Ligand Engineering and Recrystallization of Perovskite Quantum‐Dot Thin Film for Low‐Threshold Plasmonic Lattice Laser

Abstract

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.

Control of Lateral Assembly and Vertical Stacking in Spin-Coated Lead Halide Perovskite Nanocrystal Films for Enhanced Photoluminescence Efficiency

“…The details of the model calculation are explained in the SI (section 2.6). Furthermore, recent studies of plasmonic and photonic structures ,, and their mutual couplings with CsPbBr 3 NCs − stress the importance of our findings, whereby LHP NC assemblies are manipulatable to induce novel interactions with the external medium, for exploring future technology and applications.…”

High-Quality Solution-Processed Quasi-2D Perovskite for Low-Threshold Lasers

“…The RMS roughness of films 1, 2, 3, 4, and 5 are 2.9 1.9, 2.3, 3.4, and 4.1 nm, respectively, as summarized in Figure f. All the above characterization suggests that the morphology and microscopic structures of P2F8 film can be optimized through the engineered spin coating process, which is of significant importance for the realization of CW lasers and plasmonic lasers. , …”

“…All the above characterization suggests that the morphology and microscopic structures of P2F8 film can be optimized through the engineered spin coating process, which is of significant importance for the realization of CW lasers and plasmonic lasers. 44,45 PL spectroscopy and laser gain properties of these quasi-2D perovskite thin films are investigated using a 343 nm microscopic femtosecond laser. As shown in Figure 5a, the PL spectrum of film 2 at low pump densities (<11 μJ/cm 2 ) shows a central wavelength of 547 nm and a fwhm width of 26.75 nm corresponding to a spontaneous emission.…”

“…Smooth surfaces are of critical importance for lasing. , In the next step, the surface roughness of all films is investigated using AFM. As shown in Figure , film 2 shows the smallest surface height fluctuation among all of the samples.…”

Laser Technology for Perovskite: Fabrication and Applications

“…[57,58] Laser irradiation on a solution or film of perovskite precursors can trigger chemical reactions and generate PQDs. [59][60][61] Gao et al reported the in situ fabrication and patterning of crystallized CsPbBr 3 /CsPb 2 Br 5polymer nanocomposites using a 532 nm fs laser (Figure 3a). [62] With laser irradiation, nonlinear absorption resulted in the polymerization of the g-butyrolactone solvent with saturated perovskite precursors, which contributed to the localized growth of PNCs.…”