Eco-friendly
nano- and microtechnology

The performance of nanophotonic devices based on resonant silicon nanoparticles (Si NPs) is critically limited by their polydispersity, introduced inherently by scalable synthesis methods such as pulsed laser ablation in liquid. To overcome this, we propose a spiral inertial microfluidic device for continuous and tunable size fractionation of laser-ablated Si NPs. The device’s separation mechanism, governed by the interplay between the inertial lift and Dean drag forces, is first optimized using mixtures of polystyrene particles and is validated through numerical simulations and analytical calculations. By applying this strategy to polydisperse Si NPs (50 nm to 1 μm), we demonstrate precise size-based sorting in a simple passive microfluidic chip by systematically varying the flow rate. High flow rates (50–60 μL/min) selectively isolate larger particles in the 745–780 nm range, whereas low flow rates (30–40 μL/min) separate smaller particles of 230–260 nm, achieving a separation resolution of R = 0.78. This work establishes a robust and scalable “lab-on-a-chip” platform that surpasses conventional batch-based techniques, enabling the production of monodisperse, high-purity Si NPs essential for advanced photonic applications, e.g., the development of high-Q metasurfaces, optical biosensors and functional elements of nanophotonic chips.

Microfluidic separation, based on sedimentation in curved channels under the action of centrifugal forces, is a powerful method for sorting nanoparticles. However, most studies demonstrate performance on model monodisperse polystyrene spheres. In this work, we implement a centrifugal microfluidic chip for a centrifuge, the parameters of which are calculated based on an existing theoretical model, to solve the practical problem of separating colloidal solutions of silicon nanoparticles (Si NPs) containing Mie-resonant Si NPs synthesized by laser ablation in liquid. We demonstrate efficient separation of the ablated colloidal solution of Si NPs (size range from 50 nm to 450 μm), leading to a significant narrowing of the nanoparticle size distribution in the outlet fractions. A key result is the successful separation of Si NPs possessing strong Mie-resonances in the visible spectrum, corresponding to diameters of approximately 120–240 nm. Thus, the presented approach demonstrates the potential of centrifugal microfluidics as an effective method for separation of polydisperse nanomaterials, in particular, Si NPs with resonant optical properties.

Lanthanide-based metal-organic frameworks (Ln-MOFs) provide a structurally precise platform for upconversion luminescence engineering, yet practical applications are limited by insufficient structural stability, restricted color tunability, and the lack of excitation in the NIR-III window. Here, we report a MOF incorporating mixed-lanthanide Yb3+, Tb3+, and Eu3+ ions that addresses these challenges. The optically transparent and periodic framework enforces a uniform spatial distribution of lanthanide centers and establishes stepwise interionic energy transfer pathways, while ether-containing organic linkers enhance photo and thermal stability. Under NIR-I (980 nm) excitation, the Ln-MOFs exhibit tunable multicolor upconversion emission with high hydrolytic stability and biocompatibility, enabling reliable in vivo imaging in zebrafish models. Remarkably, under NIR-III (1960 nm) excitation, a four-photon upconversion process is observed for the first time in Ln-MOFs. Together, these results expand the excitation landscape of Ln-MOFs from NIR-I to NIR-III and confirm the potential of structurally programmable Ln-MOFs for bioimaging and nonlinear photonic applications.

We report two-dimensional (2D) metal–organic framework nanosheets (MONs) integrated with optical fiber (OF) that enable tunable light emission and biocompatible microendoscopy. Luminescent 2D frameworks based on Eu3+, Tb3+, and Y3+ ions are employed to produce freestanding MONs via freeze–thaw exfoliation, followed by integration onto the OF through solution dripping. The resulting MONs exhibit large aspect ratios of up to 2300:1 and display red, green, and blue photoluminescence (PL), respectively. Their integration with OFs enables PL color mixing, yielding tunable emission ranging from yellow to quasi-white. The MON-integrated OFs are subsequently used for light emission and in vivo microendoscopy of Casper fish, paving the way for efficient and sustainable 2D materials in optical and biomedical technologies.

The study of femtosecond laser direct writing of gold thin films is of great significance in the fields of nanophotonics, micro- and nanofabrication and functional surface preparation. In this paper, the non-equilibrium kinetic mechanism and microstructure evolution law of the interaction between femtosecond laser and gold thin films are systematically revealed by combining the multi-scale simulation of two-temperature model (TTM) and molecular dynamics (MD). In this study, the time and temperature response of the electron heat capacity to an external heat source based on the density of states function and the Sommerfeld approximation, and the influence of femtosecond laser energy on the photomechanical deformation of the gold film during the laser ablation process are analyzed by theoretical simulation research method in picosecond time scale based on the two-temperature model and coupled molecular dynamics theory (TTM-MD) in one and three dimensions, respectively. It provides a theoretical basis for the process optimization of femtosecond laser processing of metal thin films, and expands its application potential in the fields of nano sensor devices and photothermal conversion.

Abstract Halide perovskites is a recently emerged platform for the creation of efficient memristors. In turn, single-crystal inorganic perovskite would be new low-cost and flexible memory devices because of their excellent resistive switching (RS) properties, without risk of chemical and mechanical stress-generated degradation, compared with the operational instability of general thin-film perovskite memristors. Moreover, miniaturization of perovskite memristors would be useful for creating high-density memory devices. Here we demonstrate the smallest CsPbBr3 perovskite nanomemristor with volatile unipolar RS characteristics which depends on the size of a single-crystal as a resistive layer due to its overall structural stability and low sensitivity to atmosphere conditions that helps to keep the stable RS switching over 1500 times with the lowest consumption power of 70 nW. To better understand the RS mechanism, we provide a comprehensive simulation of the evolution of mixed ionic-electronic charge carriers under current-voltage (I-V) tests using a one-dimensional drift-diffusion model. Because of the nonreactive nature of the contacts, the main mechanism of resistive state switching is potential barrier modulation of the Schottky contacts through the accumulation of migrating ions at the interfaces. Our findings pave the way for ultracompact memristors as well as shed light on RS mechanism in non-filamentary perovskite-based memory devices.