Shell Thickness Dependent Photoinduced Hole Transfer in Hybrid Conjugated Polymer/Quantum Dot Nanocomposites: From Ensemble to Single Hybrid Level
详细信息 查看全文
- 作者：Zhihua Xu ; Corey R. Hine ; Mathew M. Maye ; Qingping Meng ; Mircea Cotlet
- 刊名：ACS Nano
- 出版年：2012
- 出版时间：June 26, 2012
- 年：2012
- 卷：6
- 期：6
- 页码：4984-4992
- 全文大小：552K
- 年卷期：v.6,no.6(June 26, 2012)
- ISSN：1936-086X
文摘
Photoinduced hole transfer is investigated in inorganic/organic hybrid nanocomposites of colloidal CdSe/ZnS quantum dots and a cationic conjugated polymer, poly(9,9鈥?bis(6-N,N,N-trimethylammoniumhexyl)fluorene-alt-phenylene, in solution and in solid thin film, and down to the single hybrid level and is assessed to be a dynamic quenching process. We demonstrate control of hole transfer rate in these quantum dot/conjugated polymer hybrids by using a series of core/shell quantum dots with varying shell thickness, for which a clear exponential dependency of the hole transfer rate vs shell thickness is observed, for both solution and thin-film situations. Furthermore, we observe an increase of hole-transfer rate from solution to film and correlate this with changes in quantum dot/polymer interfacial morphology affecting the hole transfer rate, namely, the donor鈥揳cceptor distance. Single particle spectroscopy experiments reveal fluctuating dynamics of hole transfer at the single conjugated polymer/quantum dot interface and an increased heterogeneity in the hole-transfer rate with the increase of the quantum dot鈥檚 shell thickness. Although hole transfer quenches the photoluminescence intensity of quantum dots, it causes little or no effect on their blinking behavior over the time scales probed here.