Uppari Ramudu | University Of Hydrabad (original) (raw)

Papers by Uppari Ramudu

Advanced Optical Materials, Nov 28, 2022

An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more 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.

Journal of Chemical Sciences, 2018

We have fabricated high-resolution microscale cross-patterns from two different Fe(II) spin cross... more We have fabricated high-resolution microscale cross-patterns from two different Fe(II) spin crossover (SCO) complexes having transition temperatures (T 1/2) 259 K and 323 K, through lithographic techniques. We hope that our original approach will be useful to create futuristic multi-component SCO devices.

Crystal Growth & Design, 2018

characterized by PXRD, IR spectroscopy, CHNS and thermogravimetric (TG) analysis. Finally, all th... more characterized by PXRD, IR spectroscopy, CHNS and thermogravimetric (TG) analysis. Finally, all three compounds are characterized unambiguously by single crystal X-ray diffraction analysis. We have demonstrated, the compound {Co(bppCOO)(HCOO)(H 2 O)} n • n1.5H O (3), having Co(II) coordinated water has potential in exhibiting electrocatalytic water oxidation at a neutral pH.

ACS Applied Energy Materials, 2018

Optical green emitting microresonators with high values of nonlinearity are desired for high opti... more Optical green emitting microresonators with high values of nonlinearity are desired for high optical up-conversion energy storage and lasing applications. Here we report on the synthesis of benzylammonium lead iodide (BALI) perovskite microcrystals made via anti-solvent diffusion

Journal of Materials Chemistry C, 2017

C-153 dye, upon self-assembly in mixed acetonitrile and water solvents formed polymorphic tubes, ... more C-153 dye, upon self-assembly in mixed acetonitrile and water solvents formed polymorphic tubes, rods, sheets and Japanese twin tubes displaying molecular packing dependent diverse emission colours and a shape-dependent optical cavity effect.

Physical chemistry chemical physics : PCCP, Jan 21, 2016

Self-assembled hexagonal organic submicrotubes, upon electronic excitation with an UV laser, disp... more Self-assembled hexagonal organic submicrotubes, upon electronic excitation with an UV laser, display an active type polarized whispering gallery mode (WGM) resonance in the visible (Vis) range (400-600 nm). Due to the photonic cavity effect the tubes show fluorescence (FL) signal intensity 5× greater than the corresponding powder state. Furthermore, the same tubes, which are passive to a visible laser, produce yellow-orange emitting carbonaceous lumps when burnt with an intense laser beam (42 mW) forming a chemically binary heterogeneous structure. The hetero-structure upon excitation with a visible laser at the passive tubular part showed emission in the Vis-Near infrared (NIR) range (500-800 nm) with WGMs thus producing a passive/active type hetero-structure photonic resonator.

The spin cross-over (SCO) phenomenon is a reversible magnetic switching between low-spin (LS) and... more The spin cross-over (SCO) phenomenon is a reversible magnetic switching between low-spin (LS) and high-spin (HS) states due to the modulation of ligand field strengths depending on the temperature, light and pressure. The molecular bistability of SCO molecules is associated with a lack of fatigue; there is considerable interest for applications such as sensors and digital memory. Fabrication of a novel spin cross-over coordination polymer was successfully achieved by top-down approach (2-D Lithography). The Fe(II) SCO coordination polymers were synthesized from novel 1,4-bis(2-(1-butyl-1H-1,2,3-triazol-4-yl)-6-(1H-pyrazol-1-yl)pyridin-4-yl)benzene (L1-L3) ligands. Similarly using the top-down approach we are able to form woodpile structure comprised with a blue emitting polymer and the Eu and Tb complexed analogue of the polymer.

Physical Review B, 2005

Polarized second-harmonic generation and terahertz radiation in reflection from ͑100͒, ͑110͒, and... more Polarized second-harmonic generation and terahertz radiation in reflection from ͑100͒, ͑110͒, and ͑111͒ faces of n-type InAs crystals are investigated as a function of the sample azimuthal orientation under excitation from femtosecond Ti:sapphire laser pulses. The expressions describing the second-order response ͑optical secondharmonic generation and optical rectification͒ in reflection from zinc-blende crystals, such as InAs, are calculated taking into account the bulk electric-dipole contribution and the first-order surface electric-field-induced contribution. It is shown that the two contributions can be separated based on rotation symmetry considerations. Moreover, a direct comparison of the second-harmonic generation and terahertz radiation emission indicates that the observed dominant surface electric-field-induced optical rectification component may be attributed to the large free-carrier contribution to the third-order susceptibility in InAs.

Soft Matter, 2015

In this paper we report first experimental study on the orientation, interaction and directed-ass... more In this paper we report first experimental study on the orientation, interaction and directed-assembly of single crystal micro-sheets in nematic liquid crystals.

Macromolecular rapid communications, Jan 16, 2015

This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers wit... more 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.

Colloidal self-assembly has been one of the major driving themes in material science to obtain fu... more Colloidal self-assembly has been one of the major driving themes in material science to obtain functional and advanced optical materials with complex architecture. Most of the nematic colloids reported so far are based on the optically isotropic spherical microparticles. We study organic single crystal micro-sheets and investigate their orientation, interaction and directed assembly in a nematic liquid crystal. The micro-sheets induce planar surface anchoring of the liquid crystal. The elasticity mediated pair interaction of micro-sheets shows quadrupolar characteristics. The average orientation angle of the micro-sheets in a planar cell and the angle between two micro-sheets in a homeotropic cell are supported by the Landau-de Gennes Q-tensor modeling. The self-assembly of the micro-sheets is assisted by a laser tweezer to form larger two-dimensional structures which have the potential for application of colloids in photonics.

Self-assembled hexgonal organic submicrotubes, upon electronic excitation with an UV laser, displ... more Self-assembled hexgonal organic submicrotubes, upon electronic excitation with an UV laser, display an active type polarized whispering gallery mode (WGM) resonance in the visible (Vis) range (400-600 nm). Due to photonic cavity effect the tubes show fluorescence (FL) signal intensity 5x greater than the corresponding powder state. Further the same tubes which are passive to visible laser, produce yellow-orange emitting carbonaceous lumps when burnt with intense laser beam (42 mW) forming a chemically binary heterogeneous structure. The hetero-structure upon excitation with visible laser at the passive tubular part showed emission in the Vis-Near infrared (NIR) range (500-800 nm) with WGMs thus producing a passive/active type hetero-structure photonic resonator.

Macromolecular Rapid Communications

This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers wit... more 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 (4,82) nanolattices (consist of diamagnetic octagons and SCO squares). The thickness and top area of each SCO square are ≈75 nm and ≈2 × 2 μm2, respectively.

This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers wit... more 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 BF 4 and ClO 4 counter anions is T1/2 = 313 K
and T1/2 = 326 K, respectively. By following the top-down approach, one of the polymers (with
ClO 4 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

Advanced Optical Materials, Nov 28, 2022

Journal of Chemical Sciences, 2018

Crystal Growth & Design, 2018

ACS Applied Energy Materials, 2018

Journal of Materials Chemistry C, 2017

Physical chemistry chemical physics : PCCP, Jan 21, 2016

Physical Review B, 2005

Soft Matter, 2015

Macromolecular rapid communications, Jan 16, 2015

Macromolecular Rapid Communications

This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers wit... more 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 (4,82) nanolattices (consist of diamagnetic octagons and SCO squares). The thickness and top area of each SCO square are ≈75 nm and ≈2 × 2 μm2, respectively.

This paper presents the synthesis of two highly soluble Fe(II) metallosupramolecular polymers wit... more 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 BF 4 and ClO 4 counter anions is T1/2 = 313 K
and T1/2 = 326 K, respectively. By following the top-down approach, one of the polymers (with
ClO 4 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

The spin cross over (SCO) is a reversible magnetic switching between low-spin (LS) and high-spin ... more The spin cross over (SCO) is a reversible magnetic switching between low-spin (LS) and high-spin (LS) states due to the modulation of ligand field strengths depending on the temperature, light and pressure. The molecular bistability of SCO molecules is associated with a lack of fatigue; the bistable magnetic compounds can be used for applications such as sensors and digital memory if we arrange them to form pattern or arrays.
In this poster we would like to show the fabrication of a novel square pillar arrays from spin crossover co-ordination polymer {[FeII(L2)]n(ClO4)2n} (T1/2= 320 K). The square pillar arrays was successfully achieved by Top-Down Approach (2-D Lithography) and LCW technique. We will also discuss the laser based reading and writing technique from 2-D arrays. The synthesis of the back-to back ligands having different types of phenyl spacer (n = 1, 2, 3) starting from a low cost citrazinic acid will also be discussed.