| 1. |
- Hao, Yan, et al.
(författare)
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Novel Blue Organic Dye for Dye-Sensitized Solar Cells Achieving High Efficiency in Cobalt-Based Electrolytes and by Co-Sensitization
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 8:48, s. 32797-32804
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Tidskriftsartikel (refereegranskat)abstract
- Blue and green dyes as well as NIR-absorbing dyes have attracted great interest because of their excellent ability of absorbing the incident photons in the red and near-infrared range region. A novel blue D-pi-A dye (Dyenamo Blue), based on the diketopyrrolopyrrole (DPP)-core, has been designed and synthesized. Assembled with the cobalt bipyridine-based electrolytes, the device with Dyenamo Blue achieved a satisfying efficiency of 7.3% under one sun (AM1.5 G). The co-sensitization strategy was further applied on this blue organic dye together with a red D-pi-A dye (D35). The successful co-sensitization outperformed a panchromatic light absorption and improved the photocurrent density; this in addition to the open-circuit potential result in an efficiency of 8.7%. The extended absorption of the sensitization and the slower recombination reaction between the blue dye and TiO2 surface inhibited by the additional red sensitizer could be the two main reasons for the higher performance. In conclusion, from the results, the highly efficient cobalt-based DSSCs could be achieved with the co-sensitization between red and blue D-pi-A organic dyes with a proper design, which showed us the possibility of applying this strategy for future high-performance solar cells.
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| 2. |
- Koh, Teck Ming, et al.
(författare)
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Influence of 4-tert-Butylpyridine in DSCs with Co-II/III Redox Mediator
- 2013
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 117:30, s. 15515-15522
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Tidskriftsartikel (refereegranskat)abstract
- The effect of TBP on Co(II/III) redox electrolyte was examined. Photocurrent of the device can be limited in electrolyte with high TBP concentration due to its viscous nature. The higher amount of TBP in electrolyte increases the viscosity of electrolyte and consequently slows down the diffusion of Co-III species. This is a unique observation for Co(II/III) electrolyte which is not observed in I-/I-3(-) electrolyte. An increase in TBP concentration from 0.1 to 0.5 M in a cobalt electrolyte containing 0.1 M Co(bpy)(3)(TFSI)(2) and 0.033 M Co(bpy)(3)(TFSI)(3) produced a 90 mV improvement in open-circuit potential (V-oc). Using electrochemical impedance spectroscopy (EIS), this enhancement could be attributed to the reduced interfacial recombination (33%) as well as a negative shift in the conduction 0 band level of TiO2 (67%). Although the influence of TBP in iodide/triiodide and cobalt-complex electrolytes is similar, the increase of viscosity at relatively high concentration of TBP in Co electrolyte should be taken into consideration in order to accomplish high efficiency DSCs based on Co-complex electrolytes.
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| 3. |
- Koh, Teck Ming, et al.
(författare)
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Photovoltage enhancement from cyanobiphenyl liquid crystals and 4-tert-butylpyridine in Co(II/III) mediated dye-sensitized solar cells
- 2013
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 49:80, s. 9101-9103
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Tidskriftsartikel (refereegranskat)abstract
- Two cyanobiphenyl liquid crystals (LCs), 5CB (4-cyano-4'-pentylbiphenyl) and 8CB (4-cyano-4'-octylbiphenyl), are introduced as additives into Co(II/ III) electrolytes for dye-sensitized solar cells (DSCs). An electrolyte containing a combination of these LCs and 4-tert-butylpyridine (TBP) exhibits higher photovoltage than one with only TBP, resulting in higher power conversion efficiency.
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| 4. |
- Kuzmych, Oleksandr, et al.
(författare)
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Defect minimization and morphology optimization in TiO2 nanotube thin films, grown on transparent conducting substrate, for dye synthesized solar cell application
- 2012
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 522, s. 71-78
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Tidskriftsartikel (refereegranskat)abstract
- TiO2 nanotube (TNT) arrays have proven to be a perspective material for dye-or semiconductor sensitized solar cells. Although their preparation by anodic oxidation method is well elaborated for Ti foil substrate, the synthesis of high quality, homogeneous TNT arrays on a transparent conductive oxide (TCO) is still associated with some experimental challenges. In this paper we present a way of preparation of defect-free, homogenous TNT film on a TCO substrate by a combination of high temperature Ti sputtering and controlled "interrupted" anodization in viscous electrolyte. High temperature of the substrate during Ti sputter coating was found crucial for good adhesion between the Ti thin film and TCO, which seems to be the most important condition for synthesis of TNTs from a Ti thin film. The reason of poor adhesion of the Ti layer sputtered at room temperature is discussed in terms of internal stress forces. An Ar-ion sputtering was proposed as a method for removal of the non-organized top porous layer to reveal a well organized tubular geometry of TNTs and control their final lengths. Such control of morphology of the top layer is important for preparation of solid state solar cells.
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| 5. |
- Kuzmych, Oleksandr, et al.
(författare)
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Infiltration of Spiro-MeOTAD hole transporting material into nanotubular TiO2 electrode for solid-state dye-sensitized solar cells
- 2014
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5107 .- 1873-4944. ; 187, s. 67-74
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Tidskriftsartikel (refereegranskat)abstract
- TiO2 nanotubes grown by anodic oxidation of Ti thin film deposited on conducting transparent fluoride-doped tin oxide (FTO) substrate were used as a unique geometrically organized template to study the infiltration of Spiro-MeOTAD hole transporting material (HTM) inside straight pores. The TiO2 nanotube (TNT) array electrode was compared with a mesoporous one in terms of loading with an organic dye of high extinction coefficient. It was shown that it is possible to build a working solid state dye sensitized solar cell device with such a combination of materials and its performance was compared with a device in which the solid state HTM was replaced by a liquid state electrolyte.
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| 6. |
- Marinado, Tannia, et al.
(författare)
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How the Nature of Triphenylamine-Polyene Dyes in Dye-Sensitized Solar Cells Affects the Open-Circuit Voltage and Electron Lifetimes
- 2010
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 26:4, s. 2592-2598
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Tidskriftsartikel (refereegranskat)abstract
- Three donor-linker-acceptor triphenylamine-based cyanoacrylic acid organic dyes used For dye-sensitized solar cells (DSCs) have been examined with respect to their effect on the open-circuit voltage (V-oc). Our previous study showed a decrease in V-oc for DSCs based oil dyes with increased molecular size (increased linker conjugation). In the present study, we investigate the origin of V-oc with respect to (i) conduction band (E-CB) positions of TiO2 and (ii) degree of recombination between electrons in TiO2 and electrolyte acceptor species at the interface. These parameters were Studied its it function of dye structure, dye load, and I-2 concentration. Two types of behavior were identified: the smaller polyene dyes show a surface-protecting effect preventing recombination upon increased dye loading, whereas the larger dyes enhance the recombination. How the different dye structures affect the recombination is discussed in terms of dye surface blocking and intermolecular interactions between dyes and electrolyte acceptor species.
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| 7. |
- Nonomura, Kazuteru, et al.
(författare)
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Blocking the Charge Recombination with Diiodide Radicals by TiO2 Compact Layer in Dye-Sensitized Solar Cells
- 2019
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Ingår i: Journal of the Electrochemical Society. - : ELECTROCHEMICAL SOC INC. - 0013-4651 .- 1945-7111. ; 166:9, s. B3203-B3208
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Tidskriftsartikel (refereegranskat)abstract
- The addition of a compact titanium dioxide (TiO2) layer between the fluorine-doped tin oxide (FTO) coated glass substrate and the mesoporous TiO2 layer in the dye-sensitized solar cell (DSC) based on the iodide/triiodide redox couple (I-/I-3(-)) is known to improve its current-voltage characteristics. The compact layer decreases the recombination of electrons extracted through the FTO layer with I-3(-) around the maximum power point. Furthermore, the short-circuit photocurrent was improved, which previously has been attributed to the improved light transmittance and/or better contact between TiO2 and FTO. Here, we demonstrate that the compact TiO2 layer has another beneficial effect: it blocks the reaction between charge carriers in the FTO and photogenerated diiodide radical species (I-2(-center dot)). Using photomodulated voltammetry, it is demonstrated that the cathodic photocurrent found at bare FTO electrodes is blocked by the addition of a compact TiO2 layer, while the anodic photocurrent due to reaction with I-2(-center dot) is maintained.
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| 8. |
- Nonomura, Kazuteru, et al.
(författare)
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The effect of UV-irradiation (under short-circuit condition) on dye-sensitized solar cells sensitized with a Ru-complex dye functionalized with a (diphenylamino)styryl-thiophen group
- 2009
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Ingår i: International Journal of Photoenergy (Online). - : Hindawi Limited. - 1110-662X .- 1687-529X. ; :471828
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Tidskriftsartikel (refereegranskat)abstract
- A new ruthenium complex, cis-di(thiocyanato)(2,2'-bipyridine-4,4'-dicarboxylic acid)(4,4'-bis(2-(5-(2-(4-diphenylaminophenyl) ethenyl)-thiophen-2-yl)ethenyl)-2,2'-bipyridine)ruthenium(II) (named E322) has been synthesized for use in dye-sensitized solar cells (DSCs). Higher extinction coeff. and a broader absorption compared to the std. Ru-dye, N719, were aimed. DSCs were fabricated with E322, and the efficiency was 0.12% initially (4.06% for N719, as ref.). The efficiency was enhanced to 1.83% by exposing the cell under simulated sunlight contg. UV-irradn. at short-circuit condition. The reasons of this enhancement are (1) enhanceing electron injection from sensitizer to TiO2 following a shift toward pos. potentials of the conduction band of TiO2 by the adsorption of protons or cations from the sensitizer, or from the redox electrolyte and (2) improving the regeneration reaction of the oxidized dye by the redox electrolyte by the dissoln. of aggregated dye from the surface of TiO2 following the treatment.
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| 9. |
- Pettersson, Henrik, et al.
(författare)
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Trends in patent applications for dye-sensitized solar cells
- 2012
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 5:6, s. 7376-7380
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Tidskriftsartikel (refereegranskat)abstract
- Dye-sensitized solar cell (DSC) technology has grown into a massive field of research and development with a fast increasing number of scientific publications and patent applications. We have created a database for patents and patent applications that deal with dye-sensitized solar cell technology. In this paper the database has been used to analyze the number of patent applications over time, as well as technical, organizational, and geographical trends in patent applications for dye-sensitized solar cells. Activity in relation to DSC patents seriously took off after the millennium, with the majority of DSC patent applications coming from Asia. Almost 90% of the documents in the database derive from Japan, China, and Korea. From a technical perspective, approximately 75% of the DSC patent applications deal with DSC materials, mainly semiconductor materials, dyes, electrolytes, and device substrates. The DSC patent situation is complex and we recommend any potential manufacturer of DSC devices and/or DSC components to carefully analyze their freedom-to-operate.
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| 10. |
- Quintana, Maria, et al.
(författare)
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Organic chromophore-sensitized ZnO solar cells : Electrolyte-dependent dye desorption and band-edge shifts
- 2009
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Ingår i: Journal of Photochemistry and Photobiology A. - : Elsevier BV. - 1010-6030 .- 1873-2666. ; 202:2-3, s. 159-163
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Tidskriftsartikel (refereegranskat)abstract
- An organic chromophore D5 (3-(5-(4-(diphenylamino)styryl)thiophene-2-yl)-2-cyanoacrylic acid) was tested as a sensitizer in photoelectrochemical mesoporous ZnO solar cells. Using thin (similar to 3 mu m) mesoporous ZnO electrodes, high incident photon-to-current conversion efficiencies of up to 70% were obtained, while power conversion efficiencies up to 2.4% were found in simulated sunlight (100 mWcm(-2)). Long dye adsorption times (16h) could be used without aggregation or precipitation of the dye. The composition of the iodide/triiodide-based electrolyte was found to be crucial in optimization of the ZnO-based dye-sensitized solar cell. A high concentration of Li+ ions was found to be shift the ZnO conduction band edge to more negative potential, whereas opposite behavior is found for mesoporous TiO2 cells. It was also found to be detrimental for solar cell performance and stability. Electrolyte-dependent and photoinduced dye desorption from the ZnO electrode was identified as a major stability problem in D5-sensitized ZnO solar cells.
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