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Polyvinylpyrrolidone (PVP)-based silver nanoprisms (AgNPrs) show an initial stacking geometry because of their low zeta potential and electrostatic interaction between face-to-face energetically stable {111} surface-bound pyrrolidone groups through the Na+-ion-induced cation−π interaction. Congested interplanar space between AgNPrs allows As(III) to react differentially with silver atoms from facial {111} and peripheral {110} facets to result in smaller stackings and finally nanoseeds. Above this critical concentration of As(III), PVP leached out from nanoparticles to form nanoseed-engulfed emulsions and induced controlled aggregation. This entire morphological transition has been decoded by recording their surface plasmon and surface-enhanced Raman scattering tuning and confirmed by the transmission electron microscopy study. Strong affinity and selectivity of As(III) toward the Ag atom (verified and estimated by the HF/3-21g* level of density functional theory calculation) coupled with low-cost colorime...

The role of the single-domain ferrimagnetic nanostructure and the associated surface for many fold magnetic-field-induced surface enhanced transient spin-trajectory modulation is a new venture in m...

Triplet-triplet (T-T) absorption spectroscopy has been used successfully as a molecular ruler to understand the actual release process of sanguinarine as a drug molecule from a gold nanoparticle surface in the presence of cell components, that is, DNA and chromatin. The obtained results have been verified by fluorescence and surface-enhanced Raman spectroscopy (SERS), and a plausible explanation has been put forward to describe the underestimation and overestimation of the percentage (%) of the release of drug molecules measured by fluorescence- and SERS-based techniques, respectively, over the highlighted T-T absorption spectroscopy. Because of the intrinsic nature of absorption, the reported T-T absorption spectroscopic assay overpowers fluorescence- and SERS-based assays, which are limited by the long-range interaction and nonlinear dependence of the concentration of analytes, respectively.

Kinetic Monte Carlo simulations for growth on substrates of three-fold symmetry predict the growth of islands of various shapes depending on the growth temperature [Phys. Rev. Lett. 71 (1993) 2967]. On Br–Si(1 1 1) substrates growth of epitaxial gold silicide islands of equilateral triangular and trapezoidal shapes have earlier been observed by annealing at the Au–Si eutectic temperature,363 � C [Phys. Rev. B 51 (1995) 14330]. We carried out annealing with temperature variation within a small window––(363 ± 30) � C. This has led to island growth of additional shapes like regular hexagon,elongated hexagon,walled hexagon and dendrite. Some of the observed island shapes have not been predicted.