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Fast, low-cost, reliable, and multi-component nanopatterning techniques for functional colloidal nanoparticles have been dreamed about by scientists and engineers for decades. Although countless efforts have been made, it is still a daunting challenge to organize different nanocomponents into a predefined structure with nanometer precision over the millimeter and even larger scale. To meet the challenge, we report a nanoprinting technique that can print various functional colloidal nanoparticles into arbitrarily defined patterns with a 200 nm (or smaller) pitch (>125,000 DPI), 30 nm (or larger) pixel size/linewidth, 10 nm position accuracy and 50 nm overlay precision. The nanopatterning technique combines dielectrophoretic enrichment and deep surface-energy modulation and therefore features high efficiency and robustness. It can form nanostructures over the millimeter-scale by simply spinning, brushing or dip coating colloidal nanoink onto a substrate with minimum error (error ratio < 2 × 10-6). This technique provides a powerful yet simple construction tool for large-scale positioning and integration of multiple functional nanoparticles toward next-generation optoelectronic and biomedical devices.

Magnetic fields are uniquely valuable for creating colloidal nanostructured materials, not only providing a means for controlled synthesis but also guiding their self‐assembly into distinct superstructures. In this study, a magnetothermal process for synthesizing hybrid nanostructures comprising ferrimagnetic magnetite nanorods coated with fluorescent perovskite nanocrystals is reported and their magnetic assembly into superstructures capable of emitting linear and circularly polarized light are demonstrated. Under UV excitation, the superstructures assembled in a liner magnetic field produce linear polarized luminescence, and those assembled in a chiral magnetic field exhibit strong circularly polarized luminescence (CPL) with a glum value up to 0.44 (±0.004). The CPL is believed to originate from the dipolar interaction between neighboring perovskite nanocrystals attached to the chiral assemblies and the chiral‐selective absorption of the perovskite emission by the magnetite phase. The magnetic synthesis and assembly approaches and the resulting distinctive chiral superstructures are anticipated to open up new avenues for designing diverse functional chiroptical devices. [ABSTRACT FROM AUTHOR]

Metal–halide perovskite nanocrystals (NCs) have gained significant attention in the field of optoelectronic and photonic devices due to their promising applications. Despite their exceptional optical properties, the impact of different synthetic strategies on the fundamental nature of NCs, such as nonradiative recombination centers, remains poorly understood. In this study, we investigated the photophysical properties of CsPbBr3 NCs synthesized using two distinct methods, hot injection and ligand-assisted reprecipitation, at the individual particle level. We observed different blinking behaviors under specific photoexcitation power densities and proposed, through intensity–lifetime analysis and Monte–Carlo simulations, that these different synthetic strategies can fabricate NCs with similar crystal structures but distinct surface quenchers with varying energy levels, which significantly affected the photo-induced blinking-down and blinking-up behaviors in individual NCs. Our findings indicate a practical and feasible approach for controlling defect engineering in perovskite NCs, with significant implications for their use in optoelectronic and other technological applications. [ABSTRACT FROM AUTHOR]

All-inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) have attracted significant attention as promising photoelectric materials in recent years. Their non-fluorescent derivative, Cs4PbX6, can be transformed into highly fluorescent CsPbX3 through a CsX extraction process under appropriate aqueous conditions. This highly responsive turn-on fluorescence holds great promise in humidity sensing applications. Here, we assembled Cs4PbBr6 NCs into a nanoarray using a nanoxerography technique and investigated their application in micro-region humidity sensing. Due to the nanoscale reaction unit of each spot, the Cs4PbBr6 nanoarray exhibited high sensitivity towards trace water molecules. The detection range of 10–86% and the limit of detection (LOD) of 9.5% were obtained. In addition, the fluorescence could rapidly respond within 1 minute upon exposure to humid gas and achieve stability in less than 6 minutes, thereby significantly improving response speed compared to previous reports. Furthermore, the array pattern ensured statistical data acquisition, enhancing detection reliability. [ABSTRACT FROM AUTHOR]