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<p>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.</p>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-002592nas 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<p>
	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</p>
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