We prepared for the first time photoactive colloidal nanospheres consisting of hydrophobic CdSe/ZnS core−shell quantum dots encapsulated in an amphiphilic PMAT polymeric shell containing photochromic diarylethene DAE1 with stoichiometry of ∼6 dye molecules per single quantum dot. The UV-induced photoisomerization of DAE1 molecules results in the partial quenching of the quantum dot emission due to FRET from the quantum dot to DAE1 photoisomer with its absorption band spectrally overlapped with the quantum dot emission. The modulation of the quantum dot emission is reversible under cyclic UV−vis-induced open−closed photoisomerization of DAE1.

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A spectral study of photochromic CdSe quantum wells containing chromenes and diarylethene was carried out.

The results of studies of the spectral-kinetic (absorption and fluorescent) characteristics of the polymer nanospheres created by us (containing luminescent inorganic CdSe/ZnS quantum dots and photochromic diarylethene molecules) incorporated into a polymer film are presented. A reversible modulation of the fluorescence intensity of quantum dots, caused by the photoisomerization of diarylethene molecules, was found. It is shown that nanospheres in polymer matrices exhibit higher efficiencies of both photoinduced modulation of QD radiation and Forster resonance energy transfer (FRET) from QDs to the cyclic isomer of DAE as compared to solutions. The results can be used, for example, to create luminescent photocontrolled panels based on films containing fluorescent nanoparticles. Keywords: photochromism, fluorescence, quantum dot, Forster resonance energy transfer, polymer nanospheres, polymer films

A study was carried out and a comparative analysis of the spectral-kinetic (absorption and fluorescent) characteristics of nanospheres containing luminescent inorganic quantum dots (QDs) CdSe/ZnS, covered with an amphiphilic polymer shell, which ensures the stability of nanospheres in aqueous colloidal solutions and the possibility of introducing into them hydrophobic photochromic diarylethene molecules with different structure. Photoinduced reversible isomerization of diarylethene molecules causes modulation of the photoluminescence signal of quantum dots, including through the control of the efficiency of resonant energy transfer (FRET) from quantum dots to the cyclic isomer of diarylethene. The FRET efficiency turned out to be the highest in nanospheres with DAE2 and DAE4. The value of the quality index (QF) of the FRET photomodulator (which shows the efficiency of modulation of the quantum yield of QD photoluminescence), introduced in this work, varies for samples with different diarylethenes from 0.003 (for DAE1) to 0.09 (for DAE2). Nanospheres containing luminescent nanoparticles of various shapes can be used in the development of luminescent photocontrolled panels, fluorescent markers, etc. Keywords: quantum dots, fluorescence, Forster resonance energy transfer, nanocomposites, photochromism, diarylethenes.