The enhanced random lasing from dye-doped polymer films with different-sized silver nanoparticles

We reported on the enhanced random lasing from organic dyes doped with silver nanoparticles (Ag NPs), the sizes of Ag NPs ranged from 8 nm to 250 nm. The effects of different sizes of Ag NPs on the lasing properties were studied. We found a strong dependence of the random lasing properties on the size of the Ag NPs, and the lowest threshold was achieved by the introduction of Ag NPs with the diameter of 150 nm. By studying the enhanced localized electromagnetic (EM) field due to localized surface-plasmon resonance and the scattering effect of Ag NPs in experiment and Mie theory, we found that the enhanced localized EM field plays a major role on enhanced lasing of organic dyes for the small Ag NPs (diameter < 50 nm); and the scattering effect is the dominant underlying mechanism for random lasing for the large Ag NPs (diameter >= 100 nm), which also suggest that the lowest threshold and strongest lasing are dominated by the photon scattering. (C) 2015 Elsevier B.V. All rights reserved.