Current methods of synthesizing single-walled carbon nanotubes(SWNTs)result in racemic mixtures that have impeded the study of left-and right-handed SWNTs.Here we present a method of isolating different SWNT enantiome...Current methods of synthesizing single-walled carbon nanotubes(SWNTs)result in racemic mixtures that have impeded the study of left-and right-handed SWNTs.Here we present a method of isolating different SWNT enantiomers using density gradient ultracentrifugation.Enantiomer separation is enabled by the chiral surfactant sodium cholate,which discriminates between left-and right-handed SWNTs and thus induces subtle differences in their buoyant densities.This sorting strategy can be employed for simultaneous enrichment by handedness and roll-up vector of SWNTs having diameters ranging from 0.7 to 1.5 nm.In addition,circular dichroism of enantiomer refined samples enables identification of high-energy optical transitions in SWNTs.展开更多
A series of polymer photodetectors with device configuration of ITO/PEDOT:PSS/P_(3)HT:PC_(61)BM/C_(60)/AI were prepared by using P3HT as the donor material and PC61BM as the acceptor material.By regulating the content...A series of polymer photodetectors with device configuration of ITO/PEDOT:PSS/P_(3)HT:PC_(61)BM/C_(60)/AI were prepared by using P3HT as the donor material and PC61BM as the acceptor material.By regulating the content of 1,8-diiodooctane(DIO)(V/V:1%,3%,5%)as a processing additive,the morphology of the active layer can be greatly improved With Ceo as the hole blocking layer,the dark current density of the device can be reduced by about an order of magnitude.When employing 3%DIO(V/V)in the active layer processing,the photodetetcors present the best performance,and the detectivity of the device is 1.52×10^(12)Jones at 540 nm under a bias of-0.1 V.Moreover,it also has a wider linear dynamic range of 60 dB as well as faster response speed(T1/T2=0.53/0.71μs)than those of devices with other content of DIO additives.展开更多
基金The authors thank M.S.Arnold for helpful discussions and preliminary measurements.This work was supported by the U.S.Army Telemedicine and Advanced Technology Research Center(DAMD17-05-1-0381)the National Science Foundation(DMR-0520513,EEC-0647560,and DMR-0706067)A Natural Sciences and Engineering Research Council of Canada Postgraduate Scholarship(A.A.Green)and an Alfred P.Sloan Research Fellowship(M.C.Hersam)are also acknowledged.This work made use of instruments in the Keck-II facility of the NUANCE Center and the Keck Biophysics Facility at Northwestern University.The NUANCE Center is supported by NSF-NSEC,NSF-MRSEC,Keck Foundation,the State of Illinois,and Northwestern University.
文摘Current methods of synthesizing single-walled carbon nanotubes(SWNTs)result in racemic mixtures that have impeded the study of left-and right-handed SWNTs.Here we present a method of isolating different SWNT enantiomers using density gradient ultracentrifugation.Enantiomer separation is enabled by the chiral surfactant sodium cholate,which discriminates between left-and right-handed SWNTs and thus induces subtle differences in their buoyant densities.This sorting strategy can be employed for simultaneous enrichment by handedness and roll-up vector of SWNTs having diameters ranging from 0.7 to 1.5 nm.In addition,circular dichroism of enantiomer refined samples enables identification of high-energy optical transitions in SWNTs.
文摘A series of polymer photodetectors with device configuration of ITO/PEDOT:PSS/P_(3)HT:PC_(61)BM/C_(60)/AI were prepared by using P3HT as the donor material and PC61BM as the acceptor material.By regulating the content of 1,8-diiodooctane(DIO)(V/V:1%,3%,5%)as a processing additive,the morphology of the active layer can be greatly improved With Ceo as the hole blocking layer,the dark current density of the device can be reduced by about an order of magnitude.When employing 3%DIO(V/V)in the active layer processing,the photodetetcors present the best performance,and the detectivity of the device is 1.52×10^(12)Jones at 540 nm under a bias of-0.1 V.Moreover,it also has a wider linear dynamic range of 60 dB as well as faster response speed(T1/T2=0.53/0.71μs)than those of devices with other content of DIO additives.
