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Abstract: The lifetime of electrons in the semiconductor electrode of dye-sensitized solar cells (DSSCs) is an important parameter determining the energy conversion efficiency. We propose a method to determine the electron lifetime by stepped current induced measurement of cell voltage in the dark (darkSCIM). Since this technique does not require the creation of photoinduced charges, the lifetime of devices with poorly injecting dyes, or indeed values for devices, which employ no sensitizer, can be determined. [Copyright &y& Elsevier]

A remarkable 300% efficiency enhancement driven by a matching increase in the short circuit current was observed in a mixed porphyrin dye-sensitized solar cell constructed from two dyes in a 3:1 ratio. Absorbed photon-to-current conversion efficiency measurements indicate an improved charge injection yield for both dyes in the mixture. Several possible origins for the observed performance enhancement are discussed. [ABSTRACT FROM AUTHOR]

We designed and synthesized two zinc phthalocyanine sensitizers (PcS27 and PcS28), substituted with branched or cyclic alkoxy chains, to investigate the structural effect of peripheral alkyl chains on the performance of dye-sensitized TiO2 solar cells. The bulky cyclic alkyl chains of PcS28 decreased the adsorption density of PcS28 on the TiO2 electrode, while the terminal branches of alkoxy chains of PcS27 did not influence the adsorption density in comparison to the previously published PcS20 with linear alkoxy chains. Under one sun conditions, PcS27 cells exhibited higher open-circuit voltage but a slightly lower energy conversion efficiency, 6.0% less than PcS20. These results suggest that the small alternation of alkoxy chains resulted in decreasing electron pushing ability of peripheral phenoxy units, giving lower short-circuit current. [ABSTRACT FROM AUTHOR]