| 1. |
- Andersson, M.R., et al.
(författare)
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The effect of the polymerisation temperature on molecular weight and photoluminescence quantum yield for a phenylsubstituted PPV
- 2001
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 119:1-3, s. 63-64
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Tidskriftsartikel (refereegranskat)abstract
- We present the synthesis and characterisation of poly(2-(2',5'-bis(2?-ethylhexyloxy)phenyl)-1, 4-phenylenevinylene) (BEHP-PPV) polymerised under different conditions. The photoluminescence efficiencies (?PL) in the solid state of BEHP-PPV obtained at 144°C and 0°C are 28% and 60%, respectively. Polymerisation temperatures below 0°C decreases the molecular weight without changing the photoluminescence efficiency to any large extent.
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| 2. |
- Inganäs, Olle, et al.
(författare)
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Recent progress in thin film organic photodiodes
- 2001
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 121:1-3, s. 1525-1528
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Tidskriftsartikel (refereegranskat)abstract
- We review current developments in organic photodiodes, with special reference to multilayer thin film optics, and modeling of organic donor-acceptor photodiodes. We indicate possibilities to enhance light absorption in devices by nanopatterning as well as by blending, and also discuss materials science issues of nanostructure in blends and in vertically stratified multilayer devices. Our current best devices have external efficiencies of 30-50% in between 400-600 nm, and show fill factors of 0.54 illuminated under weak monochromatic light.
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| 3. |
- Johansson, D.M., et al.
(författare)
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Convenient synthetic route to poly(p-phenylene-1,2-diphenylvinylenes)
- 2000
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 113:3, s. 293-297
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and characterization of two soluble poly(p-phenylenevinylene)s substituted with phenyl groups on the vinylene moiety is reported. The polymers are poly(1,4-phenylene-1,2-diphenylvinylene) (PPV-DP) and poly(1,4-phenylene-1,2-(3'-(2?-ethylhexyloxy))-diphenylvinylene) (PPV-mEHDP). The monomers containing chloromethyl groups were polymerized with excess potassium tert-butoxide in dioxane at room temperature. The polymerization conditions are optimized. The photoluminescence (PL) properties of the polymers showed an increase in the PL efficiency in film from 19% for PPV-DP to 37% for PPV-mEHDP. Both polymers emitted green light with higher intensity in film than in solution.
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| 4. |
- Johansson, D.M., et al.
(författare)
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Synthesis and characterisation of polyfluorenes with light-emitting segments
- 2001
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 121:1-3, s. 1761-1762
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Tidskriftsartikel (refereegranskat)abstract
- We present the synthesis and characterisation of two copolymers. They consists of poly(9-hexyl-9-(2'-ethylhexyl)fluorene) (HEH-PF) with a small amount of another polymer with a narrow band-gap. The synthetic route was designed to allow the incorporation of only one low band-gap segment per polymer chain. Photoluminescence measurements showed that energy transfer from the PF-segments to the low band-gap segments, did occur. In the solid state, all emissions were detected from the low band-gap segments with photoluminescence quantum yields up to 68%. One copolymer showed a low threshold for lasing (2 µJ/cm2) in a microcavity device.
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| 5. |
- Johansson, D.M., et al.
(författare)
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Synthesis and characterization of highly soluble phenyl-substituted poly(p-phenylenevinylenes)
- 2000
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 33:7, s. 2525-2529
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Tidskriftsartikel (refereegranskat)abstract
- We present the synthesis and characterization of soluble, high molecular weight phenyl-substituted poly(p-phenylenevinylenes). The studied polymers are poly(2-(2',5'-bis(2?-ethylhexyloxy)phenyl)- 1,4-phenylenevinylene) (BEHP-PPV) and copolymers of BEHP-PPV and poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). Their photoluminescence and electroluminescence have been examined as well as their stability to air and light. The polymers emitted green and yellow light. Stability measurements showed increased stability compared to some previously known substituted PPVs.
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| 6. |
- Theander, M., et al.
(författare)
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Interchain photoluminescence in substituted polyfluorenes
- 2001
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 119:1-3, s. 615-616
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Tidskriftsartikel (refereegranskat)abstract
- We have characterised the interchain emitting states of two substituted polyfluorenes with steady-state and time-resolved photoluminescence (PL). Site selective excitation of the interchain state shows that physical dimers are formed in the film. These dimers have low concentration in the films but exciton diffusion to the dimers is reducing the intrachain exciton lifetime. With asymmetrical substituents, the PL quantum yield is higher and the PL lifetime is longer due to lower concentration of dimers. Slow cooling from the melt, gives a new red shifted emission band and less intrachain emission. A discrepancy in the calculated radiative lifetimes suggest a fast formation of this new band.
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| 7. |
- Zhang, Fengling, et al.
(författare)
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Photodiodes and solar cells based on the n-type polymer poly(pyridopyrazine vinylene) as electron acceptor
- 2003
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Ingår i: Synthetic metals. - 0379-6779 .- 1879-3290. ; 138:3, s. 555-560
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Tidskriftsartikel (refereegranskat)abstract
- The photodiodes and solar cells based on the n-type polymer poly(pyridopyrazine vinylene) as electron acceptor were discussed. It was found that the external quantum efficiency of these diodes reached 7%. The analysis showed that under low-intensity monochromatic light, the open circuit voltage reached 900 mv.
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| 8. |
- Zhang, Fengling, et al.
(författare)
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Polymer solar cells based on MEH-PPV and PCBM
- 2003
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Konferensbidrag (refereegranskat)abstract
- Polymer solar cells based on poly(2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene(MEH-PPV) and fullerene derivative [6,6]phenyl-C61butyric acid methyl ester (PCBM) were fabricated by spin-coating. The improved performance has been achieved by blend polymer MEH-PPV with PCBM in a ratio of 1:4 by weight. The power conversion efficiency reached 1.3% under illumination of AM 1.5 with an incident power density of 78 mW/cm2 in blend single layer polymer solar cells.
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