"Laser-initiated site-selective formation of fluorescing silver–iron oxide nanocomposites for electron detection", Nanoscale, 2025, 17, 20935
There has been ongoing interest in the fabrication of silver–iron oxide composite nanostructures due to their effectiveness in antimicrobial, catalytic, and sensing applications. However, traditional processes involve multiple steps and harsh conditions, making them time-consuming and energy-intensive. A focused laser beam is used as an alternative tool to fabricate fluorescent silver–iron oxide composite nanostructures. The rapid thermal annealing and quenching process results in uniformly distributed particles that form site-selectively in the laser-irradiated regions. When performing without demanding conditions or additives, this process is more precise, energy-efficient, and cost-effective compared to traditional methods. The presence of silver within the composite enhances the intrinsic fluorescence of Fe3O4 by more than 10 times through surface plasmon resonance effects. This exclusive trait turns the composite into an effective micro-beta particle detector with in situ optical feedback. This work provides a glimpse into the benefits of developing alternative synthesis processes as a means to uncover new applications.
"Constructing high-ionic-conductivity solid-state electrolytes with improved interface stability by rapid laser processing", Journal of Energy Chemistry, 110, 712
All-solid-state batteries (ASSBs) with Li or Si anodes promise enhanced safety and high energy densities but face challenges with complex fabrication, stringent storage requirements, and pressure-dependent operation. Polyethylene oxide (PEO)-based composite solid electrolytes (CSEs) enable easy processing and flexible interfaces, supporting pressure-free operation and reducing costs. However, their low ionic conductivity remains a key limitation. Here, we present a rapid (~5 min) and eco-friendly laser modification strategy for post-synthesized PEO CSEs, achieving enhanced ionic conductivity while retaining the attributes of simple fabrication and compatibility with Li and Si anodes under pressure-free operation. Laser engineering reduces PEO crystallinity, introduces additional Li+ coordination sites, and improves interfacial stability through tailored solid electrolyte interphases. The laser-modified electrolyte enables LiFePO4//Li cells to retain 142.4 mAh g-1 after 800 cycles with 99.8 % Coulombic efficiency at 1 C and 60 °C. Moreover, without stack pressure, a Si anode paired with the laser-modified electrolyte delivers a high capacity of 1710.3 mAh g-1 with 56 % retention at 0.5 A g-1 after 50 cycles at 60 °C. Beyond performance enhancements, this work establishes a link between fluorescence emission and Li+ transport in CSEs. Specifically, fluorescence shifts to shorter wavelengths correspond to shorter molecular chain lengths and lower coordination bonds, supported by time-dependent density functional theory calculations. These factors give rise to improved Li+ transport. This optical probe offers a non-destructive approach for rapidly assessing electrolyte properties and enriching electrolyte design. Overall, this work demonstrates laser engineering as a practical post-synthetic strategy and highlights fluorescence as a practical indicator for advancing next-generation ASSBs.
"Enhanced battery performance by fluorescent defects engineering in hard carbon anodes", Chemical Engineering Journal, 514, 163279
The availability and accessibility of economical renewable energy remains a key driving factor towards encouraging the uptake of clean energy. By incorporating economical hard carbon (HC), recycled from waste into anodes for lithium-ion batteries (LIBs), and treating the resulting HC-anode with a focused laser beam, the functionalised HC-anode exhibits enhanced electrochemical performance with a specific capacity of 516 mAh g-1 at 0.1 A g-1. It achieves over 100% capacity retention for 700 cycles at 1 A g-1, and demonstrates super-long durability for 4000 cycles at 2 A g-1. The improvements are attributed to laser-tunable expanded interlayer spacing and fluorescing defects in the engineered HC-anode. DFT calculations further established that these fluorescent defects correspond to carbon vacancies (cyan fluorescence), and their complexes with H heteroatoms (green fluorescence). These defects lead to the improved electrochemical performance via enhancing Li+ adsorption energies. Given such correlation, fluorescence studies are proposed as an interesting mechanism for guiding the development of carbon materials for energy applications, which serves as a highly efficient tool for assessing the electrochemical performance, eliminating the need for costly battery fabrication and testing processes. The performance achieved and its correlation to the observable fluorescence will not only contribute towards the effort of making cheaper batteries with better performance, but also serves as a rapid and scalable probe for preliminary evaluation of battery performance.
"Room temperature ferromagnetic ordering from bound magnetic polarons in rare-earth-doped ultrathin MoS2", Journal of Materials Chemistry C , 13, 15873
Dilute magnetic semiconductors (DMSs) endowed with room-temperature ferromagnetic capabilities that arise from bound magnetic polarons (BMPs) have been attractive for spintronics, information storage and magneto-optical applications. In particular, the inclusion of rare-earth lanthanide ions as magnetic dopants in semiconductors presents significant potential owing to their strong free-ion magnetic moments. Herein, we evaluate the influence of various rare-earth dopants (Tb3+, Er3+, and Eu3+) magnetically coupled to vacancy carrier spins in MoS2 nanosheets. The manifested ferromagnetic magnitudes adopt a trend that differs from that of free ion moments, with 5% Tb-doped MoS2 exhibiting maximum saturation magnetization. The characteristic dependence of sample magnetization on dopant concentration and stringent annealing conditions (defect concentration) justifies the BMP model in describing the system. The rational creation of these ferromagnetic nanosheets is expected to provide value in low-temperature, solution-based processing of spintronic components into monolithic integrated electronics and multifunctional devices. These findings are also expected to contribute to a comprehensive understanding of the design of rare-earth-doped transition metal dichalcogenides (TMDs) as DMSs for such future spintronic applications.
"Programmable Interfacial Band Configuration in WS2/Bi2O2Se Heterojunctions", ACS Nano, 18, 16832
Van der Waals heterojunctions based on transition-metal dichalcogenides (TMDs) offer advanced strategies for manipulating light-emitting and light-harvesting behaviors. A crucial factor determining the light–material interaction is in the band alignment at the heterojunction interface, particularly the distinctions between type-I and type-II alignments. However, altering the band alignment from one type to another without changing the constituent materials is exceptionally difficult. Here, utilizing Bi2O2Se with a thickness-dependent band gap as a bottom layer, we present an innovative strategy for engineering interfacial band configurations in WS2/Bi2O2Se heterojunctions. In particular, we achieve tuning of the band alignment from type-I (Bi2O2Se straddling WS2) to type-II and finally to type-I (WS2 straddling Bi2O2Se) by increasing the thickness of the Bi2O2Se bottom layer from monolayer to multilayer. We verified this band architecture conversion using steady-state and transient spectroscopy as well as density functional theory calculations. Using this material combination, we further design a sophisticated band architecture incorporating both type-I (WS2 straddles Bi2O2Se, fluorescence-quenched) and type-I (Bi2SeO5 straddles WS2, fluorescence-recovered) alignments in one sample through focused laser beam (FLB). By programming the FLB trajectory, we achieve a predesigned localized fluorescence micropattern on WS2 without changing its intrinsic atomic structure. This effective band architecture design strategy represents a significant leap forward in harnessing the potential of TMD heterojunctions for multifunctional photonic applications.
"Emission wavelength selection via anomalous polarized fluorescence in ZnO-C nanowires", Nano Research, 17, 4489
Defect fluorescence from high aspect ratio semiconductor nanowires typically displays a weak polarization parallel to the nanowire’s long axis due to dielectric mismatch in high aspect ratio media. Instead, anomalous 2.2 eV defect fluorescence distinctly polarized perpendicular to the nanowire is observed and measured from carbon-incorporated zinc oxide nanowires. These observations are significant because polarized defect emissions with consistent polarization on a mesoscopic scale are uncommon. Through a systematic study and comparison of experimental results with density functional theory calculations, an oriented defect complex comprising carbon substituting on an oxygen site and an oxygen vacancy (CO-VO) is deduced to be responsible for the anomalous yellow fluorescence, demonstrating a method for relating atomic-scale defect geometry to mesoscopic properties. The anomalous emission can appear in both green- and red-fluorescing nanowires grown with different carbon concentrations, verifying the independence and uniqueness of the 2.2 eV emission. This allows for polarization-dependent emission wavelength selection from a single nanowire.
"Upcycling fish scales through heating for steganography and Rhodamine B adsorption application", Nature communications, 14, 6508
With increasing population and limited resources, a potential route for improving sustainability is increased reuse of waste materials. By re-looking at wastes, interesting properties and multifunctionalities can be discovered in materials previously explored. Despite years of research on bio-compatible fish scales, there is limited study on the fluorescence property of this abundant waste material. Controlled denaturation of collagen and introduction of defects can serve as a means to transform the fluorescence property of these fish scale wastes while providing more adsorption sites for pollutant removal, turning multifunctional fish scales into a natural steganographic material for transmitting text and images at both the macroscopic and microscopic levels and effectively removing Rhodamine B pollutants (91 % removal) within a short contact time (10 minutes). Our work offers a glimpse into the realm of engineering defects-induced fluorescence in natural material with potential as bio-compatible fluorescence probes while encouraging multidimensional applicability to be established in otherwise overlooked waste resources.
"Multi-dimensional dynamic fluorescence readout from laser engineered In2O3 nanowire micropatterns", J. Mater. Chem. C, 11, 5271
Laser-induced microscale reactions are an excellent means to obtain controllable, small-scale insights into nanomaterial properties. Importantly, the opportunity for a comprehensive understanding of the material's optical origins allows for refined engineering of material luminescence. Modifying an array of standing indium oxide (In2O3) nanowires with a focused laser beam, we report newfound yellow and blue fluorescence emanating from the sample. Evaluated through a broad range of laser conditions, the laser-induced yellow component was found to relate to oxygen inclusions, while the blue fluorescence overlayer originated from oxygen physisorption upon prolonged storage. Capitalizing on the versatility of the blue emission component under UV modulation, we demonstrate micropatterns with multiple layers of differentiated optical encryption features. The enhanced anti-counterfeiting capability allows improved complexity in an authentication process, involving the convergence of microscale patterning, dynamic color evolution and time-domain encoding as multilevel checkpoints in the verification process.
"Microstyling of Biofluorescence in Human Hair as Sustainable and Functional Waste", Advanced Photonics Research, 3, 2200161
Human hair is a huge untapped waste resource whose useful compounds require toxic and environmentally harmful chemicals to extract. Herein, the optical properties of human hair without using such chemicals, turning waste into a site-selective multicolored display, and a chemical sensor with a visual indicator through tunable fluorescence are transformed. The tunable fluorescence color, which includes both visible light and infrared components, is achieved using a scanning laser beam (microscopic) and hotplate heating at a low temperature of 360 °C for 3 min (macroscopic and large-scale production). These fluorescing hair readily detects methylene blue molecules within a concentration range of 10-12–10-21 M due to the formation of tryptophan byproducts and electron contributing pyrrolic nitrogen. This work's simple yet impactful consequence lays the foundation on which the industrial applicability of the functionalized human hair waste can be achieved, realizing a possible cyclical economy through sustainable resources.
"Dynamic Tuning of Moiré Superlattice Morphology by Laser Modification", ACSNano, 16, 8172
In artificial van der Waals (vdW) layered devices, twisting the stacking angle has emerged as an effective strategy to regulate the electronic phases and optical properties of these systems. Along with the twist registry, the lattice reconstruction arising from vdW interlayer interaction has also inspired significant research interests. The control of twist angles is significantly important because the moiré periodicity determines the electron propagation length on the lattice and the interlayer electron–electron interactions. However, the moiré periodicity is hard to be modified after the device has been fabricated. In this work, we have demonstrated that the moiré periodicity can be precisely modulated with a localized laser annealing technique. This is achieved with regulating the interlayer lattice mismatch by the mismatched lattice constant, which originates from the variable density of sulfur vacancy generated during laser modification. The existence of sulfur vacancy is further verified by excitonic emission energy and lifetime in photoluminescence measurements. Furthermore, we also discover that the mismatched lattice constant has the equivalent contribution as the twist angle for determining the lattice mismatch. Theoretical modeling elaborates the moiré–wavelength-dependent energy variations at the interface and mimics the evolution of moiré morphology.
"Multifaceted Approaches to Engineer Fluorescence in Nanomaterials via a Focused Laser Beam", Light: Advanced Manufacturing, 3, 4
Fluorescent nanomaterials have long been recognized as essential contributors to the advancement of material technologies. Over the years, the rapid expansion in this massive selection of materials has led to the emergence of systems with tunable and unique fluorescent properties, occupying pivotal roles across niche areas in imaging, photonics, micro-encryption, and steganographic applications. In recent years, research interest in the translation of laser-based operations towards the production and modulation of nanomaterial fluorescence has been reignited, owing to its ease of operation and low cost. In this paper, we summarize the assortment of laser operations for the fabrication, modification, and spatial positioning of various fluorescent nanomaterials, ranging from metallic nanoparticles, carbon dots, 2D ultrathin films to wide-bandgap nanomaterials, and upconversion nanocrystals. In addition, we evaluate the importance of laser-modified fluorescence for various applications and offer our perspective on the role of laser-based techniques in the forthcoming advancement of nanomaterials.
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