A Few-Minute Synthesis of CsPbBr₃ Nanolasers with a High Quality Factor by Spraying at Ambient Conditions

Abstract

Inorganic cesium lead halide perovskite nanowires, generating laser emission in the broad spectral range at room temperature and low threshold, have become powerful tools for the cutting-edge applications in the optoelectronics and nanophotonics. However, to achieve high-quality nanowires with the outstanding optical properties, it was necessary to employ long-lasting and costly methods of their synthesis, as well as postsynthetic separation and transfer procedures that are not convenient for large-scale production. Here we report a novel approach to fabricate high-quality CsPbBr3 nanolasers obtained by rapid precipitation from dimethyl sulfoxide solution sprayed onto hydrophobic substrates at ambient conditions. The synthesis technique allows producing the well-separated nanowires with a broad size distribution of 2–50 μm in 5–7 min, being the fastest method to the best of our knowledge. The formation of nanowires occurs via ligand-assisted reprecipitation triggered by intermolecular proton transfer from (CH3)2­CHOH to H2O in the presence of a minor amount of water. The XRD patterns confirm an orthorhombic crystal structure of the as-grown CsPbBr3 single nanowires. Scanning electron microscopy images reveal their regular shape and truncated pyramidal end facets, while high-resolution transmission electron microscopy ones demonstrate their single-crystal structure. The lifetime of excitonic emission of the nanowires is found to be 7 ns, when the samples are excited with energy below the lasing threshold, manifesting the low concentration of defect states. The measured nanolasers of different lengths exhibit pronounced stimulated emission above 13 μJ cm–2 excitation threshold with quality factor Q = 1017–6166. Their high performance is assumed to be related to their monocrystalline structure, low concentration of defect states, and improved end facet reflectivity.

Amplified Spontaneous Emission and Random Lasing in MAPbBr3 Halide Perovskite Single Crystals

“…In most of the works, the main conclusion about the lasing nature of the emission is made based on the narrow line width and threshold behavior [ 2–5,7–16,18,19,21,22,25–27,30,32–43 ] of the emission. Rarely, the emission polarization was tested, [ 11,13,23,24,27,28,32–37,39 ] the direct observation of the light field distribution in the resonator was made, [ 10,13,14,16,18,19,21,34,39,41 ] or the laser emission directionality was observed. [ 22,27,31,34,36 ] To the best of our knowledge, the intensity correlation measurements above the lasing threshold was demonstrated only in ref.…”

Synthesis of Highly Photoluminescent All-Inorganic CsPbX3 Nanocrystals via Interfacial Anion Exchange Reactions

“…For the samples were synthesized by Cs 4 PbBr 6 transformation with KI aqueous solution, the average width and length were 22 nm and 50 nm, respectively, and the high-aspect-ratio was 2.27. According to previous studies, this phenomenon is believed to be due to the self-assembly phenomenon of water on the formation of perovskite crystals [26,27,28]. This provides a new opportunity to directly synthesize crystals with different morphologies of other components.…”

Perovskite nanowire lasers on low-refractive-index conductive substrate for high-Q and low-threshold operation

“…A droplet containing PbBr 2 and CsBr mixed in 1:1 stoichiometric ratio in anhydrous dimethyl sulfoxide (DMSO) is deposited on hydrophobic substrate and exposed to 2-propanol-water (IPA•H 2 O) azeotropic vapor for a short time at 50°C (Figure 1a; for details, see Section 4). The mechanism of NWs formation is described in our previous report [29]. It was established that ionic species (it could be…”

“…Dynamic absorption and release of the ionic ligands by the seed crystals occurring in the presence of perovskite precursors enables the in situ crystallization process. As a result, separate monocrystalline NWs adopting an orthorhombic structure are formed on the substrate [29].…”

“…substrates (Table 1) [29,[35][36][37]. We assume that such remarkable improvement of Q las could stem from decent optical contrast between the NW (n = 2.3) and substrate (n eff = 1.15) preventing the leakage loss.…”