Photomodulation of a Dual‐Color Luminescent System Combining Quantum Dots with a FRET Acceptor Ligand

Herein, we report on a dual‐color, photoswitchable donor‐acceptor nanosystem based on quantum dots (QD) and an anthryl quinolyl ethylene photoactive functional ligand (AQE‐FL), in which a carboxylic group is used to anchor AQE‐FL to QD. Photophysical and photochemical properties of the resulting photoswitchable QD system (psQD) were studied by steady state and time‐resolved spectroscopic methods. Efficient Förster resonance energy transfer (FRET) from QD to AQE‐FL was shown. Applicability of the Stern‐Volmer formalism (with a subdivision into static and dynamic quenching) to the psQD studied is discussed. The spectral overlap integrals of QD emission and trans‐ and cis‐AQE‐FL isomers absorption differ by 3 times that which is used for controlling the FRET efficiency. Consequently, the psQD emission is redistributed between the QD (417 nm) and AQE (520 nm) channels, i. e. dual‐color fluorescent switching between two observable states without the “off” state is recorded. Blue to green: A dual‐color, photoswitchable donor‐acceptor nanosystem based on quantum dots and an anthryl quinolyl ethylene photoactive functional ligand is reported. Photoisomerization of the ligand switches the hybrid nanosystem luminescence between the quantum dot (blue) and ligand (green) channels.