Control of PbSe Quantum Dot Surface Chemistry and Photophysics Using an Alkylselenide Ligand
详细信息 查看全文
- 作者：Barbara K. Hughes ; Daniel A. Ruddy ; Jeffrey L. Blackburn ; Danielle K. Smith ; Matthew R. Bergren ; Arthur J. Nozik ; Justin C. Johnson ; Matthew C. Beard
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：June 26, 2012
- 年：2012
- 卷：6
- 期：6
- 页码：5498-5506
- 全文大小：491K
- 年卷期：v.6,no.6(June 26, 2012)
- ISSN：1936-086X
文摘
We have synthesized alkylselenide reagents to replace the native oleate ligand on PbSe quantum dots (QDs) in order to investigate the effect of surface modification on their stoichiometry, photophysics, and air stability. The alkylselenide reagent removes all of the oleate on the QD surface and results in Se addition; however, complete Se enrichment does not occur, achieving a 53% decrease in the amount of excess Pb for 2 nm diameter QDs and a 23% decrease for 10 nm QDs. Our analysis suggests that the Se ligand preferentially binds to the {111} faces, which are more prevalent in smaller QDs. We find that attachment of the alkylselenide ligand to the QD surface enhances oxidative resistance, likely resulting from a more stable bond between surface Pb atoms and the alkylselenide ligand compared to Pb-oleate. However, binding of the alkylselenide ligand produces a separate nonradiative relaxation route that partially quenches PL, suggesting the formation of a dark hole-trap.