02552nas a2200169   4500008004100000022001400041245012900055210006900184260011000253300001600363490000700379520179700386100001802183700002302201700003002224856012802254       2014                        eng d  a1463-907600aOrganic soluble and uniform film forming oligoethylene glycol substituted BODIPY small molecules with improved hole mobility0 aOrganic soluble and uniform film forming oligoethylene glycol su  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY  a13376-133820 v163 a<p>Judiciously chosen side chains of conjugated molecules have a positive impact on charge transport properties when used as the active material in organic electronic devices. Amongst the side chains, oligoethylene glycols (OEGs) have been relatively unexplored due to their hydrophilic nature. OEGs also affect the smooth film formation of conjugated molecules, which preclude device fabrication. However, X-ray diffraction studies have shown that OEGs facilitate intermolecular contact, which is a desirable property for the fabrication of organic electronic devices. Thus the challenge is to design and synthesize organic solvent soluble and uniform film forming conjugated molecules with OEG side chains. We have designed and synthesized conjugated small molecules (CSMs) comprising BODIPY as acceptor and triphenylamine as donor with an OEG side chain. This molecule forms smooth films when processed from organic solvents. In order to understand the impact of the OEG side chain, we have also synthesized alkyl chain analogs. All the molecules exhibit exactly the same HOMO and LUMO energy levels, but the packing in the solid state is different. CSM with methyl side chains exhibit an inter planar distance of 4.15 A. Contrary to this, the OEG side chain containing CSM showed an inter planar spacing of 4.30 A, which is 0.2 A less than the alkyl side chain comprising CSMs. Please note that the length of the hydrophobic and hydrophilic side chains is the same. Interestingly, the OEG side chain comprising CSM showed two orders of higher hole carrier mobilities compared to all the other derivatives. The same molecule also showed an extremely low threshold voltage of -0.27 V indicating the OEG side chains' favourable interaction between substrate as well as between molecules.</p>1 aSingh, Saumya1 aVenugopalan, Vijay1 aKrishnamoorthy, Kothandam  uhttps://library.ncl.res.in/content/organic-soluble-and-uniform-film-forming-oligoethylene-glycol-substituted-bodipy-small-001448nas a2200169   4500008004100000245011300041210006900154260000800223300001200231490000800243520079400251100002601045700002901071700002601100700002301126856012901149       2017                        eng d00aInfluence of thermocleavable functionality on organic field-effect transistor performance of small molecules0 aInfluence of thermocleavable functionality on organic fieldeffec  cJUN  a139-1450 v6783 aDiketopyrrolopyrrole based donor-acceptor-donor conjugated small molecules using ethylene dioxythiophene as a donor was synthesized. Electron deficient diketopyrrolopyrrole unit was substituted with thermocleavable (tert-butyl acetate) side chains. The thermal treatment of the molecules at 160 degrees C eliminated the tert-butyl ester group results in the formation of corresponding acid. Optical and theoretical studies revealed that the molecules adopted a change in molecular arrangement after thermolysis. The conjugated small molecules possessed p-channel charge transport characteristics in organic field effect transistors. The charge carrier mobility was increased after thermolysis of tert-butyl ester group to 5.07 x 10(-5) cm(2)/Vs. (C) 2017 Elsevier B.V. All rights reserved.1 aMahale, Rajashree, Y.1 aDharmapurikar, Satej, S.1 aChini, Mrinmoy, Kumar1 aVenugopalan, Vijay  uhttps://library.ncl.res.in/content/influence-thermocleavable-functionality-organic-field-effect-transistor-performance-small02131nas a2200253   4500008004100000245010800041210006900149260000800218300001400226490000600240520124600246653001901492653002501511653002601536653002301562653002301585653002701608100002301635700002201658700002601680700002101706700003001727856012001757       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  uhttps://library.ncl.res.in/content/instabilities-origin-large-area-self-assembled-and-aligned-organic-semiconductor