To search for more wider absorption and higher charge carriers mobilities materials of polymer solar cell, a series of soluble alternating polyfluorene copolymers were synthesized by palladium-catalyzed Suzuki couplin...To search for more wider absorption and higher charge carriers mobilities materials of polymer solar cell, a series of soluble alternating polyfluorene copolymers were synthesized by palladium-catalyzed Suzuki coupling reaction. Their structures were determined by 1H NMR, IR and UV-vis. And their UV-vis absorption spectra indicated that they had strong absorption over 600 nm spectral range and nearly cover 400-700 nm visible region. The band gaps of copolymers calculated according to cyclic voltammetry （CV） were between 1.96 and 2.03 eV. Polymer：TiO2 bulk-heterojunction films were made from mixtures of polymer and titanium isopropoxide, a precursor for TiO2, via hydrolysis in air overnight. The photoluminescence at 380-800 nm of the blend film of PT-TPP20 （5 mg/mL）：Ti（OC3H7）4 （80 μL/mL） （20% volume fraction） was significantly quenched in the 50% Ti（OC3H7）4 blend film, indicating that rapid and efficient separation of photoinduced electron-hole pairs.展开更多
The density functional theory was employed to study the structures, ionization potentials（IPs）, electron affinities（EAs）, and HOMO-LUMO gaps（ΔH-L） of the oligomers. The time-dependent density functional theory...The density functional theory was employed to study the structures, ionization potentials（IPs）, electron affinities（EAs）, and HOMO-LUMO gaps（ΔH-L） of the oligomers. The time-dependent density functional theory（TD-DFT） and ZINDO were employed to study the lowest excitation energies（Egs） and the absorption and emission spectra of the oligomers of polyfluorene（PF） and poly（fluorene-co-thiophene）（PFT）. By extrapolating ΔH-L and Egs to those of infinite chain length, band gaps and effective conjugation lengths of the corresponding polymers were obtained. The IPs, EAs and 2abs of the polymers were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero（I/n=0）. The outcome shows the decreased dihedral angle between fluorene and thiophene units in the PFT compared to that between fluorene units in the PF results in the increased efficient conjugation of PFT. These cause both the maximal absorption and emission wavelengths of PFT red-shifted compared with those of PF.展开更多
A block copolymer consisting of polyfluorene (PF) and polytriarylamine (PTAA) functionalized with green emitting phenoxazine moiety at the junction point of two blocks was designed and prepared for electroluminescent ...A block copolymer consisting of polyfluorene (PF) and polytriarylamine (PTAA) functionalized with green emitting phenoxazine moiety at the junction point of two blocks was designed and prepared for electroluminescent application. PF homopolymer was synthesized by Suzuki coupling polymerization, and was reacted with brominated phenoxazine. In the presence of the resulting PF functionalized with phenoxazine, C-N coupling polymerization of 4-(4’-bromophenyl)-4’’-butyldiphenylamine was carried out to afford a triblock copolymer, PTAA-phenoxazine-PF-phenoxazine-PTAA (PF-Ph-PTAA). Two types of random copolymers were also synthesized with fluorene and phenoxazine (PF2) by Suzuki coupling polymerization for comparison. All the polymers were soluble in common organic solvents and readily formed thin films by a solution processing. Prepared polymers exhibited similar UV absorption and PL emission in chloroform solutions. In a film state, the existence of phenoxazine unit drastically changed PL spectra. Although the content of phenoxazine unit in PF-Ph-PTAA was relatively high (13 mol%), it showed similar PL spectrum to that of PF2(phenoxazine content, 0.2 mol%) indicating that phenoxazine unit is isolated in single polymer chain nevertheless the high content. EL device based on PF-Ph-PTAA showed green-emission, suggesting that emission sites predominantly located in the vicinity of phenoxazine moiety because of its shallow HOMO level.展开更多
The inorganic-organic hybrid junction was synthesized on ITO glass substrate, which was consisted of an n-type ZnO nanorods （NRs） grown by low-temperature aqueous chemical growth method and a p-type polyfluorene （P...The inorganic-organic hybrid junction was synthesized on ITO glass substrate, which was consisted of an n-type ZnO nanorods （NRs） grown by low-temperature aqueous chemical growth method and a p-type polyfluorene （PF） organic film fabricated by spin-coating. The experimental results indicate that densely and uniformly distributed ZnO nanorods are successfully grown on the PF layer. The thickness of the PF layer plays a dominant role for the current-voltage （I-V） characteristic of the ZnO NRs/PF inorganic-organic hybrid junction device, and a p-n junction with obviously rectifying behavior is achieved with optimal PF layer thickness. The photoluminescence （PL） spectrum covering the broad visible range was obtained from the n-ZnO nanorods/p-polyfluorene （PF） structure, which was originated from the combination of the PF-related blue emission and the ZnO-related deep level emission.展开更多
Electroluminescent characteristics were investigated for the blue emitting devices fabricated with the blend systems consisting of hole transporting polytriarylamine (PTAA), electron transporting polyfluorene (PF), an...Electroluminescent characteristics were investigated for the blue emitting devices fabricated with the blend systems consisting of hole transporting polytriarylamine (PTAA), electron transporting polyfluorene (PF), and a block copolymer with both segments (PF-b-PTAA) as an active layer in order to elucidate the relationship between the chemical nature and morphology of the active layer, and EL performance. The addition of PF-b-PTAA to PF homopolymer afforded the hole injecting and/or electron blocking ability to increase the efficiency. The addition to PF/PTAA blend keeping the chemical composition constant also improved the performance by controlling the morphology and/or the domain size in phase-separated films.展开更多
文摘To search for more wider absorption and higher charge carriers mobilities materials of polymer solar cell, a series of soluble alternating polyfluorene copolymers were synthesized by palladium-catalyzed Suzuki coupling reaction. Their structures were determined by 1H NMR, IR and UV-vis. And their UV-vis absorption spectra indicated that they had strong absorption over 600 nm spectral range and nearly cover 400-700 nm visible region. The band gaps of copolymers calculated according to cyclic voltammetry （CV） were between 1.96 and 2.03 eV. Polymer：TiO2 bulk-heterojunction films were made from mixtures of polymer and titanium isopropoxide, a precursor for TiO2, via hydrolysis in air overnight. The photoluminescence at 380-800 nm of the blend film of PT-TPP20 （5 mg/mL）：Ti（OC3H7）4 （80 μL/mL） （20% volume fraction） was significantly quenched in the 50% Ti（OC3H7）4 blend film, indicating that rapid and efficient separation of photoinduced electron-hole pairs.
基金Supported by the State Basic Research Development Program of China(No.2002CB613406)the National Natural Science Foundation of China(No.20673045)the Open Project of State Key Laboratory of Superamolecular Structure and Materials of Jilin University(No.SKLSSM200716)
文摘The density functional theory was employed to study the structures, ionization potentials（IPs）, electron affinities（EAs）, and HOMO-LUMO gaps（ΔH-L） of the oligomers. The time-dependent density functional theory（TD-DFT） and ZINDO were employed to study the lowest excitation energies（Egs） and the absorption and emission spectra of the oligomers of polyfluorene（PF） and poly（fluorene-co-thiophene）（PFT）. By extrapolating ΔH-L and Egs to those of infinite chain length, band gaps and effective conjugation lengths of the corresponding polymers were obtained. The IPs, EAs and 2abs of the polymers were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero（I/n=0）. The outcome shows the decreased dihedral angle between fluorene and thiophene units in the PFT compared to that between fluorene units in the PF results in the increased efficient conjugation of PFT. These cause both the maximal absorption and emission wavelengths of PFT red-shifted compared with those of PF.
文摘A block copolymer consisting of polyfluorene (PF) and polytriarylamine (PTAA) functionalized with green emitting phenoxazine moiety at the junction point of two blocks was designed and prepared for electroluminescent application. PF homopolymer was synthesized by Suzuki coupling polymerization, and was reacted with brominated phenoxazine. In the presence of the resulting PF functionalized with phenoxazine, C-N coupling polymerization of 4-(4’-bromophenyl)-4’’-butyldiphenylamine was carried out to afford a triblock copolymer, PTAA-phenoxazine-PF-phenoxazine-PTAA (PF-Ph-PTAA). Two types of random copolymers were also synthesized with fluorene and phenoxazine (PF2) by Suzuki coupling polymerization for comparison. All the polymers were soluble in common organic solvents and readily formed thin films by a solution processing. Prepared polymers exhibited similar UV absorption and PL emission in chloroform solutions. In a film state, the existence of phenoxazine unit drastically changed PL spectra. Although the content of phenoxazine unit in PF-Ph-PTAA was relatively high (13 mol%), it showed similar PL spectrum to that of PF2(phenoxazine content, 0.2 mol%) indicating that phenoxazine unit is isolated in single polymer chain nevertheless the high content. EL device based on PF-Ph-PTAA showed green-emission, suggesting that emission sites predominantly located in the vicinity of phenoxazine moiety because of its shallow HOMO level.
基金Funded by the National Natural Science Foundation of China (Nos.10804014,11004092,60807009)the Fundamental Research Funds for the Central Universities (No.DUT10LK01)
文摘The inorganic-organic hybrid junction was synthesized on ITO glass substrate, which was consisted of an n-type ZnO nanorods （NRs） grown by low-temperature aqueous chemical growth method and a p-type polyfluorene （PF） organic film fabricated by spin-coating. The experimental results indicate that densely and uniformly distributed ZnO nanorods are successfully grown on the PF layer. The thickness of the PF layer plays a dominant role for the current-voltage （I-V） characteristic of the ZnO NRs/PF inorganic-organic hybrid junction device, and a p-n junction with obviously rectifying behavior is achieved with optimal PF layer thickness. The photoluminescence （PL） spectrum covering the broad visible range was obtained from the n-ZnO nanorods/p-polyfluorene （PF） structure, which was originated from the combination of the PF-related blue emission and the ZnO-related deep level emission.
文摘Electroluminescent characteristics were investigated for the blue emitting devices fabricated with the blend systems consisting of hole transporting polytriarylamine (PTAA), electron transporting polyfluorene (PF), and a block copolymer with both segments (PF-b-PTAA) as an active layer in order to elucidate the relationship between the chemical nature and morphology of the active layer, and EL performance. The addition of PF-b-PTAA to PF homopolymer afforded the hole injecting and/or electron blocking ability to increase the efficiency. The addition to PF/PTAA blend keeping the chemical composition constant also improved the performance by controlling the morphology and/or the domain size in phase-separated films.
