| 1. |
- Kuang, Daibin, et al.
(författare)
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Stable dye-sensitized solar cells based on organic chromophores and ionic liquid electrolyte
- 2011
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Ingår i: Solar Energy. - : Elsevier BV. - 0038-092X .- 1471-1257. ; 85:6, s. 1189-1194
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Tidskriftsartikel (refereegranskat)abstract
- A series of polyene-diphenylaniline based organic dyes (coded as D5, D7, D9 and D11) have been reported for the application in ionic liquid electrolyte based dye-sensitized solar cells. The effects of substitution of organic dyes on the photovoltaic performance have been investigated, which show addition of methoxy groups on the triphenylamine donor group increases short-circuit current, open-circuit voltage and photovoltaic performance. A power conversion efficiency of 6.5% under AM 1.5 sunlight at 100 mW/cm(2) has been obtained with D11 dye in combination with a binary ionic liquid electrolyte, which when subjected to accelerated testing under one sun light soaking at 60 degrees C, the efficiency remained 90% of initial efficiency.
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| 2. |
- Thorsmolle, Verner K., et al.
(författare)
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Conduction Through Viscoelastic Phase in a Redox-Active Ionic Liquid at Reduced Temperatures
- 2012
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Ingår i: Advanced Materials. - : Wiley. - 1521-4095 .- 0935-9648. ; 24:6, s. 781-781
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Tidskriftsartikel (refereegranskat)abstract
- The phase diagram of the redox active ionic liquid 1-methyl-3-propylimidazolium iodide (PMII) is examined as a function of temperature and iodine concentration. Beyond a threshold concentration of 3.9 M, the formation of higher polyiodides gives rise to a viscoelastic phase upon cooling. Despite of the very high viscosity of such polyiodide-containing PMII melts a strikingly high conductivity is maintained through Grotthuss-type bond exchange and ionic conduction.
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| 3. |
- Thorsmolle, Verner K., et al.
(författare)
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Extraordinarily Efficient Conduction in a Redox-Active Ionic Liquid
- 2011
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Ingår i: ChemPhysChem. - : Wiley. - 1439-7641 .- 1439-4235. ; 12:1, s. 145-149
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Tidskriftsartikel (refereegranskat)abstract
- Iodine added to iodide-based ionic liquids leads to extraordinarily efficient charge transport, vastly exceeding that expected for such viscous systems. Using terahertz time-domain spectroscopy, in conjunction with dc conductivity, diffusivity and viscosity measurements we unravel the conductivity pathways in 1-methyl-3-propylimidazolium iodide melts. This study presents evidence of the Grotthuss mechanism as a significant contributor to the conductivity, and provides new insights into ion pairing processes as well as the formation of polyiodides. The terahertz and transport results are reunited in a model providing a quantitative description of the conduction by physical diffusion and the Grotthuss bond-exchange process. These novel results are important for the fundamental understanding of conduction in molten salts and for applications where ionic liquids are used as charge-transporting media such as in batteries and dye-sensitized solar cells.
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| 4. |
- Tress, Wolfgang, et al.
(författare)
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The role of the hole-transport layer in perovskite solar cells - reducing recombination and increasing absorption
- 2014
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Ingår i: 2014 IEEE 40TH PHOTOVOLTAIC SPECIALIST CONFERENCE (PVSC). - : IEEE. - 9781479943982 ; , s. 1563-1566
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Konferensbidrag (refereegranskat)abstract
- The role of the hole-transport layer (HTL) in CH3NH3PbI3 perovskite solar cells is investigated. It is found that it mainly serves three purposes: First, deposited prior to the gold electrode, it avoids direct contact of the metal electrode with the meso porous TiO2-perovskite layer, and therefore increases the selectivity of the contact. This reduces recombination as evident from an increased open-circuit voltage and a higher luminescence efficiency. Second, the HTL increases the internal quantum efficiency independent of applied voltage and illumination wavelength by reducing (diffusion) losses of charges. Third, due to a smoothing of the TiO2-perovskite mesoscopic layer the HTL increases the reflectivity of the gold electrode, allowing for a second path of the light through the absorber. Both effects result in an enhancement of the short-circuit current density.
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| 5. |
- Wang, Mingkui, et al.
(författare)
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Molecular-Scale Interface Engineering of Nanocrystalline Titania by Co-adsorbents for Solar Energy Conversion
- 2012
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631. ; 5:1, s. 181-187
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Tidskriftsartikel (refereegranskat)abstract
- The use of mixed self-assembled monolayers, combining hydrophobic co-adsorbents with the sensitizer, has been demonstrated to enhance the efficiency of dye-sensitized solar cells (DSCs). Herein, the influence of the anchoring groups of the co-adsorbents on the performance of the DSCs is carefully examined by selecting two model molecules: neohexyl phosphonic acid (NHOOP) and bis-(3,3-dimethyl-butyl)-phosphinic acid (DINHOP). The effect of these co-adsorbents on the photovoltaic performance (JV curves, incident photon-to-electron conversion efficiency) is investigated. Photoelectron spectroscopy and electrochemical impedance spectroscopy are performed to assess the spatial configuration of adsorbed dye and co-adsorbent molecules. The photoelectron spectroscopy studies indicate that the ligands of the ruthenium complex, containing thiophene groups, point out away from the surface of TiO2 in comparison with the NCS group.
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