Enhanced Dopant Solubility and Visible-Light Absorption in Cr鈥揘 Codoped TiO2 Nanoclusters

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• 作者：Mirco Chiodi ; Christine Parks Cheney ; Paolo Vilmercati ; Emanuele Cavaliere ; Norman Mannella ; Hanno H. Weitering ; Luca Gavioli
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：January 12, 2012
• 年：2012
• 卷：116
• 期：1
• 页码：311-318
• 全文大小：549K
• 年卷期：v.116,no.1(January 12, 2012)
• ISSN：1932-7455

文摘

A major obstacle toward employing TiO₂ as an efficient photoactive material is related to its large optical band gap, strongly limiting visible light absorption. Substitutional doping with both donors and acceptors (codoping) potentially leads to a significant band gap reduction, but the effectiveness of the codoping approach remains limited by the low solubility of dopants inside TiO₂. Here we show that nanostructured Cr and N codoped TiO₂ thin films can be obtained by supersonic cluster beam deposition (SCBD) with a high concentration of dopants and a strongly reduced band gap. Complementary spectroscopic investigations show that doping effectively occurs in substitutional lattice sites, inducing dopant levels in the gap that are remarkably delocalized. The high surface-to-volume ratio, typical of SCBD nanostructured films, likely facilitates the dopant incorporation. The present results indicate that SCBD films are highly promising photoactive nanophase materials.