Photostability enhancement of InP/ZnSe/ZnSeS/ZnS quantum dots by plasmonic nanostructures.

The effect of gold and silver plasmonic films on the photoluminescence and photostability of InP/ZnSe/ZnSeS/ZnS nanocrystals (quantum dots) is reported. Colloidal gold films promote the photostability enhancement of InP/ZnSe/ZnSeS/ZnS quantum dots (more durable emission properties in the presence of metal nanostructures) through reducing exciton lifetime. In contrast, silver decreases the photostability of InP/ZnSe/ZnSeS/ZnS quantum dots without changing the photoluminescence intensity and kinetics. By adjusting the excitation wavelength closer to the extinction band of gold nanoparticles a 1.8-fold enhancement of luminescence intensity has been obtained using a polyelectrolyte spacer between the metal and InP/ZnSe/ZnSeS/ZnS nanoparticles. Thus, plasmonics offers essential practical improvement of light emitters in terms of their durable luminescent properties upon prolonged optical excitation without losses in luminescence efficiency or even along with increased efficiency.