Synthesis of nanocomposite materials with controlled structures and optical emissions: Application of various methacrylate polymers for CdSe quantum dots encapsulation

CdSe quantum dots (QDs) were incorporated in polymer films via in situ polymerization using one of the four different monomers having a varied hydrocarbon side chain length, namely, hexyl, lauryl, stearyl, or behenyl methacrylate. This technique resulted in the preparation of a series of the QD-based nanocomposite materials for which laser scanned confocal microscopy imaging revealed a uniform dispersion of nanoparticles within the polymethacrylate matrices. Importantly, the polymer encapsulation of highly luminescent CdSe QDs did not affect their optical properties. The films exhibit the size-quantized optical effects characteristic of QDs. The changes in photoluminescence (PL) intensity of CdSe QDs were investigated as a function of illumination duration in different chemical environments, including the above polymeric matrices and a chloroform solution. Enhancement of the photoluminescence quantum yield for photoactivated QDs in methacrylate polymers was observed. This study of quantum yields of QD-based composites is important for understanding the involvement of surface states of photoactivated QDs as well for identifying ideal polymeric hosts for photoinduced surface passivation.