Enhanced resonance energy transfer from PVK to MEH-PPV in nanoparticles.

Organic semiconductor nanoparticles were prepared from poly(N-vinylcarbazole) (PVK), poly(2-methoxy-5-(2(')-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV) and their blend solution via a reprecipitation method, respectively. A wide photoluminescence band centred at 430 nm has been found in the PVK nanoparticles, which is obviously red-shifted by comparison with the PVK film. The red-shifted emission from the PVK nanoparticles has a good spectral superposition with the absorption of the MEH-PPV nanoparticles. However, the spectral superposition is very poor between the two polymers in the composite films. The markedly enhanced emission from MEH-PPV is experimentally observed in the composite polymer nanoparticles and attributed to Förster energy transfer from PVK to MEH-PPV for excitation at the absorption maximum of PVK.

Resonant electron transfer and luminescent enhancement in a toluene suspension of Si nanocrystals.

Efficient resonant electron transfer from the surface bonding structure to the conduction band of quantum confined Si nanocrystals is observed by Si nanocrystals in a toluene suspension. Based on the electron transfer mechanism, the enhancement of photoluminescence originates from the band-to-band recombination in the p-type Si nanocrystals suspended in a toluene solution. The energy levels of the electrons in the Si nanocrystals chemisorbed with toluene molecules are calculated using the method of linear combination of atomic orbitals, and the characteristics of the obtained density of states is in good agreement with the observed photoluminescence properties.