Random lasers are generated by multiple light scattering in disordered optically gain medium, which are fundamentally different from conventional lasers. Control of emission properties, especially emission wavelength for random lasers is still challenging due to absence of optical cavity. Although plasmonic random lasers exhibit well‐controlled properties, most of studies on plasmonic random lasers to date are still focused on scattering amplification by disorder metal nanoparticles. Here, a tunable random laser based on emitters of Nile red/poly‐methyl methacrylate (PMMA) coupled to plasmonic resonant nanocavities of silver nanorod arrays is presented. The plasmonic random laser has very strong and narrow emission peaks and a very low lasing threshold of 22.8 µJ, resulting from plasmon resonance energy transfer (PRET), the enhanced absorption, scattering, and excitation rates of Nile red/PMMA due to strong localized electric fields in the nanocavities, and enhanced multiple light scattering from the disorder–order hybrid silver nanorod arrays. Furthermore, the lasing wavelength can be tuned in a wide range from 623 to 654 nm by different order harmonic modes of the plasmonic resonant nanocavities. This work not only provides a new strategy to design tunable random lasers, but also opens up their potential applications in medicine and sensing.

Red-emitting perovskite materials have received widespread attention as long-wavelength optical-gain media. However, the easy phase change in air limits its practical application. In this study, red CsPbBrxI3-x/SiO2 quantum dots (QDs) were prepared by a ligand-mediated hot injection method in which 3-aminopropyl-triethoxysilane (APTES) is used instead of the usual oleylamine (OAm) ligand. Through the hydrolysis of amino groups, a thin silicon layer is formed on the QD surface, improving the stability and without causing the aggregation of QDs. We find that the I/Br ratio and the QD size could be tuned by adjusting the APTES amount. Moreover, this ligand-mediated synthesis effectively passivates the surface defects, so the photoluminescence quantum yield is remarkably improved and the carrier lifetime is prolonged. The amplified spontaneous emission (ASE) is achieved under 532 nm nanosecond laser excitation. Compared with the original CsPbBrI2-OAm QD films, the threshold of CsPbBrxI3-x/SiO2 QD films is reduced from 403.5 to 98.7 μJ cm-2, and the radiation stability is significantly enhanced. Therefore, this material shows great potential in the random laser field.