摘要 :
A new electrontransport polymer, poly{[N,N'-dioctylperylene-3,4,9,10-bis(dicarb-oximide)-1 ,7(6)-diyl]-o/t-[(2,5-bis(2-ethyl-hexyl)-1 ,4-phenylene)bis(ethyn-2,1 -diyl]} (PDIC8-EB), is synthesized. In chloroform, the polymer underg...
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A new electrontransport polymer, poly{[N,N'-dioctylperylene-3,4,9,10-bis(dicarb-oximide)-1 ,7(6)-diyl]-o/t-[(2,5-bis(2-ethyl-hexyl)-1 ,4-phenylene)bis(ethyn-2,1 -diyl]} (PDIC8-EB), is synthesized. In chloroform, the polymer undergoes self-assembly, forming a nanowire suspension. The nanowire's optical and electrochemical properties, morphological structure, and field-effect transistor (FET) characteristics are investigated. Thin films fabricated from a PDIC8-EB nanowire suspension are composed of ordered nanowires and ordered and amorphous non-nanowire phases, whereas films prepared from a homogeneous PDIC8-EB solution consist of only the ordered and amorphous non-nanowire phases. X-ray scattering experiments suggest that in both nanowires and ordered phases, the PDIC8 units are laterally stacked in an edge-on manner with respect to the film plane, with full interdigitation of the octyl chains, and with the polymer backbones preferentially oriented within the film plane. The ordering and orientations are significantly enhanced through thermal annealing at 200 °C under inert conditions. The polymer film with high degree of structural ordering and strong orientation yields a high electron mobility (0.10 + 0.05 cm~2 V~(-1) s~(-1)), with a high on/off ratio (3.7 × 106), a low threshold voltage (8 V), and negligible hysteresis (0.5 V). This study demonstrates that the polymer in the nanowire suspension provides a suitable material for fabricating the active layers of high-performance n-channel FET devices via a solution coating process.
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摘要 :
Siloles are attractive building blocks for the design and synthesis of organic semiconductors that exhibit potential applications in light-emitting diodes, solar cells, field-effect transistors, and sensors. Understanding how mole...
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Siloles are attractive building blocks for the design and synthesis of organic semiconductors that exhibit potential applications in light-emitting diodes, solar cells, field-effect transistors, and sensors. Understanding how molecular engineering of the electronic structures can help control the properties of these materials has attracted significant research effort. In the present review we illustrate the current state-of-the-art of the molecular engineering of siloles, especially focusing on the effects of substituents and on the electronic structure of siloles.
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摘要 :
Photoemission spectroscopy is used to probe the electronic properties, reactivity and energy level alignment at interfaces of tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thie-no}[3,4-b,h,n]-1 ,4,5,8,9,12-hexaazatriphenylene (THAP...
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Photoemission spectroscopy is used to probe the electronic properties, reactivity and energy level alignment at interfaces of tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thie-no}[3,4-b,h,n]-1 ,4,5,8,9,12-hexaazatriphenylene (THAP) deposited on both medium and high work function metallic substrates. Crystalline and non-crystalline metal substrates are used in order to investigate the effect of both the work function and molecular orientation on the physical properties of the THAP layer.
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摘要 :
N-Doping of copper phthalocyanine (CuPc), which has an electron affinity (EA) of 3.52 eV, by decamethylcobaltocene (DMC) is demonstrated. DMC has a remarkably low solid-state ionization energy (IE) of 3.3 eV, as measured by ultra-...
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N-Doping of copper phthalocyanine (CuPc), which has an electron affinity (EA) of 3.52 eV, by decamethylcobaltocene (DMC) is demonstrated. DMC has a remarkably low solid-state ionization energy (IE) of 3.3 eV, as measured by ultra-violet photoemission spectroscopy (UPS). Further UPS measurements show a large 1.4 eV upward shift of the Fermi-level within the single particle gap of CuPc between the p- and n-doped films. n-Doping is also confirmed by current-voltage (I-V) measurements, which show a 10~6-fold increase in current density due to improved electron injection and enhanced conductivity of the bulk film. An organic p-i-n CuPc homojunction is also fabricated using F_4-TCNQ and DMC as p- and n-dopants, respectively. Current-voltage characteristics demonstrate excellent rectification with a turn on voltage of approximately 1.3 eV, which is consistent with the built-in voltage measured by UPS and capacitance-voltage (C-V) measurements.
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摘要 :
Layer-by-layer growth of the electron-transport material tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thieno} [3,4-b,h,n]-l,4,5,8,9,12-hexaazatriphenylene (THAP) on Au(111) is probed by scanning tunneling microscopy (STM). A relat...
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Layer-by-layer growth of the electron-transport material tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thieno} [3,4-b,h,n]-l,4,5,8,9,12-hexaazatriphenylene (THAP) on Au(111) is probed by scanning tunneling microscopy (STM). A relative of discotic liquid crystalline molecules, THAP is shown to grow in commensurate ordered planes from the first to fourth monolayers. The four monolayers all show a concordant ordered structure in which the molecules arrange parallel to the substrate in a hexagonal close-packed lattice with a herringbone pattern defined by alternating rows of molecules with antiparallel orientation. The unit cell is rectangular with two molecules per cell and is nearly equivalent for each layer. The spatial broadening of the local density of states due to the metallic substrate is appreciably diminished in upper layers, as expected and as evidenced by the localization of states seen in STM. There is good agreement between the highest occupied molecular orbital obtained in density functional theory calculations for a single molecule and STM images of the upper layers, in accord with the localized nature of electronic states on molecules under minimal substrate influence.
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摘要 :
This work focuses on organic-organic heterojunctions (OOHs) formed between two small-molecule, low band-gap, semiconductors, tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thieno}[3,4-b,h,n]-l ,4,5,8,9,12 -hexaaza-triphenylene (THAP...
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This work focuses on organic-organic heterojunctions (OOHs) formed between two small-molecule, low band-gap, semiconductors, tris{2,5-bis(3,5-bis-trifluoromethyl-phenyl)-thieno}[3,4-b,h,n]-l ,4,5,8,9,12 -hexaaza-triphenylene (THAP), and copper phthalocyan
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摘要 :
The synthesis and X-ray characterization of two new dialkynylated diazatetracenes and the corresponding N,N-dihydrodiazatetracenes are reported. The dialkynylated heteroacenes are packed in a brick-wall motif that enforces signifi...
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The synthesis and X-ray characterization of two new dialkynylated diazatetracenes and the corresponding N,N-dihydrodiazatetracenes are reported. The dialkynylated heteroacenes are packed in a brick-wall motif that enforces significant overlap of their jr-
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摘要 :
Electrical or chemical doping of molecular films is an efficient means of improving and controlling charge injection and carrier transport in organic devices. Recent work demonstrated that bis(cyclopentadienyl)cobalt(II) (cobaltoc...
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Electrical or chemical doping of molecular films is an efficient means of improving and controlling charge injection and carrier transport in organic devices. Recent work demonstrated that bis(cyclopentadienyl)cobalt(II) (cobaltocene, CoCp_2) efficiently dopes a
tris(thieno)hexaazatriphenylene (THAP) derivative, as shown by a 0.56 eV shift of the Fermi level toward the empty states and an increase of current density by a factor of 10~3 over undoped THAP devices. In this work, a combination of x-ray photoemission spectroscopy and Rutherford backscattering is used to elucidate the details of dopant incorporation into bulk films. Cobaltocene is observed to codeposit into the THAP matrix in a controllable manner, with preferential adsorption of the dopant onto the surface of the host film. In the case of CoCp_2-doped tris(8-hydroxy-quinolinato) aluminum (Alq_3) films, negligible amounts of the dopant are found in the bulk matrix and on the film surface, resulting in minimal improvements in the electrical characteristics of doped Alq_3 films. The process of CoCp_2 adsorption onto a film surface or the evolving surface of a growing film which leads to dopant incorporation is likely assisted by charge transfer from cobaltocene to the host material, resulting in ion pairing between the dopant and host.
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摘要 :
Ozonolysis of the 2,6-divinyl derivative of a
naphthalene diimide (NDI) affords a 2,6-diformyl-NDI, which
can be used in Knoevenagel condensation reactions, as
demonstrated by the synthesis of a 2,6-bis(2,2-dicyanovinyl)-
NDI. UV−...
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Ozonolysis of the 2,6-divinyl derivative of a
naphthalene diimide (NDI) affords a 2,6-diformyl-NDI, which
can be used in Knoevenagel condensation reactions, as
demonstrated by the synthesis of a 2,6-bis(2,2-dicyanovinyl)-
NDI. UV−vis absorption and electrochemical data are
compared to those of the parent NDI.
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摘要 :
A narrow band-gap alternating copolymer of perylene diimide and bis(dithienothiophene) (2) and a polythiophene derivative substituted by a tris(thienylenevinylene) conjugated side chain (4) are used as acceptor and donor, respecti...
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A narrow band-gap alternating copolymer of perylene diimide and bis(dithienothiophene) (2) and a polythiophene derivative substituted by a tris(thienylenevinylene) conjugated side chain (4) are used as acceptor and donor, respectively, in all-polymer solar cells (SCs). The optimized device based on the blend of 4 and 2 in the ratio 3:1 (w/w) gives a short circuit current (J_(sc)) of 5.02 mA cm~(-2) and a power conversion efficiency of 1.48%, under simulated AM 1.5 illumination at 100 mW cm~(-2). These values are among the highest values reported for all-polymer SCs.
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