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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.

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]

Plasmon‐enhanced electrochemiluminescence (ECL) at the single‐nanoparticle (NP) level was investigated by ECL microscopy. The Au NPs were assembled into an ordered array, providing a high‐throughput platform that can easily locate each NP in sequential characterizations. A strong dependence of ECL intensity on Au NP configurations was observed. We demonstrate for the first time that at the single‐particle level, the ECL of Ru(bpy)32+‐TPrA was majorly quenched by small Au NPs (<40 nm), while enhanced by large Au ones (>80 nm) due to the localized surface plasmon resonance (LSPR). Notably, the ECL intensity was further increased by the coupling effect of neighboring Au NPs. Finite Difference Time Domain (FDTD) simulations conformed well with the experimental results. This plasmon enhanced ECL microscopy for arrayed single NPs provides a reliable tool for screening electrocatalytic activity at a single particle. [ABSTRACT FROM AUTHOR]

A versatile strategy to print hybrid upconversion/perovskite nanoparticle clusters based on nanoxerography has been developed. The individual hybrid cluster can be tuned by different upconversion nanoparticles (UCNPs), perovskite quantum dots (QDs), and their combinations to visualize multicolor. Based on the precise positioning of the array system, the structural and optical properties of each cluster in the array can be in situ and simultaneously characterized. This approach provides a straightforward and robust platform for high‐throughput preparation and characterization of the hybrid clusters, and the ability to position functional nanoparticles at a desired area with nanoscale accuracy exhibits great potential in fabricating advanced nanodevices. [ABSTRACT FROM AUTHOR]