The reversible photoluminescence enhancement of a CdSe/ZnS nanocrystal thin film
Abstract
We report that the storage and clearing of multi-digital data, that is, the photoluminescence (PL) intensity of CdSe/ZnS core/shell nanocrystal (NC) thin film, can be operated by a single excitation wavelength. First, a 7.4 µm-square area on the NC film was irradiated by strong light ranging in intensity from 2.64 to 1370 nW. Then, a 60 µm-square area including the pre-irradiated region was scanned with weak light (about 0.6 nW) to visualize the PL intensity difference between pre- and non-irradiated regions (I and I0, respectively). The normalized PL intensity, I/I0, increased with total pre-irradiation energy, until reaching saturation. The level of I/I0 at which the PL intensity becomes saturated reversibly increased with decreasing light intensity at pre-irradiation. The results imply that Auger ionization becomes dominant and suppresses the enhancement of the emission efficiency with higher irradiation intensities.
- Publication:
-
Nanotechnology
- Pub Date:
- July 2004
- DOI:
- 10.1088/0957-4484/15/7/019
- Bibcode:
- 2004Nanot..15..822U