Photoinduced Photoluminescence Variations of CdSe Quantum Dots in Polymer Solutions

Photoluminescence (PL) quantum efficiencies and lifetimes of CdSe quantum dots (QDs) were investigated under photoactivation in different chemical environments including polymer solutions and solvent systems. We observed considerable enhancement of the PL quantum efficiency of the QDs when photoactivated above the band gap in the presence of polymers such as poly(dimethyl siloxane) (PDMS), poly(vinyl pyrrolidone) (PVP), and poly(butadiene) (PBD). Furthermore, the PL spectra and the enhanced PL quantum efficiencies of the QDs were considerably stabilized under continuous photoactivation in the presence of dissolved polymers. Under photoactivation, the PL quantum efficiency was increased from 8% to 26−37% depending on the polymer environment. An increase of the PL quantum efficiency was also observed in solvents such as CHCl3 and n-butanol. However, photoactivation of the QDs in solvents with small dipole moments such as n-hexane and toluene resulted in substantial decreases of the PL quantum efficiency (from 8% to