The photoluminescence (PL) characteristics of the self-assembled silica nanospheres containing coupled CdSeZnS core-shell quantum dots (QDs) on the surface of the sphere were studied. The degree of QD-coupling and the distribution of the coupled QDs were controlled by generating spatially separated QD-binding sites on the surface of the spheres and varying the QD concentration during the attachment process. When the sizes of QD spots on the surface probed by atomic force microscopy gradually increased, the band gap energy shifted to lower energy via strong Förster energy transfer between nearby QDs, and when UV-exposure time increased, the band gap energy shifted to slightly higher energy, accompanied by a large enhancement in the emission intensity. Moreover, the Bragg diffraction of the self-assembled crystal structure of the spheres affected the PL characteristics of QDs by shifting the entire emission spectra toward longer wavelength as the incident angles were increased.
Bibliographical noteFunding Information:
This work was supported by Korea Research Foundation Grant No. KRF-2000-015-DP0201, Korea. K.S.K. and H.L.J. acknowledge the support from Brain Korea 21 (BK21), and D.W.B. acknowledges the support from Yonsei University Research Fund of 1999.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)