H. Nagaoka, F. Ma, Dane W. deQuilettes
Feb 3, 2015
Citations
1
Influential Citations
98
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Journal
The journal of physical chemistry letters
Abstract
We investigate zirconium (Zr) incorporation into the titanium dioxide (TiO2) electron-transporting layer used in organometal halide perovskite photovoltaics. Compared to Zr-free controls, solar cells employing electrodes containing Zr exhibit increased power conversion efficiency (PCE) and decreased hysteresis. We use transient photovoltage and photocurrent extraction to measure carrier lifetimes and densities and observe longer carrier lifetimes and higher charge densities in devices on Zr-containing electrodes at microsecond times as well as longer persistent photovoltages extending from ∼milliseconds to tens of seconds. We characterize the surface stoichiometry and change in work function and reduction potential of the TiO2 upon incorporation of Zr and discuss the charge recombination at the TiO2 interface in the context of these variables. Finally, we show that the combination of Zr-TiO2 electrode modification with device pyridine treatment leads to a cumulative improvement in performance.