Electron transport in silver-semiconductor nanocomposite films exhibiting multicolor photochromism
Electron transport in silver-semiconductor nanocomposite films exhibiting multicolor photochromism
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DOI：
10.1039/b511489f
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发表时间：
2005-01-01
影响因子：
3.3
通讯作者：
Tatsuma, T
中科院分区：
文献类型：
--
作者：
Kawahara, K;Suzuki, K;Tatsuma, T
在光催化沉积的Ag纳米粒子负载的TiO 2纳米多孔薄膜的光致变色性中，可见光诱导的电子从Ag到氧分子的转移起着至关重要的作用。在这里，我们研究了TiO 2对电子转移的影响。我们发现，不仅光催化沉积的银，而且电沉积的银和商业上可获得的银纳米粒子在纳米多孔二氧化钛薄膜表现出的光致变色。电沉积的银在纳米多孔ZnO薄膜中也表现出光致变色，而在纳米多孔氧化铟锡（ITO）和SiO2基体中则没有。光电化学测试结果表明，Ag上的光激发电子通过TiO 2和非激发态Ag转移到氧分子上。因此，n型半导体在激发电子和Ag+之间的电荷分离中起重要作用。非激发态Ag在TiO 2上也在氧还原的电荷分离和/或催化中起重要作用。用Pt取代未被激发的Ag，加速了电子从光激发的Ag到氧分子的传输和光致变色行为。
In the multicolor photochromism of TiO2 nanoporous films loaded with photocatalytically deposited Ag nanoparticles, visible light-induced electron transfer from Ag to oxygen molecules plays an essential role. Here we examined the effect of TiO2 on the electron transfer. We found that not only photocatalytically deposited Ag, but also electrodeposited Ag and commercially available Ag nanoparticles in a nanoporous TiO2 film exhibit the multicolor photochromism. The electrodeposited Ag exhibits the multicolor photochromism also in a nanoporous ZnO film, but not in nanoporouns indium-tin oxide (ITO) and SiO2 matrices. Photoelectrochemical measurements for the Ag-TiO2 nanocomposite elucidated that some of the photo-excited electrons on Ag are transferred to oxygen molecules via TiO2 and non-excited Ag. Thus, an n-type semiconductor plays an important role in the charge separation between the excited electrons and Ag+. Non-excited Ag on TiO2 also plays an important role in the charge separation and/or catalysis of oxygen reduction. Replacement of the non-excited Ag with Pt accelerated the electron transport from the photo-excited Ag to oxygen molecules and the photochromic behavior.