01967nas a2200205 4500008004100000245015000041210006900191260000800260300001400268490000600282520117400288100002001462700002001482700002101502700002801523700003001551700003001581700002501611856012501636 2016 eng d00aAlkyl-chain-separated triphenybenzene - carbazole conjugates and their derived polymers: candidates for sensory, electrical and optical materials0 aAlkylchainseparated triphenybenzene carbazole conjugates and the cDEC a6649-66570 v13 aFour new triphenylbenzene based carbazoles (THPBCz4, THPBCz6, THPBCz8 and THPBCz10) and polycarbazoles (polyTHPBCz4, polyTHPBCz6, polyTHPBCz8 and polyTHPBCz10), have been synthesized. Photoluminescence spectra of the monomers in dichloromethane exhibit two intense bands at 353 and 369 nm. Two additional bands (410 and 435 nm) are also observed due to intermolecular interactions. These bands are more intense in the case of thin films, indicating stronger pp stacking interactions in the solid state. Due to the extended p-conjugation, the polycarbazoles display two main emission bands (495 and 520 nm) which are red shifted as compared to the monocarbazoles. Due to the presence of emissive platforms such as triarylbenzene and carbazole, both monomers and polymers, function as efficient sensors for the detection of polynitroaromatic analytes (PA, DNT, rho-DNB and m-DNB). The electrochemically polymerized carbazole derivatives showed maximum capacitance of 41 F/g for polyTHPBCz6. The SCLC measurement reveals a maximum mobility of 6 x 10(-6) cm(2)/Vs for polyTHPBCz4 that showed better packing due to flexible alkyl chains that connect the conjugated moieties.1 aKaleeswaran, D.1 aVishnoi, Pratap1 aKumar, Subramani1 aChithiravel, Sundaresan1 aWalawalkar, Mrinalini, G.1 aKrishnamoorthy, Kothandam1 aMurugavel, Ramaswamy uhttps://library.ncl.res.in/content/alkyl-chain-separated-triphenybenzene-carbazole-conjugates-and-their-derived-polymers01960nas a2200193 4500008004100000245010500041210006900146260000800215490000600223520124600229653002101475653001301496653002701509653002701536653002701563100002101590700003001611856012501641 2022 eng d00aConcurrent polyvalent interaction and electrocatalysis to improve lithium-sulfur battery performance0 aConcurrent polyvalent interaction and electrocatalysis to improv cFEB0 v53 a

Batteries with improved efficiency are desired. Li-S batteries are attractive due to their high specific capacity and energy density. However, sluggish sulfur redox reaction and polysulfide dissolution are significant challenges in Li-S batteries. In this work, we report graphene with doped layer to electrocatalyze the sluggish sulfur redox reaction. The doped layer comprises heteroatoms such as either N or N and S. The doped layer also comprises cations of Ni. We have chosen a ``doped layer on graphene'' over ``doped graphene'' to avoid defects in the basal plane of graphene. We found the doped layer comprising graphene (DLC-G) to electrocatalyze the polysulfide redox reaction. However, the interaction between the doped layer and polysulfide is still weak, hence the dissolution is not suppressed. To circumvent the polysulfide dissolution, graphene with cationic layer was prepared. We found that cations in the layer electrostatically attract the polysulfides due to the polyvalent interaction. Thus, the dissolution is suppressed. While using this material in the Li-S batteries, the specific capacity, energy density and power density were found to be 1345 mAh g(-1), 782 Wh kg(-1) and 4437 W kg(-1), respectively.

10aelectrocatalysis10agraphene10alithium-sulfur battery10amechanical exfoliation10apolyvalent interaction1 aKumar, Subramani1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/concurrent-polyvalent-interaction-and-electrocatalysis-improve-lithium-sulfur-battery02392nas a2200205 4500008004100000245009400041210006900135260000800204490000600212520167000218653002101888653001301909653002901922653001801951653001701969100002101986700002102007700003002028856012802058 2023 eng d00aCan metal cations electrocatalyze sulfur redox reaction and suppress polysulfide shuttle?0 aCan metal cations electrocatalyze sulfur redox reaction and supp cSEP0 v63 a

In lithium-sulfur (Li-S) batteries, sulfur undergoes various changes. It switches between cyclic structure and linear structure. The charge on the sulfur varies between a neutral state and a negative charge-bearing state. Due to these changes, the sulfur/polysulfide dissolves in the battery electrolyte. Furthermore, the kinetics of the sulfur redox reaction is sluggish. Therefore, a material that can suppress sulfur/polysulfide dissolution and electrocatalyze sulfur redox reaction is needed. We hypothesize that the polysulfide dissolution can be suppressed if the host exhibits polyvalent electrostatic attraction. Polysulfide is a negative charge-bearing molecule; hence the host must comprise multiple positive charges. Nickel cations with other heteroatoms have been explored as a host in Li-S batteries. The heteroatoms impart additional interactions. The easier way to circumvent the effect of heteroatoms is the addition of metal salts. However, metal salts can either exhibit monovalent or divalent attraction with polysulfides. Those interactions are weak and we must have polyvalent interaction. Towards this objective, we have designed and synthesized a material that comprises multiple divalent cations that is also devoid of heteroatoms. The Li-S batteries fabricated using the metal cation immobilized graphene showed a maximum specific capacity of 1022 mAh/g at 0.1 C rate. Among the metal cations, nickel cations showed better performance than cobalt cations. Thus, we demonstrate that metal cations immobilized on Graphene can efficiently electrocatalyze the sluggish sulfur redox reaction and suppress the polysulfide dissolution.

10aelectrocatalysis10agraphene10alithium-sulfur batteries10ametal cations10apolysulfides1 aKumar, Subramani1 aSwain, Gitanjali1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/can-metal-cations-electrocatalyze-sulfur-redox-reaction-and-suppress-polysulfide-shuttle02592nas a2200205 4500008004100000022001400041245011800055210006900173260000900242520181500251653002502066653003602091653001902127653002702146653002002173100002102193700002102214700002402235856012702259 2024 eng d a1022-135200aVariations in packing as a function of side chains in random copolymers and its impact on charge carrier mobility0 aVariations in packing as a function of side chains in random cop cOCT 3 a

Homopolymers and alternating copolymers of conjugated molecules exhibit impressive performance in electronic devices. Despite the well-established procedures, the synthesis of alternating copolymers using three monomers is not as easy as random copolymers. Besides facile synthesis, the random copolymers can match the performance of alternating copolymers in electronic devices. Herein, random copolymers are designed and synthesized comprising thienoisoindigo (TIIG), diketopyrrolopyrrole (DPP), and thiophene. The DPP monomers installed with various side chains including branched alkyl chain, branched alkyl chain with ester functionality, linear oligo ethylene glycol, and siloxane terminated alkyl chain are incorporated into the polymers (P1, P2, P3, and P4, respectively). All the thermally stable, low bandgap random copolymers exhibited strong H-type aggregation in thin film. The relationship between thin film microstructure originating from diverse side chains and the charge transport in organic field effect transistors (OFETs) is investigated. All the random copolymers exhibited predominantly p-type charge transport and a maximum hole mobility of 2 x 10-2 cm2 V-1s-1 is observed for P3. The packing of all the polymers is examined theoretically by density functional theory (DFT) and compared with experimental values obtained from grazing incident X-ray diffraction (GIXRD). Various side chains (hydrophilic and hydrophobic) affect molecular packing of random polymers which ultimately affects its thin film morphology and semiconducting performances. Linear chains provide better interchain packing by pi-pi stacking compared to bulky branched side chains. The incorporation of heteroatoms and polar groups into the side chain further enhances the interchain interactions. image

10adiketopyrrolopyrrole10aorganic field effect transistor10arandom polymer10aside chain engineering10athienoisoindigo1 aSwain, Gitanjali1 aKumar, Subramani1 aSamudre, Nikhil, S. uhttps://library.ncl.res.in/content/variations-packing-function-side-chains-random-copolymers-and-its-impact-charge-carrier