Supratim Basak

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.

Passive optical waveguiding organic rectangular tubes: tube cutting, controlling light propagation distance and multiple optical out-puts

We propose a technique to precisely control the longitudinal dimension of self-assembled organic nanotubes to obtain tailor-made lengths using laser ablation or cutting. Since these organic nanotubes show passive optical waveguiding tendency, the presented cutting technique is quite useful to exactly control the light propagation distance and to create multiple optical outputs. The guiding efficiency of a tube is dependent on its wall thickness, lengths and defect density. A tube not in contact with the substrate also guides the optical wave indicating its true waveguiding nature.

Lithographically organized 1D nano-tape arrays composed of solution processable above room temperature spin cross-over Fe(II) coordination polymer

A novel, highly soluble and solution processable Fe(II) spin cross-over (SCO) coordination polymer shows an SCO temperature at T1/2 ∼ 302 K. Bottom-up self-assembly of this supramolecular polymer in THF–water formed a several micron long nano-tape network. Further solution processing using a lithographically controlled wetting technique produced aligned 1D arrays of SCO nano-tape bundles.

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.

Optical Waveguiding Organic Nanorods Coated with Reversibly Switchable Fe(II) Spin Transition Nanoparticles

A dual functional nanohybrid object combining photonic and magnetic properties was successfully prepared through a “bottom-up” self-assembly approach. In this method, spin transition Fe(II) coordination nanoparticles and optical wave guiding organic nanorods were generated in situ and successfully integrated together in a single pot through self-assembly. The Fe(II) nanoparticles coated on organic nanorods (nanohybrids) display temperature dependent reversible spin transition (Paramagnetic; diamagnetic; ) behavior. The nano-hybrids show efficient optical wave guiding behavior, which demonstrates the future possibility to perform light induced excited spin state trapping (LIESST) experiments on a single spin transition nanoparticle level. These photonic and magnetic “nanohybrids” offer promising option to externally manipulate spin state of the spin transition nanoparticles using temperature as well as remote laser light.

Hierarchical lithographic patterning of two abrupt spin cross-over Fe(II) complexes into micro-cross-stripes

We have fabricated high-resolution microscale cross-patterns from two different Fe(II) spin crossover (SCO) complexes having transition temperatures (

White-Emitting Conjugated Polymer/Inorganic Hybrid Spheres: Phenylethynyl and 2,6-Bis(pyrazolyl)pyridine Copolymer Coordinated to Eu(tta)3

T_{1/2}

Micropatterning of metallopolymers: syntheses of back-to-back coupled octylated 2,6-bis(pyrazolyl)pyridine ligands and their solution-processable coordination polymers.

T1/2) 259 K and 323 K, through lithographic techniques. We hope that our original approach will be useful to create futuristic multi-component SCO devices.GRAPHICAL ABSTRACTSYNOPSIS High-resolution micro-scale cross-patterns from two different Fe(II) spin cross-over (SCO) complexes having transition temperatures (