122nd General Meeting of the KCS

Type Symposium
Area Frontier of Materials Chemistry: Photosciences
Room No. Room 322
Time FRI 15:20-:
Code MAT2-3
Subject Light-Induced Modulation of Quantum Dot Conjugate Fluorescence
Authors Sung Jee Kim
Department of Chemistry, Pohang University of Science and Technology, Korea
Abstract Photo-switching or modulation of quantum dots (QDs) can be promising for many fields that include display, memory, and super-resolution imaging. However, such modulations have been mostly relied on photo-modulations of conjugated molecules in QD vicinity which typically require high power of high energy photons at UV. We report a visible light-induced facile modulation route for QD-dye conjugates. QD crystal violets conjugates (QD-CVs) were prepared and the crystal violet (CV) molecules on QD quenched the fluorescence efficiently. The fluorescence of QD-CVs showed a single cycle of emission burst as they go through three stages of (i) initially quenched ‘off’ to (ii) photo-activated ‘on’ as the result of chemical change of CVs induced by photo-electrons from QD and (iii) back to photo-darkened ‘off’ by radical-associated reactions. Multi-color on-demand photo-patterning was demonstrated using QD-CV solid films. QD-CVs were introduced into cells, and excitation with visible light yielded photo-modulation from ‘off’ to ‘on’ and ‘off’ by nearly ten folds. Individual photoluminescence dynamics of QD-CVs was investigated using fluorescence correlation spectroscopy and single QD emission analysis, which revealed temporally-stochastic photo-activations and photo-darkenings. Exploiting the stochastic fluorescence burst of QD-CVs, simultaneous multi-color super-resolution localizations were demonstrated.
E-mail sungjee@postech.ac.kr