Hot spots enriched plasmonic nanostructure-induced random lasing of quantum dots thin film**Project supported by the National Key Research and Development Program of China (Grant No. 2017YFA0205800), the National Natural Science Foundation of China (Grant Nos. 11734005, 61307066, and 61450110442), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20130630), the Doctoral Fund of Ministry of Education of China (Grant

Abstract

Here, a plasmon-enhanced random laser was achieved by incorporating gold nanostars (NS) into disordered polymer and CdSe/ZnS quantum dots (QDs) gain medium films, in which the surface plasmon resonance of gold NS can greatly enhance the scattering cross section and bring a large gain volume. The random distribution of gold NS in the gain medium film formed a laser-mode resonator. Under a single-pulse pumping, the scattering center of gold NS-based random laser exhibits enhanced performance of a lasing threshold of 0.8 mJ/cm2 and a full width as narrow as 6 nm at half maximum. By utilizing the local enhancement characteristic of the electric field at the sharp apexes of the gold NS, the emission intensity of the random laser was increased. In addition, the gold NS showed higher thermal stability than the silver nanoparticles, withstanding high temperature heating up to 200 °C. The results of metal nanostructures with enriched hot spots and excellent temperature stability have tremendous potential applications in the fields of biological identification, medical diagnostics, lighting, and display devices.