01979nas a2200181   4500008004100000022001400041245016000055210006900215260007100284300001600355490000800371520120400379100002201583700001701605700003101622700002001653856012401673       2010                        eng d  a1520-610600aN-Type field effect transistors based on rigid rod and liquid crystalline alternating copoly(benzobisoxazole) imides containing perylene and/or naphthalene0 aNType field effect transistors based on rigid rod and liquid cry  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcDEC  a16694-167040 v1143 a<p>The synthesis, characterization, and device studies of poly(benzobisoxazole imide)s containing perylene or naphthalene units in an alternating fashion with the oxazole unit are described. Photoinduced energy transfer and charge separation were studied in methanesulfonic acid (MSA) solution via absorption, excitation, and steady-state fluorescence studies. Excitation of the bisoxazole moiety resulted in enhanced emission from the perylene bisimide unit as a result of FRET (Forster resonance energy transfer). The influence of the imide substitution into the linear chain of poly(benzobisoxazole) (PBO) on its solid-state packing was examined by wide-angle X-ray diffraction (WXRD) analysis. Bottom contact field effect transistors (FET) based on thermally annealed polymer films were fabricated and studied. The polymers showed n-type charge transport and current modulation with an on/off ratio greater than 10(2). It was observed that the FETs consisting of the random copolymer of bisoxazole containing both perylene as well as naphthalene bisimide units had higher performance parameters such as better mobility (mu e) and I(on)/I(off) ratio compared to those of the pristine systems.</p>1 aKolhe, Nagesh, B.1 aAsha, S., K.1 aSenanayak, Satyaprasad, P.1 aNarayan, K., S.  uhttps://library.ncl.res.in/content/n-type-field-effect-transistors-based-rigid-rod-and-liquid-crystalline-alternating-002611nas a2200205   4500008004100000022001400041245013600055210006900191260011000260300001600370490000700386520175900393100002202152700001802174700003102192700001402223700002002237700001702257856013102274       2012                        eng d  a0959-942800aStructure engineering of naphthalene diimides for improved charge carrier mobility: self-assembly by hydrogen bonding, good or bad?0 aStructure engineering of naphthalene diimides for improved charg  aTHOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLANDbROYAL SOC CHEMISTRYcMAY  a15235-152460 v223 a<p>Two families of naphthalene diimide (NDI) derivatives were compared and contrasted for the effect of self-assembly on charge carrier transport. One series of NDI derivatives had a terminal phenyl ring attached to a hexyl spacer substituted naphthalene core either through an ester or an amide linkage (NDI-E and NDI-A, respectively), while the other series had a 3,4,5-tridodecyloxy phenyl unit (NDI-E3, NDI-A3) instead of the terminal phenyl unit. Solution processed thin films of these molecules exhibited n-type charge transport characteristics in a bottom gate top contact organic field effect transistor (OFET) geometry. The amide derivatives showed evidence of self-organization with observation of red shifted aggregate emission in solution as well as solid state. Variable temperature FTIR studies in the solid state confirmed the existence of strong hydrogen bonding which could be broken only at very high temperature. However, contrary to expectations, the NDI ester derivatives showed better device efficiency with electron mobilities in the range 8.5 x 10(-3) to 2 x 10(-2) cm(2) V-1 s(-1) and on/off ratio similar to 10(4). The thin film crystallinity and morphology of NDI-E and NDI-A were examined through X-ray diffraction and atomic force microscopy (AFM). The correlation of crystallinity, hydrogen bonding and charge carrier mobility was studied using energy minimized structures from density functional theory (DFT). The higher electron mobility of ester linked NDI derivatives over the amide linked ones was attributed to the freedom in charge transport pathways offered by a three dimensional crystalline organization in the ester compared to the restricted directional hydrogen bonding interaction in the amide derivatives.</p>1 aKolhe, Nagesh, B.1 aDevi, Nandini1 aSenanayak, Satyaprasad, P.1 aJancy, B.1 aNarayan, K., S.1 aAsha, S., K.  uhttps://library.ncl.res.in/content/structure-engineering-naphthalene-diimides-improved-charge-carrier-mobility-self-assembly-0