02168nas a2200157 4500008004100000245009300041210006900134260000800203300001600211490000600227520157400233100002501807700002301832700003001855856012501885 2013 eng d00aCleavable and removable polymer thermosets for organic field effect transistor packaging0 aCleavable and removable polymer thermosets for organic field eff cSEP a22591-225960 v33 aRecent years have witnessed tremendous progress in the design and synthesis of electroactive materials for the fabrication of organic electronic devices. However, very little research effort has been devoted to developing organic packaging materials, which are crucial for the efficient functioning of the devices. Polymer thermosets (PTs) are extensively used for the packaging of microelectronic and optoelectronic devices. Although PTs are effective in providing mechanical stability and environmental protection to devices, the removal of PTs without destroying the underlying surface is cumbersome. Facile removal of PTs is essential to reuse the expensive substrates. Herein, we report the preparation of a thermoset using an aliphatic disulfide containing cross-linker, cystamine. By varying the cross-linker concentration, the mechanical property of the thermoset was varied from ductile to brittle. The ductile thermoset was coated on metal, semiconductor and flexible substrates. The thermosets were then cleaved using a biomolecule in neutral pH. We have demonstrated that the cleavage and removal of thermosets don't affect the surface properties of the underlying substrates. Furthermore, the thermosets were coated on top of organic field effect transistors to provide environmental protection. The thermoset coated devices showed a charge carrier mobility of 5.3 x 10(-3) cm(2) V-1 s(-1). Then, the thermoset was cleaved and removed, and the substrate was reused for the fabrication of organic field effect transistors with unchanged device efficiencies.1 aArulkashmir, Arulraj1 aBhosale, Manik, E.1 aKrishnamoorthy, Kothandam uhttp://library.ncl.res.in/content/cleavable-and-removable-polymer-thermosets-organic-field-effect-transistor-packaging-001034nas a2200193 4500008004100000022001400041245013700055210006900192260011000261300001200371490000700383520021200390100002500602700002200627700001900649700001500668700003000683856012700713 2014 eng d a1359-734500aChemically doped perylene diimide lamellae based field effect transistor with low operating voltage and high charge carrier mobility0 aChemically doped perylene diimide lamellae based field effect tr aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a326-3280 v503 a

Chemical doping of an electron transporter results in the formation of a radical anion containing semiconductor which showed high electron mobility (13 cm(2) V-1 s(-1)) at low operating voltage (1 V).

1 aArulkashmir, Arulraj1 aJain, Bhanprakash1 aJohn, Jino, C.1 aRoy, Kanak1 aKrishnamoorthy, Kothandam uhttp://library.ncl.res.in/content/chemically-doped-perylene-diimide-lamellae-based-field-effect-transistor-low-operating-001695nas a2200157 4500008004100000022001400041245009300055210006900148260007100217300001400288490000700302520105100309100002301360700003001383856012401413 2015 eng d a0897-475600aChemically reduced organic small-molecule-based lithium battery with improved efficiency0 aChemically reduced organic smallmoleculebased lithium battery wi a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR a2121-21260 v273 a

Organic lithium batteries are attractive because of the possibility of fabricating lightweight and flexible devices. However, the organic lithium batteries have a few drawbacks. The specific capacity is usually lower than the theoretical capacity, which further decreases upon cycling. Often, the specific capacity is very low compared to theoretical capacity while discharging the battery at moderate and high C rates. To circumvent this issue, we chemically reduced carboxylic acid functionality substituted perylene diimide (benzoic-PDI) with hydrazine. Indeed, we found that the rate of redox reaction as well as the conductivity of the benzoic-PDI increased upon chemical reduction. The battery comprising reduced benzoic-PDI exhibits 100% Coulombic efficiency and specific capacity while discharging at 20C. The battery also exhibits very high specific energy (213 Wh/kg) and specific power (8548 W/kg). The control experiments confirm our hypothesis of using chemical reduction to improve the performance of organic lithium battery.

1 aBhosale, Manik, E.1 aKrishnamoorthy, Kothandam uhttp://library.ncl.res.in/content/chemically-reduced-organic-small-molecule-based-lithium-battery-improved-efficiency-001698nas a2200253 4500008004100000245009000041210006900131260000800200300001000208490000800218520083300226100002801059700003001087700002501117700002001142700002001162700003001182700001601212700003701228700001801265700002401283700002101307856011601328 2016 eng d00a"Click" polymerization: a convenient strategy to prepare designer fullerene materials0 aClick polymerization a convenient strategy to prepare designer f cOCT a34-410 v1083 a"Click" polymeric assemblies of fullerenes, thiophenes and aryl compounds were prepared for the first time to study their spectroscopic/chemical/electronic characteristics and possible applications in photovoltaic cells. The GPC and NMR spectroscopic data confirmed a moderate to high degree of polymerization while microscopic pictures showed well-defined arrangements of fullerenes. The FTIR studies indicated that the product is free from starting azide materials, whereas thermogravimetric analysis data suggested a good stability. Band gap of the material was determined using UV-Vis spectroscopy, cyclic voltammetric techniques and compared with computational investigation. The fullerene copolymer was fabricated as acceptor material in a bulk heterojunction photovoltaic cell. (C) 2016 Elsevier Ltd. All rights reserved.1 aKrishnamurthy, Munusamy1 aKrishnamoorthy, Kothandam1 aArulkashmir, Arulraj1 aRaghavendra, V.1 aMurali, Adhigan1 aJaisankar, Sellamuthu, N.1 aMurugan, P.1 aGurusamy-Thangavelu, Senthil, A.1 aNasar, Sultan1 aMandal, Asit, Baran1 aSamanta, Debasis uhttp://library.ncl.res.in/content/click-polymerization-convenient-strategy-prepare-designer-fullerene-materials00940nas a2200181 4500008004100000022001400041245009800055210006900153260011000222300001200332490000700344520017600351100002300527700002700550700002400577700003000601856012700631 2016 eng d a1359-734500aConjugated porous polymers as precursors for electrocatalysts and storage electrode materials0 aConjugated porous polymers as precursors for electrocatalysts an aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcOCT a316-3180 v523 a

Conjugated porous polymers were used as precursors to prepare nitrogen and sulphur doped carbon atoms, which were then used for oxygen reduction and energy storage.

1 aBhosale, Manik, E.1 aIllathvalappil, Rajith1 aKurungot, Sreekumar1 aKrishnamoorthy, Kothandam uhttp://library.ncl.res.in/content/conjugated-porous-polymers-precursors-electrocatalysts-and-storage-electrode-materials-001701nas a2200157 4500008004100000245012500041210006900166260000800235300001600243490000800259520107100267100001801338700002801356700003001384856012901414 2016 eng d00aCopolymers comprising monomers with various dipole and quadrupole as active material in organic field effect transistors0 aCopolymers comprising monomers with various dipole and quadrupol cNOV a26199-262050 v1203 a

Copolymers of 4,4-difluoro-4-borata-3a-azonia-4a-aza-s-indacene (BODIPY) and diketopyrrolopyrrole (DPP) were synthesized. The BODIPY has a permanent dipole and the DPP has a quadrupole. The dipole and the quadrupole in the monomers are expected to bring the polymers closer and to improve the charge-transport properties. By judicious choice of these monomers, the electron wave function is evenly distributed through the molecules. However, we notice that the torsional angle at the connecting point of BODIPY and DPP is a function of the methyl moieties at the beta,beta' position of the BODIPY. We found that the polymer comprising DPP and BODIPY without methyl moiety at beta,beta' position showed a torsional angle of 27, the lowest among the three polymers studied in this work. The absorption spectrum of the polymer showed transitions because of vibronic coupling indicating linearity along the polymer backbone. The band gap of the polymer was found to be 1.2 eV. The thermally stable polymer showed an ambipolar charge transport of 0.01 cm(2)/(V s).

1 aSingh, Saumya1 aChithiravel, Sundaresan1 aKrishnamoorthy, Kothandam uhttp://library.ncl.res.in/content/copolymers-comprising-monomers-various-dipole-and-quadrupole-active-material-organic-field01599nas a2200157 4500008004100000022001400041245006400055210006400119260000800183300001400191490000700205520108700212100002201299700003001321856009001351 2019 eng d a2040-336400aConversion of curved assemblies into two dimensional sheets0 aConversion of curved assemblies into two dimensional sheets cMAR a5732-57360 v113 a

The design and preparation of organic two dimensional (O2D) sheets and their conversion to curved nanostructures is in its infancy. To convert a flat structure into a curved structure, the molecule must have multiple interaction possibilities and an in-built twist. The conjugated small molecule iso-Indigo (i-Indigo) comprises two phenyl rings that are twisted (the dihedral angle is 15 degrees) at the junction. The i-Indigo has been connected with moieties that impart hydrogen bonding and van der Waals interactions. Due to the presence of the cloud in i-Indigo, - interactions are also present in the molecule. While all three interactions are in operation, rings and toroids are formed. Upon addition of hydrogen bonding competing solvents, the rings and toroids unravel to form O2D sheets. Control molecules that don't have hydrogen bonding moieties and - interactions form random assemblies. Please note that the rings, toroids and O2D sheets are formed in a single solvent by simple dissolution, unlike previous approaches that involve multiple steps and solvents.

1 aDeshmukh, Gunvant1 aKrishnamoorthy, Kothandam uhttp://library.ncl.res.in/content/conversion-curved-assemblies-two-dimensional-sheets01959nas a2200193 4500008004100000245010500041210006900146260000800215490000600223520124600229653002101475653001301496653002701509653002701536653002701563100002101590700003001611856012401641 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 uhttp://library.ncl.res.in/content/concurrent-polyvalent-interaction-and-electrocatalysis-improve-lithium-sulfur-battery02391nas a2200205 4500008004100000245009400041210006900135260000800204490000600212520167000218653002101888653001301909653002901922653001801951653001701969100002101986700002102007700003002028856012702058 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 uhttp://library.ncl.res.in/content/can-metal-cations-electrocatalyze-sulfur-redox-reaction-and-suppress-polysulfide-shuttle