02250nas a2200193   4500008004100000022001400041245013100055210006900186260007100255300001600326490000800342520147800350100001901828700001801847700001601865700003001881700002101911856012401932       2015                        eng d  a1932-744700aSynthesis, optoelectronic, and transistor properties of BODIPY- and cyclopenta[c]thiophene-containing pi-conjugated copolymers0 aSynthesis optoelectronic and transistor properties of BODIPY and  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL  a15859-158670 v1193 a<p>Three new low-band-gap copolymers were synthesized by fusing dipyrromethene difluoroborane (BODIPY) as the acceptor (A) and thiophene-capped 5,5-bis(hexyloxymethyl)-5,6-dihydro-4H-cyclopenta[c]-thiophene (CPT) as the donor (D). The BODIPY unit was copolymerized through the `alpha' positions (1 and 7 positions) in P1 and through the `beta' positions (2 and 6 positions) in P2 and P3. The additional acetylene unit between D and A in P3 enhanced the conjugation by minimizing the possible steric hindrance compared to that in P2, whereas P1 exhibited a more red-shifted absorption than P2 and P3 because of the more effective conjugaion through the `alpha' positions of BODIPY. Importantly, the optical band gaps (E-g(opt)) obtained from the onset of the absorption spectra are 1.28, 1.71, and 1.57 eV for P1, P2, and P3, respectively. P1 has the lowest band gap for any CPT-containing polymer. In the best transistor devices, a mobility improvement by 4 orders of magnitude from 3.22 x 10(-6) cm(2) V-1 s(-1) for P2 to 0.01 cm(2) V-1 s(-1) for P1 was achieved. DFT calculations alongside measured charge-transport properties indicated that appreciable alterations in the optoelectronic properties of the polymers were achieved through minor changes in their structural features. The polymers were further characterized by thin-film X-ray diffraction, atomic force microscopy, and spectroelectrochemistry to investigate their material and electrochemical properties.</p>1 aDebnath, Sashi1 aSingh, Saumya1 aBedi, Anjan1 aKrishnamoorthy, Kothandam1 aZade, Sanjio, S.  uhttps://library.ncl.res.in/content/synthesis-optoelectronic-and-transistor-properties-bodipy-and-cyclopentacthiophene-102037nas a2200193   4500008004100000245013800041210006900179260000800248300001600256490000600272520131300278100001901591700002801610700001801638700001601656700003001672700002101702856012001723       2016                        eng d00aSelenium-containing fused bicyclic heterocycle diselenolodiselenole: field effect transistorstudy and structure property relationship0 aSeleniumcontaining fused bicyclic heterocycle diselenolodiseleno  cJUL  a18222-182300 v83 aThe first application of the diselenolodiselenole (C4Se4) heterocycle as an active organic field effect transistor materials is demonstrated here. C4Se4 derivatives (2a-2d) were obtained by using a newly developed straightforward diselenocyclization protocol, which includes the reaction of diynes with selenium powder at elevated temperature. C4Se4 derivatives exhibit strong donor characteristics and planar structure (except 2d). The atomic force microscopic analysis and thin-film X-ray diffraction pattern of compounds 2a-2d indicated the formation of distinct crystalline films that contain large domains. A scanning electron microscopy study of compound 2b showed development of symmetrical grains with an average diameter of 150 nm. Interestingly, 2b exhibited superior hole mobility, approaching 0.027 cm(2) V-1 s(-1) with a transconductance of 9.2 mu S. This study correlate the effect of p-stacking, Se center dot center dot center dot Se intermolecular interaction, and planarity with the charge transport properties and performance in the field effect transistor devices. We have shown that the planarity in C4Se4 derivatives was achieved by varying the end groups attached to the C4Se4 core. In turn, optoelectronic properties can also be tuned for all these derivatives by end-group variation.1 aDebnath, Sashi1 aChithiravel, Sundaresan1 aSharma, Sagar1 aBedi, Anjan1 aKrishnamoorthy, Kothandam1 aZade, Sanjio, S.  uhttps://library.ncl.res.in/content/selenium-containing-fused-bicyclic-heterocycle-diselenolodiselenole-field-effect02081nas a2200241   4500008004100000022001400041245011300055210006900168260006700237300001400304490000700318520123700325653001401562653001101576653000801587653001701595100001901612700001801631700001601649700003001665700002101695856012301716       2016                        eng d  a0887-624X00aSite-selective synthesis and characterization of BODIPY-acetylene copolymers and their transistor properties0 aSiteselective synthesis and characterization of BODIPYacetylene   a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcJUL  a1978-19860 v543 a<p>To study the effect of site-selective copolymerization of borondipyrromethene (BODIPY) with acetylene on the structural and optoelectronic properties, three copolymers P1-P3 were synthesized by the Sonogashira cross-coupling of BODIPY units with diacetylene and bromine capping through all the possible linkages: alpha-alpha (P1), alpha-beta (P2), and beta-beta (P3). The optoelectronic properties of the polymers were investigated systematically to understand the effect of site-selective polymerization. The HOMO levels of the polymers were significantly tuned from P1 to P3 with negligible change in the LUMO levels. Broadening of absorption spectra from P3 to P1 was observed because of increase in the extent of conjugation. Additionally, the charge transport properties of these polymers in organic thin-film transistors (OTFTs) revealed that P1 and P3 exhibited only p-type mobility, whereas P2 exhibited electron mobility. Notably, the further investigations of the surface morphology of polymer films by atomic force microscopy (AFM) unveiled that comb like nanostructural arrangements in P3 was beneficial for the charge-carrier mobility over the circular arrangements in P1 and P2. (C) 2016 Wiley Periodicals, Inc.</p>10aacetylene10aBODIPY10aDFT10alow-band gap1 aDebnath, Sashi1 aSingh, Saumya1 aBedi, Anjan1 aKrishnamoorthy, Kothandam1 aZade, Sanjio, S.  uhttps://library.ncl.res.in/content/site-selective-synthesis-and-characterization-bodipy-acetylene-copolymers-and-their