02097nas a2200181 4500008004100000245010100041210006900142260000800211300001400219490000600233520141200239100002501651700002601676700002901702700002201731700003001753856013201783 2012 eng d00aSupramolecular interaction facilitated small molecule films for organic field effect transistors0 aSupramolecular interaction facilitated small molecule films for  cAPR a1641-16460 v33 aMetalloporphyrins and metal free porphyrins have been explored as active materials in field effect transistors. Amorphous forms of these porphyrins are preferred over their crystalline analogue due to the ease of solution processability. To achieve solution processability, a metalloporphyrin was anchored on a vinyl polymer by taking advantage of the supramolecular interaction between the metal and the pyridine moiety of the polymer. Non covalent bonding was preferred because it provides an opportunity to better manipulate the polymer's properties compared to its covalent bonding analogue. The binding between the porphyrin and the polymer was optimised in solution and the supramolecular complex was spun on various substrates to form thin films. The porphyrin was found to be uniformly distributed throughout the polymer films contrary to the existing approaches, wherein small molecule phase segregates in the polymer film. Field effect transistors were fabricated using the porphyrin-polymer complex and the device parameters were measured at atmospheric condition. The devices annealed at 80 degrees C showed hole carrier mobility of 2.0 x 10(-4) cm(2) V-1 s(-1) with charge trapping at the dielectric semiconductor interface. Furthermore, the high carrier mobility observed at low temperature annealing makes this supramolecular complex an attractive candidate to explore in flexible substrates.1 aArulkashmir, Arulraj1 aMahale, Rajashree, Y.1 aDharmapurikar, Satej, S.1 aJangid, Manoj, K.1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/supramolecular-interaction-facilitated-small-molecule-films-organic-field-effect-transistors01678nas a2200193 4500008004100000022001400041245009400055210006900149260000800218300001600226490000700242520098400249100001801233700002801251700003001279700002301309700003001332856012201362 2015 eng d a1359-734500aSeeded on-surface supramolecular growth for large area conductive donor-acceptor assembly0 aSeeded onsurface supramolecular growth for large area conductive cMAY a10439-104420 v513 a

Charge transport features of organic semiconductor assemblies are of paramount importance. However, large-area extended supramolecular structures of donor-acceptor combinations with controlled self-assembly pathways are hardly accessible. In this context, as a representative example, seeded on-surface supramolecular growth of tetrathiafulvalene and tetracyano-p-quinodimethane (TTF-TCNQ) using active termini of solution-formed sheaves has been introduced to form an extended assembly. We demonstrate for the first time, the creation of a large-area donor-acceptor assembly on the surface, which is practically very tedious, using a seeded, evaporation-assisted growth process. The excellent molecular ordering in this assembly is substantiated by its good electrical conductivity (similar to 10(-2) S cm(-1)). The on-surface assembly via both internally formed and externally added sheaf-like seeds open new pathways in supramolecular chemistry and device applications.

1 aGoudappagouda1 aChithiravel, Sundaresan1 aKrishnamoorthy, Kothandam1 aGosavi, Suresh, W.1 aBabu, Sukumaran, Santhosh uhttps://library.ncl.res.in/content/seeded-surface-supramolecular-growth-large-area-conductive-donor-acceptor-assembly02250nas a2200193 4500008004100000022001400041245013100055210006900186260007100255300001600326490000800342520147800350100001901828700001801847700001601865700003001881700002101911856012401932 2015 eng d a1932-744700aSynthesis, optoelectronic, and transistor properties of BODIPY- and cyclopenta[c]thiophene-containing pi-conjugated copolymers0 aSynthesis optoelectronic and transistor properties of BODIPY and a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL a15859-158670 v1193 a

Three new low-band-gap copolymers were synthesized by fusing dipyrromethene difluoroborane (BODIPY) as the acceptor (A) and thiophene-capped 5,5-bis(hexyloxymethyl)-5,6-dihydro-4H-cyclopenta[c]-thiophene (CPT) as the donor (D). The BODIPY unit was copolymerized through the `alpha' positions (1 and 7 positions) in P1 and through the `beta' positions (2 and 6 positions) in P2 and P3. The additional acetylene unit between D and A in P3 enhanced the conjugation by minimizing the possible steric hindrance compared to that in P2, whereas P1 exhibited a more red-shifted absorption than P2 and P3 because of the more effective conjugaion through the `alpha' positions of BODIPY. Importantly, the optical band gaps (E-g(opt)) obtained from the onset of the absorption spectra are 1.28, 1.71, and 1.57 eV for P1, P2, and P3, respectively. P1 has the lowest band gap for any CPT-containing polymer. In the best transistor devices, a mobility improvement by 4 orders of magnitude from 3.22 x 10(-6) cm(2) V-1 s(-1) for P2 to 0.01 cm(2) V-1 s(-1) for P1 was achieved. DFT calculations alongside measured charge-transport properties indicated that appreciable alterations in the optoelectronic properties of the polymers were achieved through minor changes in their structural features. The polymers were further characterized by thin-film X-ray diffraction, atomic force microscopy, and spectroelectrochemistry to investigate their material and electrochemical properties.

1 aDebnath, Sashi1 aSingh, Saumya1 aBedi, Anjan1 aKrishnamoorthy, Kothandam1 aZade, Sanjio, S. uhttps://library.ncl.res.in/content/synthesis-optoelectronic-and-transistor-properties-bodipy-and-cyclopentacthiophene-102037nas a2200193 4500008004100000245013800041210006900179260000800248300001600256490000600272520131300278100001901591700002801610700001801638700001601656700003001672700002101702856012001723 2016 eng d00aSelenium-containing fused bicyclic heterocycle diselenolodiselenole: field effect transistorstudy and structure property relationship0 aSeleniumcontaining fused bicyclic heterocycle diselenolodiseleno cJUL a18222-182300 v83 aThe first application of the diselenolodiselenole (C4Se4) heterocycle as an active organic field effect transistor materials is demonstrated here. C4Se4 derivatives (2a-2d) were obtained by using a newly developed straightforward diselenocyclization protocol, which includes the reaction of diynes with selenium powder at elevated temperature. C4Se4 derivatives exhibit strong donor characteristics and planar structure (except 2d). The atomic force microscopic analysis and thin-film X-ray diffraction pattern of compounds 2a-2d indicated the formation of distinct crystalline films that contain large domains. A scanning electron microscopy study of compound 2b showed development of symmetrical grains with an average diameter of 150 nm. Interestingly, 2b exhibited superior hole mobility, approaching 0.027 cm(2) V-1 s(-1) with a transconductance of 9.2 mu S. This study correlate the effect of p-stacking, Se center dot center dot center dot Se intermolecular interaction, and planarity with the charge transport properties and performance in the field effect transistor devices. We have shown that the planarity in C4Se4 derivatives was achieved by varying the end groups attached to the C4Se4 core. In turn, optoelectronic properties can also be tuned for all these derivatives by end-group variation.1 aDebnath, Sashi1 aChithiravel, Sundaresan1 aSharma, Sagar1 aBedi, Anjan1 aKrishnamoorthy, Kothandam1 aZade, Sanjio, S. uhttps://library.ncl.res.in/content/selenium-containing-fused-bicyclic-heterocycle-diselenolodiselenole-field-effect02081nas a2200241 4500008004100000022001400041245011300055210006900168260006700237300001400304490000700318520123700325653001401562653001101576653000801587653001701595100001901612700001801631700001601649700003001665700002101695856012301716 2016 eng d a0887-624X00aSite-selective synthesis and characterization of BODIPY-acetylene copolymers and their transistor properties0 aSiteselective synthesis and characterization of BODIPYacetylene  a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJUL a1978-19860 v543 a

To study the effect of site-selective copolymerization of borondipyrromethene (BODIPY) with acetylene on the structural and optoelectronic properties, three copolymers P1-P3 were synthesized by the Sonogashira cross-coupling of BODIPY units with diacetylene and bromine capping through all the possible linkages: alpha-alpha (P1), alpha-beta (P2), and beta-beta (P3). The optoelectronic properties of the polymers were investigated systematically to understand the effect of site-selective polymerization. The HOMO levels of the polymers were significantly tuned from P1 to P3 with negligible change in the LUMO levels. Broadening of absorption spectra from P3 to P1 was observed because of increase in the extent of conjugation. Additionally, the charge transport properties of these polymers in organic thin-film transistors (OTFTs) revealed that P1 and P3 exhibited only p-type mobility, whereas P2 exhibited electron mobility. Notably, the further investigations of the surface morphology of polymer films by atomic force microscopy (AFM) unveiled that comb like nanostructural arrangements in P3 was beneficial for the charge-carrier mobility over the circular arrangements in P1 and P2. (C) 2016 Wiley Periodicals, Inc.

10aacetylene10aBODIPY10aDFT10alow-band gap1 aDebnath, Sashi1 aSingh, Saumya1 aBedi, Anjan1 aKrishnamoorthy, Kothandam1 aZade, Sanjio, S. uhttps://library.ncl.res.in/content/site-selective-synthesis-and-characterization-bodipy-acetylene-copolymers-and-their01635nas a2200169 4500008004100000245014100041210006900182260000800251300001400259490000700273520096500280100001601245700002201261700002401283700003001307856012801337 2016 eng d00aSynthesis and characterization of simple cost-effective trans-A(2)BC porphyrins with various donor groups for dye-sensitized solar cells0 aSynthesis and characterization of simple costeffective transA2BC cJUL a5704-57130 v403 aWe have designed and synthesized a series of simple cost-effective 'push-pull' Zn(II) porphyrin dyes containing various electron donors such as 2-thienyl, pyrenyl, phenyl, 4'-bromophenyl, 4'-tbutylphenyl and 4'-carboxyphenyl acceptor moieties in three steps. Their optical absorption spectra, electrochemical redox and photovoltaic properties have been investigated in detail. The overall power conversion efficiencies (Z) of DSSCs based on these dyes are in the range of 2.1 to 4.2% and highly depend on their donor moiety. The incorporation of trans-10,20-dimesityl groups is highly beneficial for preventing the p-p aggregation among the porphyrin moieties, thus favorably suppressing the charge recombination and intermolecular interaction. Among all, pyrenyl appended Zn(II) porphyrin has exhibited a higher power conversion efficiency of 4.2% under 1 sun illumination due to the extended p-conjugation and electron donating ability of the pyrenyl moiety.1 aKumar, Ravi1 aSankar, Muniappan1 aSudhakar, Vediappan1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/synthesis-and-characterization-simple-cost-effective-trans-a2bc-porphyrins-various-donor01571nas a2200145 4500008004100000245009500041210006900136260000800205300001600213490000700229520101700236100002301253700003001276856011901306 2017 eng d00aSelf-assembled spheres, flowers, and fibers from the same backbone and similar side chains0 aSelfassembled spheres flowers and fibers from the same backbone  cNOV a13401-134060 v333 aRylene imides (Ms) self-assemble into various nanostructures. Often, the synthesis of unsymmetrical RIs (URIs) is required to achieve nanostructures. However, the synthesis of URIs is nontrivial. Thus, a structurally similar alternative is desirable. iso-Indigo (i-indigo) has a pi core and lactam rings that are structurally similar to the RIs. Unsymmetrical iso-indigo (i-indigo) can be easily synthesized by condensing oxindole and isatin. We have synthesized a series of unsymmetrical i-indigo molecules. In these molecules, the pi-pi interaction, hydrogen bonding, and van der Waals interactions are in operation. Because of these, the molecules self-assemble into spheres, fibers, and dahlia flower morphologies. If the hydrogen bonding interaction is disrupted, then all of them form fibers. Control experiments indicate that the complete absence of hydrogen bonding is deleterious to self-assembly. We also show that the lower analogs of i-indigo are not sufficient to form self-assembled nanostructures.1 aSingh, Anup, Kumar1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/self-assembled-spheres-flowers-and-fibers-same-backbone-and-similar-side-chains01695nas a2200217 4500008004100000022001400041245008100055210006900136260000800205300001400213490000600227520098600233653002201219653001601241653001801257653002301275100002401298700001901322700003001341856010601371 2018 eng d a2365-654900aSilk cocoon as counter - electrode substrate in dye - sensitized solar cells0 aSilk cocoon as counter electrode substrate in dye sensitized sol cJUL a7195-71990 v33 a

Electrodes are vital components of energy conversion devices such as dye sensitized solar cells (DSSCs). The widely used electrodes consist of fluorine doped tin oxide (FTO) and platinum. We were interested in identifying a substrate that is available from natural resources and exhibit performance comparable to that of Pt coated FTO (Pt-FTO). Silk fibers are naturally available and they are mechanically stable. The woven silk fibers are known as silk cocoons (SCs) that structurally resemble widely used carbon paper electrodes. To impart conductivity to the insulating SCs, metal film was coated by an electroless metal plating procedure using polyphenols from green tea. The metal coated SCs were conformaly coated with a conjugated polymer and these electrodes were used as flexible electrodes in DSSCs. The flexible electrode based DSSCs exhibited a power conversion efficiency of 7.2% which is comparable to that of the DSSCs with rigid Pt-FTO based devices (7.4%).

10acounter electrode10aPEDOT-G-SCs10aRecombination10aSilk cocoons (SCs)1 aSudhakar, Vediappan1 aDas, Chayanika1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/silk-cocoon-counter-electrode-substrate-dye-sensitized-solar-cells03453nas a2200253 4500008004100000022001400041245009600055210006900151260000800220300001600228490000800244520261200252653001102864653001002875653001302885653001702898100002802915700002702943700002202970700002602992700003003018700002703048856012403075 2023 eng d a1932-744700aSteric and electronic effect in unsymmetrical squaraine dyes for dye-sensitized solar cells0 aSteric and electronic effect in unsymmetrical squaraine dyes for cNOV a22473-224880 v1273 a

Functionalizing the light harvesting sensitizers with additional electron-donating or -withdrawing groups is a potential approach to modulate the photophysical and electrochemical properties which in-turn optimizes the driving force associated with the charge injection and dye-regeneration processes at the dye-TiO2/electrolyte interface and the photovoltaic device performance in dye-sensitized solar cells (DSSCs). Furthermore, modulated electronic levels of the dyes provide an opportunity to reduce the overpotential associated with the dye-regeneration process and make the dye-TiO2 interface compatible with various electrolytes. Furthermore, an in-built steric feature by means of introducing linear/branched alkyl groups in the sensitizer is important in controlling the aggregation of dyes on the TiO2 surface. Hence, to integrate both steric and electronic properties, a series of alkyl group-wrapped unsymmetrical squaraine dyes (SQ-X) with electron-donating and -withdrawing groups have been designed, synthesized, and utilized for DSSC device fabrication. These dyes are functionalized with alkyl groups at both sp(3)-C and N-atoms of the indoline donor moiety at the nonanchoring side to have a similar steric feature. Photophysical and electrochemical studies revealed that the HOMO and LUMO energy levels of the SQ-X series of dyes have been modulated systematically with sufficient driving forces for both charge injection and dye-regeneration processes with iodolyte (I-/I-3(-)) electrolyte. In the presence of electron-donating groups in SQ-X (where X = -NPh2 and -OMe), the HOMO energy levels are less positive than SQ-H, whereas the presence of electron-withdrawing groups such as -CO2Me, -CN, and -NO2 pushed the HOMO energy levels toward more positive potentials. Enhanced photovoltaic performances have been obtained for the dyes containing electron-donating groups, where the dye with the -NPh2 group showed a maximum of eta 7.03% (V-OC 708 mV, J(SC) 13.16 mA cm(-2), and ff 78%). The dye with the strong electron-withdrawing group -NO2 showed an efficiency of 1.49% (V-OC = 634 mV, J(SC) = 3.13 mA cm(-2), and ff 75%). As the dyes with the electron-withdrawing group possess deep positive HOMO energy levels, the DSSC device characterization has been investigated with the Cu+/2+ redox shuttle. The reduced device performance of electron-withdrawing-group-containing dyes is due to the unfavored charge distribution in the LUMO compared to the presence of electron-donating-group-containing dyes, and it was supported by the difference in the charge injection efficiency.

10acobalt10aDonor10aDynamics10aOrganic dyes1 aNawghare, Indrajeet, S.1 aSingh, Ambarish, Kumar1 aMaibam, Ashakiran1 aKrishnamurty, Sailaja1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/steric-and-electronic-effect-unsymmetrical-squaraine-dyes-dye-sensitized-solar-cells02492nas a2200193 4500008004100000022001400041245016000055210006900215260000800284300001400292490000700306520172000313100002402033700003402057700002502091700002002116700003002136856013202166 2024 eng d a0024-929700aShuttle balance between lithiophilic functionalities substituted on conjugated polymers to improve lithium-ion diffusion and cycling stability of batteries0 aShuttle balance between lithiophilic functionalities substituted cAUG a7830-78400 v573 a

Herein, we report the design and synthesis of i-Indigo and trans-1,2-di(2-thienyl)ethylene (TVT) comprising copolymers with various side chains that are used as anode-cum-binder in Li-ion batteries. The TVT disrupts the crystallinity, and the i-Indigo renders the handle for unsymmetrical substitution. Polymer P1 comprises alkyl chains on i-Indigo, whereas P2 comprises an alkyl chain and a chain with a urethane moiety as another side chain. Polymer P3 comprises i-Indigo with a urethane moiety and triethylene glycol as side chains. The i-Indigo in P4 is substituted with triethylene glycol and alkyl chains as side chains. These polymers were found to be amorphous with pi-pi stacking due to the extremely small torsional angle imparted by TVT moieties. All of these polymers showed comparable specific capacity while used as an anode in Li-ion batteries due to the presence of a common conjugated backbone. However, the battery metrics varied significantly while the current density of the batteries varied between 0.1 and 2.0 A g(-1). P1 and P2 showed a very close recovery of specific capacity at 0.1 A g(-1) before and after various current densities. However, polymers P3 and P4 did not recover from the specific capacity fading due to the presence of triethylene glycol side chain that degraded. Polymer P2 with an alkyl side chain and a chain with a urethane moiety showed stable performance over 2000 charge-discharge cycles. Contrary to this, the stability of polymers with triethylene glycol side chains decreased over 2000 charge-discharge cycles. Polymer P2 with a urethane side chain also showed improved Li-ion diffusion because the urethane moiety facilitated better Li-ion transport.

1 aKargude, Radhakisan1 aJavaregowda, Bharathkumar, H.1 aPalani, Sathishkumar1 aSingh, Anup, K.1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/shuttle-balance-between-lithiophilic-functionalities-substituted-conjugated-polymers-improve00945nas a2200253 4500008004100000022001400041245013300055210006900188260000900257300001600266490000700282653001700289653003200306653003400338100003400372700002400406700002100430700002300451700002600474700002100500700002300521700003000544856011700574 2024 eng d a1944-824400aSynergistic effect of lactam and pyridine nitrogen on polysulfide chemisorption and electrocatalysis in lithium sulfur batteries0 aSynergistic effect of lactam and pyridine nitrogen on polysulfid cAUG  a42059-420680 v1610aLi-S battery10aphenyl-diketopyrrolopyrrole10apyridine-diketopyrrolopyrrole1 aJavaregowda, Bharathkumar, H.1 aKargude, Radhakisan1 aBirajdar, Sarika1 aShivankar, Bhavana1 aKrishnamurty, Sailaja1 aJones, Lathe, A.1 aCaruso, Rachel, A.1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/synergistic-effect-lactam-and-pyridine-nitrogen-polysulfide-chemisorption-and