Naisa Chandrasekhar

Reversibly Shape‐Shifting Organic Optical Waveguides: Formation of Organic Nanorings, Nanotubes, and Nanosheets

because the functions of thenanoobjects are dependent on their shape and dimensions. Inthe area of organic nanophotonics in particular, the confine-ment of optical waves in shape-shifting organic nanostruc-tures is interesting because of their potential use in “smart”nanooptical devices, such as optical waveguides, photonicdetectors, and optical sensors.Until now, no methods for the fabrication of reversiblyshape-shifting organic nanostructures that have dimension-ally dependent optical waveguiding properties have beenavailable. Most of the reported organic waveguides havedefined shapes

Planar Active Organic Waveguide and Wavelength Filter: Self-Assembled meso-Tetratolylporphyrin Hexagonal Nanosheet

We have fabricated nearly monodispersed nanocrystalline sheet waveguides from a well-known red emitting meso-tetratolylporphyrin molecule (1) by following a bottom-up solvent assisted self-assembly technique. The nano-sheets thickness is in the range of 110-180 nm. Localized laser illumination showed excitation position dependent exciton polariton (653 and 719 nm) propagation behavior of the sheets. The spatially resolved fluorescence spectra of the sheets showed optical modes at the input and output points, indicating cavity effect. Additionally, because of the reabsorption of the 653 nm emission, the nanosheets also act as wave length filter by cutting off the 653 nm photons from reaching the output end.

Fabrication of High‐Resolution 4,82‐Type Archimedean Nanolattices Composed of Solution Processable Spin Cross‐Over Fe(II) Metallosupramolecular Polymers

This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers with two counter anions from a novel back-to-back coupled hybrid ligand. The spin cross-over (SCO) temperature of polymers with BF4 and ClO4 counter anions is T1/2 = 313 K and T1/2 = 326 K, respectively. By following the top-down approach, one of the polymers (with ClO4 counter anion) is successfully solution processed using a lithographically controlled wetting technique to create laser readable high-resolution Archimedean (4,8(2) ) nanolattices (consist of diamagnetic octagons and SCO squares). The thickness and top area of each SCO square are ≈75 nm and ≈2 × 2 μm(2) , respectively.

Passive optical waveguiding tubular pharmaceutical solids and Raman spectroscopy/mapping of nano-/micro-scale defects

Self-assembled one dimensional pharmaceutical solids composed of caffeine, carbamazepine and glibenclamide drugs exhibit optical waveguiding tendency due to the efficient two dimensional lateral optical confinement effect. Additionally, the confined optical waves within the tubes were used to probe the nano-/micro-scale defect sites inherited during the tube self-assembly process via Raman spectroscopy.