Dual-functional ZnO nanorod aggregates as scattering layer in the photoanode for dye-sensitized solar cells
ABSTRACT A bilayered ZnO photoanode was constructed for dye-sensitized solar cells with a high conversion efficiency of 4.0%. One layer made of ZnO nanocrystallites increases dye adsorption, and the other consisting of ZnO nanorod aggregates provides a directed electron pathway for the electron transport together with a prominent aggregation-induced light scattering.
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ABSTRACT: ZnO is widely used as an n-type semiconductor in various solar cell structures; including dye-sensitized, organic, hybrid and solid-state solar cells. Here, we review advances in ZnO-based solar cell applications, looking at the influence of morphology, as well as the effect of different materials and sensitizers. ZnO morphologies play an important role in changing the surface area and charge transport properties, affecting the performance of the solar cells. External quantum efficiencies using purely ZnO as the active material has generally been below 3% with some dye-sensitized solar cells using liquid electrolytes above 5%. Sensitizers such as organic and inorganic dyes, quantum dots and hole conductors have been shown to influence cell efficiency by improving the absorption or providing improved charge transport. The combination of ZnO with other nanomaterials such as, TiO2, SiO2 and ZrO2 in core-shell structures or buffer layers creates improved electron transport by controlling recombination at interfaces and increasing stability of the device. The highest reported efficiencies to date were from combinational structures at 7.07% for ZnO nanosheets with TiO2 nanoparticulate coating and 7% for ZnO core-TiO2 shell structures.Journal of Nanoscience and Nanotechnology 11/2012; 12(11):8215-30. DOI:10.1166/jnn.2012.6680 · 1.34 Impact Factor
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ABSTRACT: Nanobean SnO2-embedded TiO2 hollow submicrospheres are presented as a scattering layer for the first time in dye-sensitized solar cells. This designed mesoporous submicrostructures allow to simultaneously promote dye adsorption, light harvesting, and electron transport, leading to 28% improvement in the conversion efficiency compared to film-based SnO2.Chemical Communications 01/2015; 51(14). DOI:10.1039/C4CC07700H · 6.72 Impact Factor
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ABSTRACT: Sub-micrometer sized rutile TiO2 nanorod microspheres with diameters of 500–700 nm and with a specific surface area of 63.7 m2 g−1 were synthesized via a salt-assisted hydrothermal method. Morphological evolution as a function of reaction time was carried out to gain insight into the formation mechanism of the nanorod microspheres. Unlike traditional bulk rutile TiO2 particles, the nanorod microspheres could provide dual-functions of adsorbing dye molecules and strong light-harvesting efficiency when they were fabricated as a scattering overlayer in dye-sensitized solar cells (DSSCs). Furthermore, the inherent nanorods would provide excellent electron percolation pathways for charge transfer as confirmed by electrochemical impedance spectroscopy. Consequentially, DSSC with the scattering overlayer exhibited a 39% increment of cell efficiency (7.32%) compared with the DSSC without one (5.28%), and the efficiency was also a little higher than the DSSC with the same thickness composed of only nanocrystallites (7.14%).CrystEngComm 01/2013; 15(8):1651-1656. DOI:10.1039/C2CE26691A · 3.86 Impact Factor