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| 2. |
- Admassie, Shimelis, et al.
(författare)
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A polymer photodiode using vapour-phase polymerized PEDOT as an anode
- 2006
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Ingår i: Solar Energy Materials & Solar Cells. ; 90:2, s. 133-141
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Tidskriftsartikel (refereegranskat)abstract
- We report the photovoltaic properties of devices made using a highly conducting polymer electrode, from vapor-phase polymd. poly (3,4-ethylenedioxy) thiophene (VPP PEDOT) on glass substrate as an anode and a polyfluorene copolymer poly[2,7-(9,9-dioctyl-fluorene)-alt-5,5-(4',7'-di-2thienyl-2',1'3'-benzothiadiazole)] (APFO-3) mixed with [6,6]-phenyl-C61-butyric acid methylester (PCBM) in the ratio of 1:4 as the active layer. The device performance was compared with that of devices made with PEDOT-PSS on glass substrates. The surfaces of VPP PEDOT were imaged using at. force microscopy (AFM). [on SciFinder (R)]
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| 3. |
- Admassie, Shimelis, et al.
(författare)
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Synthesis, optical and electrochemical characterization of anthrancene and benzothiadiazole-containing polyfluorene copolymers
- 2006
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Ingår i: Bulletin of the Chemical Society of Ethiopia. - 1011-3924 .- 1726-801X. ; 20:2, s. 309-317
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Tidskriftsartikel (refereegranskat)abstract
- New solution-processable, anthrancene- and benzothiadiazole-containing polyfluorene copolymers (P1-P3) have been synthesized and characterized. The preparation and characterization of the corresponding blue light-emitting devices are also reported. Polymers P2 and P3 show high photoluminescence efficiency while polymer P2 does not show any significant light emission up to 8.0 V. The results show the need for balance of electron and hole transport in polymer light emitting diodes.
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| 4. |
- Gadisa, Abay, et al.
(författare)
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A new donor-acceptor-donor polyfluorene copolymer with balanced electron and hole mobility
- 2007
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Ingår i: Adv. Funct. Mater. FIELD Full Journal Title:Advanced Functional Materials. ; 17:18, s. 3836-3842
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Tidskriftsartikel (refereegranskat)abstract
- A new alternating polyfluorene copolymer poly[2,7-(9,9-dioctylfluoren)-alt-5,5-(5',8'-di-2-thienyl-(2',3'-bis-(3''-octyloxyphenyl)-quinoxaline))] (APFO-15), which has electron donor-acceptor-donor units in between the fluorene units, is synthesized and characterized. This polymer has a strong absorption and emission in the visible range of the solar spectrum. Its electroluminescence and photolumin escence emissions extend from about 560 to 900 nm. Moreover, solar cells with efficiencies in excess of 3.5 % have been realized from blends of APFO-15 and an electron acceptor mol., a mathanofullerene [6,6]-phenyl-C61-butyric acid Me ester (PCBM). It has also been obsd. that electron and hole transport is balanced both in the pure polymer phase and in polymer/PCBM bulk heterojunction films, which makes this material quite attractive for applications in opto-electronic devices. [on SciFinder (R)]
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| 5. |
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| 6. |
- Lindgren, Lars Johan, 1977, et al.
(författare)
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Blue light-emitting diodes based on novel polyfluorene copolymers
- 2007
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Ingår i: Journal of Luminescence. ; 122-123, s. 610-613
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Konferensbidrag (refereegranskat)abstract
- This study presents the synthesis and characterization of a series of fluorene-based conjugated copolymers, together with the prepn. and characterization of the corresponding light-emitting devices. The polymers consist of alkoxyphenyl-substituted fluorene units together with different amts. of a hole-transporting triphenylamine-substituted fluorene unit: 0%, 10%, 25% and 50%. All polymers (P0, P1, P2, and P3) show high photoluminescence efficiency (hPL) and light emission (both PL and EL) in the blue spectral region. Electrochem. studies show improved hole injection as the ratio of the triphenylamine-substituted segment is increased. The electroluminescence quantum efficiencies (EQEs) of the devices increase six times going from P0 to P1. Compared with P1, polymers P2 and P3 show lower efficiencies in devices. These findings indicate the presence of an optimal polymer compn., where balance between the charge-carrier mobilities has been reached. [on SciFinder (R)]
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| 7. |
- Mammo, Wendimagegn, 1954, et al.
(författare)
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New low band gap alternating polyfluorene copolymer-based photovoltaic cells
- 2007
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Ingår i: Sol. Energy Mater. Sol. Cells FIELD Full Journal Title:Solar Energy Materials & Solar Cells. ; 91:11, s. 1010-1018
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Tidskriftsartikel (refereegranskat)abstract
- New low band gap alternating polyfluorene copolymers were synthesized for use in plastic solar cells and their optical, electrochem., and photovoltaic characteristics were detd. These polymers incorporated fluorene units alternating with groups including electron-withdrawing (A) and electron-donating (D) groups in donor-acceptor-donor (DAD) sequence to achieve the lowering of band gaps. The HOMO-LUMO values were estd. from electrochem. studies. By varying the donor and acceptor strength and position of the solubilizing substituents, similar HOMO values were obtained. These values were also found to correlate well with the open circuit voltage (VOC) values detd. from photovoltaic data of the polymers blended with the acceptor PCBM. Despite similar HOMO values, the absorption spectra of the polymers differ significantly. This prompted the prepn. of photovoltaic devices consisting of blends of two polymers with complementary absorptions in combination with PCBM to harvest more photons in the polymer solar cells. [on SciFinder (R)]
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| 8. |
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| 9. |
- Zhang, Fengling, et al.
(författare)
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Low-bandgap alternating fluorene copolymer/methanofullerene heterojunctions in efficient near-infrared polymer solar cells
- 2006
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Ingår i: Advanced Materials (Weinheim, Germany). ; 18:16, s. 2169-2173
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Tidskriftsartikel (refereegranskat)abstract
- Efficient near-IR polymer solar cells based on the low-bandgap alternating fluorene copolymer APFO-Green 5 exhibit a photoresponse up to 800 nm. The copolymer performs well in combination with the common electron acceptor [6,6]-phenyl-C61-butyric acid Me ester (PCBM), reaching a power-conversion efficiency of 2.2% with a lower PCBM content in the active layer than previous devices based on low-bandgap polymers. [on SciFinder (R)]
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