Spray Pyrolysis Deposition and Photoelectrochemical Properties of n-Type BiOI Nanoplatelet Thin Films
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- 作者：Nathan T. Hahn ; Son Hoang ; Jeffrey L. Self ; C. Buddie Mullins
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：September 25, 2012
- 年：2012
- 卷：6
- 期：9
- 页码：7712-7722
- 全文大小：651K
- 年卷期：v.6,no.9(September 25, 2012)
- ISSN：1936-086X
文摘
Bismuth oxy-iodide is a potentially interesting visible-light-active photocatalyst; yet there is little research regarding its photoelectrochemical properties. Herein we report the synthesis of BiOI nanoplatelet photoelectrodes by spray pyrolysis on fluorine-doped tin oxide substrates at various temperatures. The films exhibited n-type conductivity, most likely due to the presence of anion vacancies, and optimized films possessed incident photon conversion efficiencies of over 20% in the visible range for the oxidation of I鈥?/sup> to I3鈥?/sup> at 0.4 V vs Ag/AgCl in acetonitrile. Visible-light photons (位 > 420 nm) contributed approximately 75% of the overall photocurrent under AM1.5G illumination, illustrating their usefulness under solar light illumination. A deposition temperature of 260 掳C was found to result in the best performance due to the balance of morphology, crystallinity, impurity levels, and optical absorption, leading to photocurrents of roughly 0.9 mA/cm2 at 0.4 V vs Ag/AgCl. Although the films performed stably in acetonitrile, their performance decreased significantly upon extended exposure to water, which was apparently caused by a loss of surface iodine and subsequent formation of an insulating bismuth hydroxide layer.