Polymer nanospheres containing CdSe/ZnS quantum dots and photochromic diaryletenes with photoswitchable luminescence

Abstract

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.