Publications

Hybrid materials comprising diamond nanoparticles (ND) and oligo(phenylenevinylenes) (OPVs) have been synthesized by the covalent linking of acid-functionalized ND and OPV-amine. Chromophore-functionalized ND particles with long alkyl and π-conjugated groups are readily dispersed in various organic solvents without any precipitation after several hours. A careful study of the properties of the hybrid materials revealed an aggregation-induced energy transfer from the blue fluorescent nanodiamonds to green emitting OPVs. At very low concentrations the hybrid emits in the blue region, but as the concentration is increased a gradual transition from blue to green emission occurs. Competitive processes such as aggregation-induced enhanced emission and self-absorption have been ruled out and a molecular picture of the phenomenon is proposed. This strategy can open a plethora of new avenues for fluorescent nanodiamonds in optoelectronics and light harvesting apart from bio-imaging.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

BiAlO3, prepared under high-pressure and high-temperature conditions has a rhombohedral perovskite structure ( R 3 c with a = 5.3747 ( 4 )  Å and c = 13.391 ( 1 )  Å) and decomposes around 550 ∘C to form the intermediate Bi2Al4O9 phase along with the Bi 26 − x Al x O 40 − y and Al2O3. Above 580 ∘C, the intermediate phase changes into the Bi 26 − x Al x O 40 − y . Dielectric measurements show an anomaly at the decomposition temperature and hysteresis at room temperature with a maximum polarization of ∼16 μC/cm2. Raman scattering measurements suggest softening of optical phonon modes, and are consistent with the occurrence of thermal decomposition of the rhombohedral phase to form the thermodynamically stable phase.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

We report the first electron paramagnetic resonance studies of single crystals and powders of Pr0.6Ca0.4MnO3 in the 300-4.2 K range, covering the charge-ordering transition (Tco) at ~240 K and antiferromagnetic transition (TN) at ~170 K. The asymmetry parameter for the Dysonian single-crystal spectra shows an anomalous increase at Tco. Below Tco the g-value increases continuously, suggesting a gradual strengthening of the orbital ordering. The linewidth undergoes a sudden increase at Tco and continues to increase down to TN. The intensity increases as the temperature is decreased until Tco is reached, due to the renormalization of the magnetic susceptibility arising from the build-up of ferromagnetic correlations.

Considering the important role played by surface functionalities, we have obtained quantitative estimates of the functionalities on graphene, BN and borocarbonitrides, by employing fluorescence labeling. Thus, the surface concentrations of carbonyl, carboxylic and hydroxyl groups on the graphene surface are 2.31×1020, 28.17×1020 and 0.08×1020 per gram respectively. We do not observe carbonyl groups on reduced graphene oxide. The surface concentration of the amine group on BN is 0.01×1020 per gram. Borocarbonitrides contain amine and oxygen functionalities, with composition dependent concentrations. Supercapacitor performance and ORR activity of the borocarbonitrides are presented along with their surface areas.

Mossbauer and electrical resistivity measurements on Eu 1−x Sr x FeO 3 (0.0 T N . Variable range hopping arising from Anderson localization seems to occur at T N indicating that the electron hopping time in this regime is likely to be greater than 10 −7 s. Mossbauer studies on Nd 1−x Sr x CoO 3 show that in the Anderson localization regime, the hopping time is greater than 10 −7 s in this system as well.

Membrane-based technology is emerging as an efficient technique for wastewater treatment in recent years. Membranes made up of two-dimensional materials provide high selectivity and water flux compared to conventional polymeric membranes. Herein, we report the synthesis and use of MoSe2 membrane for dye and drug separation in wastewater, mainly from textile and pharmaceutical industries. The as-prepared MoSe2 membrane shows ∼ 100% rejection for organic dyes and ciprofloxacin drug with a water flux reaching up to ∼ 900 Lm-2h-1bar-1. Further, the MoSe2 membrane shows lower NaCl rejection of ∼ 1.9% for the dye/salt mixture. The interlayer spacing in the MoSe2 membrane allows the water molecules and ions from the salt to pass through freely but restricts the movement of large contaminants. The membrane is stable against the bovine albumin serum fouling with a flux recovery rate of 96%. It also shows good performance even in harsh environments (pH 3–10). To the best of our knowledge, the MoSe2 membranes were fabricated for the first time for wastewater treatment application. The dye/salt separation performance of the MoSe2 membrane is significantly better than several other membranes. This work highlights the promising potential for using two-dimensional materials for textile and pharmaceutical wastewater treatment.

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