Hyperspectral Imaging of Exciton Photoluminescence in Individual Carbon Nanotubes Controlled by High Magnetic Fields
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- 作者：Jack A. Alexander-Webber ; Clement Faugeras ; Piotr Kossacki ; Marek Potemski ; Xu Wang ; Hee Dae Kim ; Samuel D. Stranks ; Robert A. Taylor ; Robin J. Nicholas
- 刊名：Nano Letters
- 出版年：2014
- 出版时间：September 10, 2014
- 年：2014
- 卷：14
- 期：9
- 页码：5194-5200
- 全文大小：509K
- ISSN：1530-6992
文摘
Semiconducting carbon nanotubes (CNTs) provide an exceptional platform for studying one-dimensional excitons (bound electron鈥揾ole pairs), but the role of defects and quenching centers in controlling emission remains controversial. Here we show that, by wrapping the CNT in a polymer sheath and cooling to 4.2 K, ultranarrow photoluminescence (PL) emission line widths below 80 渭eV can be seen from individual solution processed CNTs. Hyperspectral imaging of the tubes identifies local emission sites and shows that some previously dark quenching segments can be brightened by the application of high magnetic fields, and their effect on exciton transport and dynamics can be studied. Using focused high intensity laser irradiation, we introduce a single defect into an individual nanotube which reduces its quantum efficiency by the creation of a shallow bound exciton state with enhanced electron鈥揾ole exchange interaction. The emission intensity of the nanotube is then reactivated by the application of the high magnetic field.