Yong Kon Kwon

Temperature-dependent brightening and darkening of photoluminescence from PbS quantum dots in glasses

The authors report that the darkening and brightening of photoluminescence from PbS quantum dots can be controlled by adjusting the temperature and excitation intensity. Intensity of the photoluminescence from PbS quantum dots increased with time (photobrightening) when temperature was below 150K. On the other hand, darkening was observed at temperatures above 150K. It was also possible to make a reversible change between photobrightening and photodarkening from the same specimen through the careful control of the temperature and excitation intensity.

Optical modulation of near-infrared photoluminescence from lead sulfide quantum dots in glasses

The authors report the modulation of photoluminescence intensity from lead sulfide quantum dots using two laser beams with different wavelengths. Photoluminescence from lead sulfide quantum dots in glasses was reversibly switched between the “bright” and “dark” states and degree of darkening to 16% of the initial intensity was realized. Changes in the photoluminescence were insensitive to temperature but strongly dependent on the power densities of the modulating laser beam. This efficient optical modulation has potential for optical switching and memory device applications.