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Consecutive Interfacial Transformation of Cesium Lead Halide Nanocubes to Ultrathin Nanowires with Improved Stability
摘要： Although all-inorganic CsPbX3 (X=Cl, Br, I) nanocrystals (NCs) have been considered as a promising material for photoelectronic devices, their applications are still limited because of their poor stability and the lack of in-depth understanding. Here, we demonstrate a post-treatment method for the preparation of ultrathin CsPbX3 nanowires (NWs) by treating CsPbBr3 nanocubes with thiourea solution. A systematic study showed a consecutively interfacial transformation process, in which CsPbBr3 nanocubes were first converted to Cs4PbBr6 NCs in the presence of thiourea, followed by a further transformation to CsPbBr3 NCs through an interfacial CsX-stripping process. To reduce the surface energy, an oriented attachment process has been realized and CsPbBr3 NCs aggregated to form ultrathin NWs. The ultrathin CsPbBr3 NWs exhibited high photoluminescence quantum yield (PLQY, up to 60%) and high resistance to water treatment, which can be attributed to the surface passivation by thiourea. In addition to thiourea, cysteine and thioacetamide that contain thiol group can also be used to trigger this transformation. This work can not only offer a facile method for the synthesis of efficient and stable ultrathin CsPbBr3 NWs, but also help to reveal the in-depth mechanisms which may be very useful in the field of metal halide perovskite NCs.
关键词： ultrathin nanowires,oriented attachment,Cs4PbBr6,CsPbBr3,thiourea
更新于2025-09-23 15:23:52
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On-Demand CMOS-Compatible Fabrication of Ultrathin Self-Aligned SiC Nanowire Arrays
摘要： The field of semiconductor nanowires (NWs) has become one of the most active and mature research areas. However, progress in this field has been limited, due to the difficulty in controlling the density, orientation, and placement of the individual NWs, parameters important for mass producing nanodevices. The work presented herein describes a novel nanosynthesis strategy for ultrathin self-aligned silicon carbide (SiC) NW arrays (≤ 20 nm width, 130 nm height and 200–600 nm variable periodicity), with high quality (~2 ? surface roughness, ~2.4 eV optical bandgap) and reproducibility at predetermined locations, using fabrication protocols compatible with silicon microelectronics. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopic ellipsometry, atomic force microscopy, X-ray diffractometry, and transmission electron microscopy studies show nanosynthesis of high-quality polycrystalline cubic 3C-SiC materials (average 5 nm grain size) with tailored properties. An extension of the nanofabrication process is presented for integrating technologically important erbium ions as emission centers at telecom C-band wavelengths. This integration allows for deterministic positioning of the ions and engineering of the ions’ spontaneous emission properties through the resulting NW-based photonic structures, both of which are critical to practical device fabrication for quantum information applications. This holistic approach can enable the development of new scalable SiC nanostructured materials for use in a plethora of emerging applications, such as NW-based sensing, single-photon sources, quantum LEDs, and quantum photonics.
关键词： silicon carbide,telecom wavelengths,nanofabrication,self-aligned nanowires,ultrathin nanowires,quantum photonics
更新于2025-09-10 09:29:36