Photocorrosion-Assisted Transformation of Metal Selenide Nanocrystals into Crystalline Selenium Nanowires

详细信息    查看全文

• 作者：Whi Dong Kim ; F谩bio Baum ; Dahin Kim ; Kangha Lee ; Jun Hyuk Moon ; Doh C. Lee
• 刊名：Crystal Growth & Design
• 出版年：2014
• 出版时间：March 5, 2014
• 年：2014
• 卷：14
• 期：3
• 页码：1258-1263
• 全文大小：471K
• 年卷期：v.14,no.3(March 5, 2014)
• ISSN：1528-7505

文摘

We report the transformation of several metal selenide nanocrystals (NCs), including PbSe, CdSe, ZnSe, and PbSe/CdSe core/shell NCs, in dimethyl sulfoxide (DMSO) in acidic solutions at room temperature. In this study, the DMSO solution of metal selenide NCs was mixed with nitric acid, which was used to adjust the pH of the solution. Upon mixing, the metal selenide NCs readily transformed into crystalline selenium (trigonal structure) nano- or microwires under ambient light, whereas little or no transformation occurred in the dark. Photocorrosion, where the photogenerated carriers within the NCs participate in the cleavage of the metal and selenium atoms, turns out to be responsible for the transformation. DMSO removes organic ligands on the NC surface and creates surface trap sites for photoinduced charge carriers. Then, nitric acid helps shift the reduction potentials, thereby promoting a 鈥渃athodic reduction鈥? In this sense, the photocorrosion rate can be controlled by several parameters, such as the absorption cross section of the selenide NCs and the pH. The diameter and shape of the resulting selenium wires help gauge the transformation rate and thus unveil the transformation mechanism.