Porphyrin-Sensitized Solar Cells with Cobalt (II/III)-Based Redox Electrolyte Exceed 12 Percent Efficiency

Laboratory for Photonics and Interfaces, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, Lausanne-1015, Switzerland.
Science (Impact Factor: 33.61). 11/2011; 334(6056):629-34. DOI: 10.1126/science.1209688
Source: PubMed


The iodide/triiodide redox shuttle has limited the efficiencies accessible in dye-sensitized solar cells. Here, we report
mesoscopic solar cells that incorporate a Co(II/III)tris(bipyridyl)–based redox electrolyte in conjunction with a custom synthesized donor-π-bridge-acceptor zinc porphyrin dye
as sensitizer (designated YD2-o-C8). The specific molecular design of YD2-o-C8 greatly retards the rate of interfacial back electron transfer from the conduction band of the nanocrystalline titanium dioxide
film to the oxidized cobalt mediator, which enables attainment of strikingly high photovoltages approaching 1 volt. Because
the YD2-o-C8 porphyrin harvests sunlight across the visible spectrum, large photocurrents are generated. Cosensitization of YD2-o-C8 with another organic dye further enhances the performance of the device, leading to a measured power conversion efficiency
of 12.3% under simulated air mass 1.5 global sunlight.

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Available from: Aravind Kumar Chandiran, Dec 25, 2014
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    • "The I À /I 3 À redox couple is generally used, in DSSCs electrolytes, despite the problems related to the long-term stability (Lee et al., 2010; Yanagida et al., 2009) and the partial absorption of visible light (Hamann, 2012). Iodine-free liquid electrolytes based on cobalt (II)/(III) organic complexes (shuttles) have been applied with efficiencies up to 12.3%, in DSSC sensitized with a porphyrin organic dye (Yella et al., 2011). Another interesting 0038-092X/Ó 2015 Elsevier Ltd. "
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    Solar Energy 12/2015; 122:87-96. DOI:10.1016/j.solener.2015.08.032 · 3.47 Impact Factor
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    • "Pure brookite without rutile or, anatase is rather difficult to be prepare. TiO 2 was used in a wide range of electronic and optical applications such as thin film MOS capacitors[3], organic light emitting diodes [4], photochromic devices[5], optical waveguides[6], anti-reflecting coatings[7], Solar cells[8] [9] [10] [11], photo catalyst[12] [13] [14] and gas sensors [15] [16].Up to now,various techniquesare available for the preparation of the TiO 2 thin films, such aselectron-beam evaporation [17], sputtering [18] [19], pulsed laser deposition [20],hydrothermal method [12] spray pyrolysis [16], chemical vapor deposition [21] and the sol-gel spin coating [22]. Among these techniques, sol gel spin coating process has been successfully applied to synthesize a wide variety of inorganic and organic materials. "
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    • "Ho et al. developed process for ordering and macroscopic TiO2 light harvesters with 6.5% [14] [15]. However, the photoelectrochemical performance of anatase-TiO2 nanoparticles is still not optimal due to poor electron transport, aggregation tendency of TiO2 nanoparticles and high recombination rate [16]. "
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