02130nas a2200253   4500008004100000245010800041210006900149260000800218300001400226490000600240520124600246653001901492653002501511653002601536653002301562653002301585653002701608100002301635700002201658700002601680700002101706700003001727856011901757       2022                        eng d00aInstabilities as the origin of large-area self-assembled and aligned organic semiconductor nanocrystals0 aInstabilities as the origin of largearea selfassembled and align  cAPR  a1815-18220 v43 a<p>
	Aligned nanocrystals of organic semiconductors (OSCs) are highly desirable for electronic devices and biomedical and photonic applications. Solution-based wet processing routes have the potential to produce aligned nanocrystals over large areas in small time frames. Herein, we demonstrate that by optimizing the hydrodynamic evaporative processes, controlled long-range crystalline assemblies of OSCs can be achieved (longest nanocrystal similar to 3 mm) purely through physical processes: namely, from fingering instabilities. Self-assembly is achieved here without strong noncovalent interactions such as hydrogen-bonding interactions. Experimentally our approach involves just placing a drop of a solution on an inclined substrate. Nanocrystals with widths of 300-800 nm and lengths of millimeters (length/width aspect ratios &gt;10(5)) are formed in less than 2-8 s. A hydrazine chemiresistive sensor based on the aligned crystalline patterns show unprecedented responsivity (similar to 10(-6)), 2 orders greater than those of stick-slip patterns. Finally, experimental parameters that need optimization to achieve nanocrystal patterns are investigated in detail and pointers to fabricate such OSC nanocrystals are provided.</p>
10aaligned fibers10adiketopyrrolopyrrole10afingering instability10ananocrystal arrays10anaphthalenediimide10aorganic semiconductors1 aVenugopalan, Vijay1 aJain, Bhanprakash1 aMahale, Rajashree, Y.1 aSubramani, Kumar1 aKrishnamoorthy, Kothandam  uhttp://library.ncl.res.in/content/instabilities-origin-large-area-self-assembled-and-aligned-organic-semiconductor02591nas a2200205   4500008004100000022001400041245011800055210006900173260000900242520181500251653002502066653003602091653001902127653002702146653002002173100002102193700002102214700002402235856012602259       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.  uhttp://library.ncl.res.in/content/variations-packing-function-side-chains-random-copolymers-and-its-impact-charge-carrier