@article { ISI:000323241100045,
	title = {Enhanced hole carrier transport due to increased intermolecular contacts in small molecule based field effect transistors},
	journal = {ACS Applied Materials \& Interfaces},
	volume = {5},
	number = {15},
	year = {2013},
	month = {AUG},
	pages = {7086-7093},
	publisher = {AMER CHEMICAL SOC},
	address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
	abstract = {<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>},
	keywords = {hole mobility, i-indigo, organic field effect transistor, quadrupole interaction, small molecules, triphenylamine},
	issn = {1944-8244},
	doi = {10.1021/am401379a},
	author = {Dharmapurikar, Satej S. and Arulkashmir, Arulraj and Das, Chayanika and Muddellu, Pooja and Krishnamoorthy, Kothandam}
}
@article {49402,
	title = {Variations in packing as a function of side chains in random copolymers and its impact on charge carrier mobility},
	journal = {Macromolecular Chemistry and Physics},
	year = {2024},
	month = {OCT },
	type = {Article; Early Access},
	abstract = {<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>
},
	keywords = {diketopyrrolopyrrole, organic field effect transistor, random polymer, side chain engineering, thienoisoindigo},
	issn = {1022-1352},
	doi = {10.1002/macp.202400294},
	author = {Swain, Gitanjali and Kumar, Subramani and Samudre, Nikhil S.}
}
