Energy transfer in poly(vinyl alcohol)-encapsulated Mn-doped ZnS quantum dots

Poly(vinyl alcohol) (PVA)-encapsulated Mn2+-doped ZnS quantum dots (PVA-ZnS:Mn2+ QDs) synthesized at 80 °C in air. The structural property was investigated using X-ray powder diffraction (XRD). The XRD analysis shows that the ZnS:Mn2+ QDs possessed a zinc blende structure and the complexes of ZnS:Mn2+ QDs with PVA molecules have been formed. The photoexcitation energy transfer is found and investigated between PVA molecules and ZnS:Mn2+ QDs using characterization techniques such as Fourier transform infrared spectroscopy (FTIR), UV-vis absorption spectroscopy, photoluminescence excitation (PLE) and photoluminescence (PL) spectroscopy. The studied results show the photoluminescence enhancement of the Mn2+ 4T1(G) - 6A1(S) emission intensity is due to the efficient energy transfer process from the ZnS host lattice and PVA capping molecules to Mn2+ centers. Moreover, Förster resonance energy transfer (FRET) efficiency from PVA molecules to the Mn2+ center within PVA-ZnS:Mn2+ QDs is about 20.28%.