Solution-process perovskite quantum dots (QDs) are promising materials to be utilized in photovoltaics and photonics with their superior optical properties. Advancements in top-down nanofabrication for perovskite are thus important for practical photonic and plasmonic devices. However, different from the chemically synthesized nano/micro-structures that show high quality and low surface roughness, the perovskite QD thin film prepared by spin-coating or the drop-casting process shows a large roughness and inhomogeneity. Low-roughness and low-optical loss perovskite QD thin film is highly desired for photonic and optoelectronic devices. Here, this work presents a pressure-assisted ligand engineering/recrystallization process for high-quality and well-thickness controlled CsPbBr3 QD film and demonstrates a low-threshold and single-mode plasmonic lattice laser. A recrystallization process is proposed to prepare the QD film with a low roughness (RMS = 1.3 nm) and small thickness (100 nm). Due to the low scattering loss and strong interaction between gain media and plasmonic nanoparticles, a low lasing threshold of 16.9 µJ cm-2 is achieved. It is believed that this work is not only important to the plasmonic laser field but also provides a promising and general nanofabrication method of solution-processed QDs for various photonic and plasmonic devices.
Keywords: CsPbBr 3; perovskite quantum-dot lasers; plasmonic lasers; quantum-dot thin films; recrystallization; surface lattice resonance.
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