Evidence for 鈥淪low鈥?Electron Injection in Commercially Relevant Dye-Sensitized Solar Cells by vis鈥揘IR and IR Pump鈥揚robe Spectroscopy

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• 作者：Mindaugas Juozapavicius ; Marius Kaucikas ; Stoichko D. Dimitrov ; Piers R. F. Barnes ; Jasper J. van Thor ; Brian C. O鈥橰egan
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 5, 2013
• 年：2013
• 卷：117
• 期：48
• 页码：25317-25324
• 全文大小：492K
• 年卷期：v.117,no.48(December 5, 2013)
• ISSN：1932-7455

文摘

We present femtosecond to nanosecond transient absorption (TA) data on electron injection in dye-sensitized solar cells (DSSCs) fabricated with low volatility, commercially relevant electrolytes, with and without added lithium. Results are shown over an extended time range (300 fs鈥?.3 ns) and extended wavelength range (800鈥?400 nm) for both N719 and C106 dyes. Kinetics were measured on both TiO₂ and noninjecting ZrO₂. Using the latter, we have determined the spectra and absorption coefficient of N719* across the wavelength range. We find an isosbestic point in the TA spectra on TiO₂ near 900 nm for all cells, existing from <1 ps to >1 ns. We show how measurements near this isosbestic point can give a false impression of uniformly femtosecond injection dynamics in DSSCs. Comparison of dynamics measured at 1200 nm with mid-IR transient absorption measured at 5100 nm confirms a majority proportion of slow (>10 ps) electron injection in these commercially relevant cells. We also comment on a recent publication which appears to directly contradict the results we present.