Tunable photoluminescence of polymer doped with PbSe quantum dots

Semiconductor nanoparticle/polymer composites potentially allow the design of photonic materials for optoelectronic devices. The optical characteristics of PbSe quantum dots placed in polymer matrices are investigated for potential applications in electrically controlled absorption modulators and integrated optical circuit components. The photoluminescence yield, shape of absorption band, and effects of size variation of PbSe quantum dots on spectral features are analyzed near the absorption edge of host polymers for the different concentrations of nanocrystals in the composite. It was found that for quantum dots of nominally the same size, there is a strong dependence of position of the absorption peaks in the spectrum depending on the concentration of quantum dots. This results in the emission in the 1500-1600 nm range being tunable with quantum dot concentration. A second emission in the 1200-1300 nm range was also observed and energy transfer from the polymer matrix to the quantum dot appears to mediate the strength of this photoluminescence.