02439nas a2200265 4500008004100000022001400041245012600055210006900181260007100250300001400321490000600335520144400341653001801785653001301803653003601816653002701852653002001879653001901899100002901918700002501947700001901972700002001991700003002011856013202041 2013 eng d a1944-824400aEnhanced hole carrier transport due to increased intermolecular contacts in small molecule based field effect transistors0 aEnhanced hole carrier transport due to increased intermolecular  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcAUG a7086-70930 v53 a

Small molecules and oligomers can be synthesized with very high purity and precise molecular weights, but they often do not form uniform thin films while processed from solution. Decreased intermolecular contacts between the small molecules are another disadvantage. To increase the intermolecular contacts in small molecules, we have chosen i-indigo, as one of the conjugated molecular units. The electron poor i-indigo has been connected with electron rich triphenylamine to synthesize a donor-acceptor-donor type small molecule. The propeller shaped triphenylamine helps to increase the solubility of the small molecule as well as isotropic charge transport. The intermolecular spacing between the molecules has been found to be low and did not vary as a function of thermal annealing. This implies that the intermolecular contacts between the small molecules are enhanced, and they do not vary as a function of thermal annealing. Organic field effect transistors (OFET) fabricated using a small molecule exhibited a hole carrier mobility (mu) of 0.3 cm(2)/(V s) before thermal annealing. A marginal increase in mu was observed upon thermal annealing at 150 degrees C, which has been attributed to changes in thin film morphology. The morphology of the thin films plays an important role in charge transport in addition to the intermolecular spacing that can be modulated with a judicious choice of the conjugated molecular unit.

10ahole mobility10ai-indigo10aorganic field effect transistor10aquadrupole interaction10asmall molecules10atriphenylamine1 aDharmapurikar, Satej, S.1 aArulkashmir, Arulraj1 aDas, Chayanika1 aMuddellu, Pooja1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/enhanced-hole-carrier-transport-due-increased-intermolecular-contacts-small-molecule-based-001750nas a2200205 4500008004100000245009700041210006900138260000800207300001600215490000600231520099100237100002601228700003001254700002801284700003001312700002401342700002801366700002101394856012901415 2018 eng d00aExperimental and theoretical investigations of different diketopyrrolopyrrole-based polymers0 aExperimental and theoretical investigations of different diketop cSEP a11710-117170 v33 aDiketopyrrolopyrrole (DPP)-based polymers are often considered las the most promising donor moiety in traditional bulk heterojunction solar cell devices. In this paper, we report the synthesis, characterization of various DPP-based copolymers with different molecular weights, l and polydisper sity where other aromatic repeating units (phenyl or thiophene based) are connected by alternate double bonds or triple bonds. Some of the copolymers were used for device fabrication and the crucial parameters such as fill factor (FF) and open circuit voltage (V-oc) were calculated. The density functional theory was used to optimize the geometries and deduce highest occupied molecular orbital lowest unoccupied molecular orbital gaps of all the polymers and'theoretically predict their optical and electronic properties. Optical properties of all the polymers, electrochemical properties and band gaps were also obtained experimentally and compared with the theoretically predicted values.1 aMurugan, Pachaiyappan1 aRaghavendra, Venkatraman.1 aChithiravel, Sundaresan1 aKrishnamoorthy, Kothandam1 aMandal, Asit, Baran1 aSubramanian, Venkatesan1 aSamanta, Debasis uhttps://library.ncl.res.in/content/experimental-and-theoretical-investigations-different-diketopyrrolopyrrole-based-polymers01694nas a2200157 4500008004100000022001400041245007200055210006900127260000900196300001600205490000600221520116200227100002401389700003001413856009301443 2019 eng d a2050-752600aEnhancing the device efficiency by filling the traps in photoanodes0 aEnhancing the device efficiency by filling the traps in photoano cDEC  a14632-146380 v73 a

Traps are ubiquitous in semiconductors and act as recombination sites. These recombination sites have a deleterious effect on the device efficiency. Thus, trap filling is used to increase the efficiency of devices. The traps are filled by dopants that either inject or extract electrons to/from the semiconductor. The trap-filled devices exhibit superior performance as compared to their unfilled counterparts. However, to date, this approach has not been explored in dye-sensitized solar cells despite the well-established presence of traps in them. The traps in the TiO2 photoanode are due to the presence of oxygen vacancies. Therefore, herein, we treated the photo anodes with hydrazine and filled the traps that increased all device metrics. Moreover, further sintering of the trap-filled photoanodes in the presence of hydrazine led to the formation of a nitrogen-doped photoanode. The device comprising a nitrogen-doped photoanode exhibited the efficiency increase of 23%. The detailed analysis of the device performance led to the conclusion that trap filling suppressed back electron transfer and increased the photo conversion efficiency.

1 aSudhakar, Vediappan1 aKrishnamoorthy, Kothandam uhttps://library.ncl.res.in/content/enhancing-device-efficiency-filling-traps-photoanodes02541nas a2200253 4500008004100000022001400041245016400055210006900219260000800288300001400296490000800310520162600318653003101944653002001975653001901995653000802014100002802022700002002050700002002070700002402090700003002114700002102144856012202165 2019 eng d a0169-433200aEvolution of ZnO nanostructures as hexagonal disk: Implementation as photoanode material and efficiency enhancement in Al: ZnO based dye sensitized solar cells0 aEvolution of ZnO nanostructures as hexagonal disk Implementation cMAR a1130-11380 v4703 a

Hexagon shaped pristine and Al doped ZnO nanodisks (NDs) with exposed +/- [0001] polar facets were successfully synthesized using modified sol-gel method without the involvement of any structural directing or capping agents. It was investigated that OH- ions in mixed solvent system is responsible for pore formation and inhibit the growth of ZnO along the direction of c-axis leading to a high percentage exposure of active +/- [0001] polar facets and encourage the formation of ZnO NDs. Crystallographic analysis revealed that crystallite size and lattice constants are decreased, with the addition of Al3+ ions. The results obtained from Raman, and XPS analysis further corroborated with the XRD results, revealed the successful incorporation of Al3+ ions into ZnO lattice. Optical study revealed the band gap tunability with the incorporation of Al ion as dopant. Enhanced power conversion efficiency (PCE) of 1.96% (J(sc) similar to 7.69 +/- 0.23 mA/cm(2)) was observed for Al: ZnO hexagonal NDs based DSSC. The increased PCE in Al: ZnO based DSSC can be attributed to the higher inner surface area for dye anchoring by the interconnected network of the disk-like structure. The obtained results were satisfactory and most importantly the synthesis procedure proposed in present work is excellent for the synthesis of perfectly hexagonal shaped disks under precised synthesis parameters. The device interface study was further conducted using electrochemical impedance spectroscopy which revealed better charge transport process and charge storage ability with the incorporation of Al3+ ions into ZnO lattice.

10adye sensitized solar cells10aHexagonal disks10aSol-gel method10aZnO1 aParra, Mohammad, Ramzan1 aPandey, Padmini1 aSiddiqui, Hafsa1 aSudhakar, Vediappan1 aKrishnamoorthy, Kothandam1 aHaque, Fozia, Z. uhttps://library.ncl.res.in/content/evolution-zno-nanostructures-hexagonal-disk-implementation-photoanode-material-and02118nas a2200301 4500008004100000022001400041245011200055210006900167260000900236300001400245490000600259520110900265653002601374653002901400653001801429653001501447653001901462100001801481700002801499700002201527700002101549700002101570700002101591700002201612700003001634700002301664856012901687 2020 eng d a2196-021600aEffect of aromatic rings and substituent on the performance of lithium batteries with rylene imide cathodes0 aEffect of aromatic rings and substituent on the performance of l cMAR  a1160-11650 v73 a

Rylene imides (RIs) are attractive organic battery materials because of the inherent modularity of the molecules. While strong aggregation of RIs is disadvantageous for fast lithium-ion transport in the organic active material, decreasing the solubility of the RIs in battery electrolytes is essential to avoid performance fading. Therefore, the design and synthesis of RIs for lithium batteries is a non-trivial task that must, among other considerations, balance lithium-ion transport in the solid material vs. low solubility by controlling aggregation and packing. We have chosen triphenylamine (TPA) as a substituent which disrupts the aggregation but maintains a low solubility due to increased aromaticity of TPA. We have synthesized three RIs with one, two, and four aromatic units in the core. All of them showed stable specific capacity over 300 charge-discharge cycles. The batteries also showed specific capacities close to their theoretical capacities with 97-99 % coulombic efficiency. The maximum specific energy and specific power were 197 mWh g(-1) and 37 mW g(-1), respectively.

10alithium-ion batteries10aorganic cathode material10arylene imides10asolubility10atriphenylamine1 aAher, Jagdish1 aGraefenstein, Alexander1 aDeshmukh, Gunvant1 aSubramani, Kumar1 aKrueger, Bastian1 aHaensch, Mareike1 aSchwenzel, Julian1 aKrishnamoorthy, Kothandam1 aWittstock, Gunther uhttps://library.ncl.res.in/content/effect-aromatic-rings-and-substituent-performance-lithium-batteries-rylene-imide-cathodes02281nas a2200229 4500008004100000022001400041245012600055210006900181260000900250300001600259490000700275520144800282653002001730653002101750100002201771700001901793700002501812700002801837700003001865700002401895856013201919 2023 eng d a1477-922600aElectrocatalytic hydrogen evolution mediated by an organotelluroxane macrocycle stabilized through secondary interactions0 aElectrocatalytic hydrogen evolution mediated by an organotelluro cNOV  a17242-172480 v523 a

A discrete liphophilic organotelluroxane macrocycle has been found to catalyse the hydrogen evolution reaction (HER) by proton reduction efficiently. The macrocycle is synthesized via chloride abstraction from bis(p-methoxyphenyl) tellurium dichloride (p-MeOC6H5)2TeCl2 (1) by silver salts AgMX4 (MX4 = BF4-, and ClO4-) resulting in in situ generated di-cationic tetraorganoditelluroxane units; two such units are held together by two weak anions mu 2-MX4, bridging to form 12-membered di-cationic macrocycles [((p-MeO-C6H4)2Te)2(mu-O)(mu 2-F2BF2)2]2+ (2) and [((p-MeO-C6H4)2Te)2(mu-O)(mu 2-O2ClO2)2]2+ (3) stabilized via Te-(mu 2-BF4/ClO4), with secondary interactions. The charge is balanced by the presence of two more anions, one above and another below the plane of the macrocycle. Similar reaction at higher temperatures leads to the formation of telluronium salts R3TeX [X = BF4- (4), ClO4- (5)] as a major product. The BF4- anion containing macrocycle and telluronium salt were monitored using 19F NMR. HRMS confirmed the structural stability of all the compounds in the solution state. The organotelluroxane macrocycle 2 has been found to act as an efficient electrocatalyst for proton reduction in an organic medium in the presence of p-toluene sulfonic acid as a protic source. A discrete liphophilic organotelluroxane macrocycle has been found to catalyse hydrogen evolution reaction (HER) by proton reduction efficiently.

10aAnion Transport10aProton-Reduction1 aNarsimhulu, Gujju1 aSamuel, Calvin1 aPalani, Sathishkumar1 aDasari, Sai, Hemant Kum1 aKrishnamoorthy, Kothandam1 aBaskar, Viswanathan uhttps://library.ncl.res.in/content/electrocatalytic-hydrogen-evolution-mediated-organotelluroxane-macrocycle-stabilized-through03030nas a2200205 4500008004100000022001400041245018300055210006900238260000800307300001600315490000600331520222200337100001802559700002702577700001702604700001702621700003002638700002702668856012902695 2024 eng d a2470-134300aEffect of position of donor units and alkyl groups on dye-sensitized solar cell device performance: indoline-aniline donor-based visible light active unsymmetrical squaraine dyes0 aEffect of position of donor units and alkyl groups on dyesensiti cMAR a16429-164420 v93 a

Indoline (In) and aniline (An) donor-based visible light active unsymmetrical squaraine (SQ) dyes were synthesized for dye-sensitized solar cells (DSSCs), where the position of An and In units was changed with respect to the anchoring group (carboxylic acid) to have In-SQ-An-CO2H and An-SQ-In-CO2H sensitizers, AS1-AS5. Linear or branched alkyl groups were functionalized with the N atom of either In or An units to control the aggregation of the dyes on TiO2. AS1-AS5 exhibit an isomeric pi-framework where the squaric acid unit is placed in the middle, where AS2 and AS5 dyes possess the anchoring group connected with the An donor, and AS1, AS3, and AS4 dyes having the anchoring group connected with the In donor. Hence, the conjugation between the middle squaric acid acceptor unit and the anchoring -CO2H group is short for AS2, AS5, and AK2 and longer for AS1, AS3, and AS4 dyes. AS dyes showed absorption between 501 and 535 nm with extinction coefficients of 1.46-1.61 x 10(5) M-1 cm(-1). Further, the isomeric pi-framework of An-SQ-In-CO2H and In-SQ-An-CO2H exhibited by means of changing the position of In and An units a bathochromic shift in the absorption properties of AS2 and AS5 compared to the AS1, AS3, and AS4 dyes. The DSSC device fabricated with the dyes contains short acceptor-anchoring group distance (AS2 and AS5) showed high photovoltaic performances compared to the dyes having longer distance (AS1, AS3, and AS4) with the iodolyte (I-/I-3(-)) electrolyte. DSSC device efficiencies of 5.49, 6.34, 6.16, and 5.57% have been achieved for AS1, AS2, AS3, and AS4 dyes, respectively; without chenodeoxycholic acid (CDCA), small changes have been observed in the device performance of the AS dyes with CDCA. Significant changes have been noted in the DSSC parameters (open-circuit voltage V-OC, short-circuit current J(SC), fill factor ff, and efficiency eta) for the AS5 dye while sensitized with CDCA and showed highest DSSC efficiency of 8.01% in the AS dye series. This study revealed the potential of shorter SQ acceptor-anchoring group distance over the longer one and the importance of alkyl groups on the overall DSSC device performance for the unsymmetrical squaraine dyes.

1 aSingh, Amrita1 aSingh, Ambarish, Kumar1 aDixit, Ruchi1 aVanka, Kumar1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/effect-position-donor-units-and-alkyl-groups-dye-sensitized-solar-cell-device-performance03071nas a2200277 4500008004100000022001400041245013500055210006900190260000900259300001400268490000600282520203300288653002402321653002502345653003102370653003502401653005202436100002402488700002702512700002702539700001602566700002602582700003002608700002702638856012802665 2025 eng d a2574-096200aEffect of cyclization and alkyl group wrapping in visible-light-active unsymmetrical squaraine dyes for dye-sensitized solar cells0 aEffect of cyclization and alkyl group wrapping in visiblelightac cAPR  a5017-50300 v83 a

A series of alkyl group-appended indoline- and carboxylic acid-functionalized indolenine-based visible-light-active unsymmetrical squaraine dyes, SQA7-10, were designed, synthesized, and utilized for the dye-sensitized solar cells device fabrication. The number of alkyl group has been increased systematically on the indoline moiety to control the self-assembly of dyes on TiO2 and to passivate the photoanode that helps in improving the open-circuit voltage (V-OC) by avoiding the charge recombination process. SQA7-10 dyes showed an absorption between lambda(max) 536-540 nm, with molar extinction coefficients of 1.62-2.13 x 10(5) M-1 cm(-1) in CH3CN. Further, ultraviolet-visible (UV-vis) studies on TiO2 indicated the formation of H-aggregated dyes (505-510 nm), which can be controlled by appending the alkyl groups. The energy levels of the highest occupied molecular orbital (HOMO) of these dyes are well aligned with the Nernst potentials of I-/I(3)(-)electrolyte and [Cu(tmby)(2)](+/2+) electrolytes with sufficient overpotentials required for the dye regeneration process. DSSC devices made with these dyes showed systematic enhancements of open-circuit voltage (V-OC) and device efficiency with respect to alkyl group incorporation for SQA7-10 with I-/I-3(-) electrolytes. All of the SQA dyes exhibited the device V-OC of more than 805 mV, where the introduction of alkyl groups systematically enhanced the V-OC in the order of SQA7 (805 mV) < SQA8 (829 mV) < SQA9 (843 mV) < SQA10 (862 mV) without any addition of CDCA. Within the SQA dye series, SQA10 dye has achieved the highest DSSC device efficiency of 7.52% (J(sc) of 11.16 mA/cm(2), V-oc of 862 mV, and ff of 78%) with I-/I-3(-) electrolyte, whereas use of [Cu(tmby)(2)](+/2+) redox shuttle with SQA10 showed enhanced V-oc (1080 mV) and device efficiency (8.35%). The IPCE profile for the device fabricated with SQA dyes showed good response at 480 and 560 nm, which indicates the photocurrent generation from the aggregated structures.

10aaggregation of dyes10acharge recombination10aDye-sensitized solar cells10aindoline and indolenine donors10avisible-light-activeunsymmetrical squaraine dye1 aJadhav, Avinash, P.1 aSingh, Ambarish, Kumar1 aShivankar, Bhavana, R.1 aSiby, Jesna1 aKrishnamurty, Sailaja1 aKrishnamoorthy, Kothandam1 aNithyanandhan, Jayaraj uhttps://library.ncl.res.in/content/effect-cyclization-and-alkyl-group-wrapping-visible-light-active-unsymmetrical-squaraine