Random lasing from dye-Ag nanoparticles in polymer films: Improved lasing performance by localized surface plasmon resonance

Random multimode lasers are achieved in 4(dicyanomethy-lene)−2- tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran (DCJTB) doped Polystrene (PS) thin films by introducing silver nanoparticles (Ag NPs) as scatterers. Ag NPs were prepared by polymer protection method. By optimizing the concentration of reactant of AgNO3 and the ratio of Ag NPs to DCJTB, the devices emit a resonance multimode peak at a center wavelength of 625 nm and the threshold excitation intensity is as low as 0.0031 mJ/pulse. It can be seen that the microscopic random resonance cavities can be formed by multiple scattering of Ag NPs which supply the localized surface-plasmon resonance (LSPR) coupling with the lasing emission to enhance the lasing efficiency. Our results demonstrate that Ag NPs are promising candidate as alternative sources of coherent light emission to realize low-threshold organic random lasers.