Enhancement of the photoluminescence of CdSe quantum dots during long-term UV-irradiation: privilege or fault in life science research?
The present study describes an impressive enhancement of the photoluminescence (PL) intensity of low-temperature synthesized CdSe nanocrystals (75 degrees C) during long-term UV-irradiation. The integrated PL-intensity of CdSe core and CdSe/ZnS core/shell nanocrystals, dispersed in chloroform, enhanced about 3 and 6 times, respectively, during 9 h exposure to UV-light, without any significant changes in the characteristic absorbance spectra and shifting of PL-spectra. After termination of the irradiation a comparatively slow photobleaching was detected with tau(1/2) = 6 h for CdSe core and tau(1/2) = 14 h for CdSe/ZnS core/shell nanocrystals. The most impressive was the effect of UV-irradiation on the photoluminescence of water-soluble CdSe nanocrystals. The integrated PL-intensity enhanced about 10 times during 11 h exposure to UV-light and the improved PL-intensity was preserved during 3 days after termination of the irradiation without any significant photobleaching. The results are discussed in the context of application of CdSe nanocrystals as novel fluorophores in life science experiments.
Zhelev
Zhivko
Z
Natural-Substance Composed Materials Group, National Institute for Advanced Industrial Science and Technology, AIST-Kyushu, Tosu, Saga-ken, Japan.
Jose
Rajan
R
Nagase
Toshimi
T
Ohba
Hideki
H
Bakalova
Rumiana
R
Ishikawa
Mitsuru
M
Baba
Yoshinobu
Y
D001690:Biological Science Disciplines; D019187:Cadmium Compounds / Q000737:chemistry / Q000528:radiation effects*; D003460:Crystallization; D049449:Luminescence; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry / Q000528:radiation effects*; D013050:Spectrometry, Fluorescence; D014466:Ultraviolet Rays
D019187:Cadmium Compounds; D018036:Selenium Compounds; C058667:cadmium selenide