Cu(II) and Ni(II) complexes by OH^. and N₃^. radicals have been studied. Both the radicals react with the compounds forming semi-oxidised quinone radical. The semi-oxidised radicals formed in free quinone undergo disproportionation reaction, whereas those in metal complexes give rise to oxidation of the metal complexes leading to partial destruction of the ligand. (author)

[en] Silicon (Si) has received a great deal of attention in the field of nanoscience and nanotechnology over the past three decades due to its excellent biocompatibility, natural abundance and cost-effectiveness. Considering the imminent importance of Si nanomaterials (NMs) in various areas, a highly rapid, eco-friendly, and one-pot scalable approach based on radiation-induced technique is being reported for their preparation. In order to tune the photoluminescence (PL) properties, different metal ions were doped into SiONCs. For instance, on doping with Mn²⁺ ions, the PL of SiONCs exhibited tunability from blue to green region. This is an indication of the tetrahedrally coordinated Mn²⁺ ions in the matrix of SiONCs. In addition to this, lanthanides such as Eu³⁺ and Tb³⁺ were doped into SiONCs, which resulted in significant changes in their PL properties. The as obtained doped SiONCs were explored for the sensing of toxic metal ions. Detailed analysis and the possible sensing mechanism will be discussed