One-step Laser Process Research Articles

Laser-formed nanoporous graphite anodes for enhanced lithium-ion battery performance

Lithium-ion batteries are pivotal in modern energy storage, commonly utilizing graphite anodes for their high theoretical capacity and long cycle life. However, graphite anodes face inherent limitations, such as restricted lithium-ion storage capacity and slow diffusion rates. Enhancing the porosity of graphite and increasing d-spacing in expanded graphite anodes have been explored to improve lithium-ion diffusion and intercalation. Recent advancements suggest that nanoscale modifications, such as utilizing nano-graphite and graphene, can further enhance performance. Laser processing has emerged as a promising technique for synthesizing and modifying graphite and graphene-related materials, offering control over surface defects and microstructure. Here, we demonstrate an industrially compatible one-step laser processing method to transform a nano-graphite and graphene mixture into a nanoporous matrix, significantly improving lithium-ion battery performance. The laser-processed anodes demonstrated significantly enhanced specific capacities at all charge rates, with improved relative performance at higher charge rates. Additionally, long-term cycling at 1 C showed that laser-processed cells outperformed their non-processed counterparts, with specific capacities of 323 and 241 mAh/g, respectively.

Laser Fabrication of Multi-Dimensional Perovskite Patterns with Intelligent Anti-Counterfeiting Applications.

Perovskites have gained widespread attention across various fields such as photovoltaics, displays, and imaging. Despite their promising applications, achieving precise and high-quality patterning of perovskite films remains a challenge. In this study, femtosecond laser direct writing technology is utilized to achieve rapid and highly precise micro/nanofabrication on perovskites. The study successfully fabricates multiple structured and emission-tunable perovskite patterns composed of A2(FA)n-1PbnX3n+1 (A represents a series of long-chain amine cations, and X = Cl, Br, I), encompassing 2D, quasi-2D, and 3D structures. The study delves into the intricate interplay between fabrication technology and the growth of multi-dimensional perovskites: higher repetition rates, coupled with appropriate laser power, prove more conducive to perovskite growth. By employing precise halogen element design, the simultaneous generation of two distinct color quick-response (QR) code patterns is achieved through one-step laser processing. These mirrored QR codes offer a novel approach to anti-counterfeiting. To further enhance anti-counterfeiting capabilities, artificial intelligence (AI)-based methods are introduced for recognizing patterned perovskite anti-counterfeiting labels. The combination of deep learning algorithms and a non-deterministic manufacturing process provides a convenient means of identification and creates unclonable features. This integration of materials science, laser fabrication, and AI offers innovative solutions for the future of security features.

Enhancing efficiency of interfacial solar steam generation with biomimetic hierarchical porous graphene activated by NaOH

Interfacial solar steam generation (ISSG) provides a low-cost and green route to produce clean drinking water, meeting the urgent demand in remote and off-grid regions. To fabricate high-efficiency ISSG devices, researchers have harnessed graphene as an effective photothermal material of ISSG devices. However, the intricate fabrication and pristine hydrophobicity of graphene still limits the efficiency of ISSG devices. In this work, we present an approach to enhance the efficiency of ISSG using biomimetic hierarchically porous laser-induced graphene (LIG), activated by NaOH. The method involves one-step laser processing of polyimide films accompanied by NaOH activation, creating porous graphene structures with enhanced water wicking and evaporation rates. The optimal sample, activated by 5 M NaOH solution, exhibited superior evaporation performance at 2.41 kg/(m2·h) under one-sun irradiation. This advancement offers a promising avenue for cost-effective and efficient ISSG devices.

One-step process to obtain manganese-assisted laser-induced multi-layer graphene-like carbon supercapacitor

Laser-induced graphene (LIG) technology has made it possible to prepare graphene-based supercapacitors on a large scale and at low cost. However, the performance of graphene-based supercapacitors fabricated solely by laser still has a great potential for improvement. In this work, we obtained high-performance supercapacitors based on manganese-assisted laser-induced multi-layer graphene-like carbon (MLIGC) by a simple process. Poly-(m-phenylene isophthalamide) (PMIA) papers treated with modifier (KMnO4) were used as substrates. Modifier not only deepened the cross-sectional carbonization and achieveed uniform dispersing of manganese oxide nanoparticles, but also changeed the surface properties of MLIGC. Benefit from the hybrid structure of manganese oxide nanoparticles uniformly dispersed inside multi-layer graphene-like carbon (LIGC) prepared by one-step laser process, the combination of electric double-layer capacitance and pseudocapacitance allows for a further breakthrough in capacity while maintaining excellent cycling stability. Specifically, the supercapacitors achieve an area capacity of 72.4 mF cm−2 at 0.2 mA cm−2, which is 25 times higher than the control. In addition to the significant capacity increase, the addition of the modifier also achieveed a significant impedance reduction (almost one ninth of the control) and demonstrateed excellent cycling stability (nearly 100 % capacity retention after 7500 cycles at 10 mA cm−2). More importantly, the method is simple, fast, low-cost and high-efficiency, which provides a new path for the large-scale preparation of planar carbon-based supercapacitors.

In situ laser synthesis of Pt nanoparticles embedded in graphene films for wearable strain sensors with ultra-high sensitivity and stability

Carbon-based materials have recently attracted tremendous attention for their applications in highly sensitive wearable devices for human motion monitoring. Embedding rare metal nanoparticles such as Au, Ag, and Pt has been proved to significantly improve the sensitivity of the carbon-based strain sensors. However, the existing method to prepare nanoparticles usually involves multi-step, time-consuming procedures. Here, we report a facile one-step laser process to synthesize porous 3D graphene structures embedded with Pt nanoparticles. This is achieved by irradiating an ultraviolet (355 nm) picosecond laser on a film formed with a mixture of polybenzimidazole (PBI) and Pt(acac)2 solution to simultaneously induce the formation of graphene and reduction of the Pt precursor. The assembled strain sensor with loaded Pt nanoparticles in laser-induced graphene (Pt/LIG) demonstrates ultra-high sensitivity (a gauge factor, GFmax ≈ 489.3) and a wide strain range up to 20%. Additionally, the strain sensor with an optimized concentration of Pt(acac)2 has low hysteresis, minor lag errors, and a highly stable response (>5000 cycles). Various human motion signals are detected, from subtle physical activities (including chewing muscles movement, pulse beating) to large-scale limb track (finger bending, knee movement, and waist extending). This one-step laser process is facile, rapid, and potentially scalable for the mass production of high-performance wearable strain sensors.

Platinum nanoparticles supported on reduced graphene oxide prepared in situ by a continuous one-step laser process

A large research emphasis is still placed on improvement of production routes of nanosized materials with enhanced catalytic properties. Here we developed a continuous process for generation of platinum (Pt) nanoparticles supported on reduced graphene oxide (rGO) in situ via pulsed laser ablation in liquid (PLAL) dispersion of rGO. This in situ PLAL technique is a single step procedure that allows the synthesis of heterogeneous catalysts with a simultaneous control of particle size and mass loading. By this method, Pt particles with mean particle diameters around 2.5 nm and in a regime of 3–4 nm have been produced in ethanol and saline water, respectively, and adsorbed on rGO with up to 50 wt%. Both inorganic and organic solvents used during in situ synthesis lead to production of CO tolerant Pt/rGO catalysts, which are relevant for fuel cell applications due to the remarkably low CO desorption temperatures around 65–80 °C.

A one-step laser process for rapid manufacture of mesoscopic perovskite solar cells prepared under high relative humidity

A one-step laser process is applied to fabricate mesoporous and compact TiO2 films in 1 min for perovskite solar cells.

Tunable graphene oxide reduction and graphene patterning at room temperature on arbitrary substrates

Over the past decade, reports of graphene-based devices have increased exponentially due to the superior characteristics and unique advantages that graphene introduces. However, the cost-effective growth and patterning of graphene is always a challenge for large-scale graphene-based device applications. Here we report a universal method based on one-step laser scribing technology for quick synthesis and patterning of large-scale multi-layer graphene films from graphene oxide films using a 650 nm commercial laser on arbitrary substrates. Moreover, by tuning the laser power, three distinct regions are found: growth, transition and etch regions. SEM, optical microscopy, Raman spectroscopy, electrical conductance testing, and transmittance measurements confirm the presence of three such regions. These tests show that the reduction of GO happens at low power and the gasification of LSG into CO2 happens at high power. Furthermore, a theoretical model is established to analyse the thickness changes under different laser power. This laser processing method could significantly simplify the processing steps and reduce the cost for the fabrication of graphene-based devices. This work also demonstrates promising applications for scalable manufacturing of graphene-based devices using one-step laser processing at standard temperature and pressure.

Single-Crystalline Rutile TiO2 Hollow Spheres: Room-Temperature Synthesis, Tailored Visible-Light-Extinction, and Effective Scattering Layer for Quantum Dot-Sensitized Solar Cells

A general synthesis of inorganic single-crystalline hollow spheres has been achieved through a mechanism analogous to the Kirkendall effect, based on a simple one-step laser process performed at room temperature. Taking TiO(2) as an example, we describe the laser process by investigating the influence of experimental parameters, for example, laser wavelength, laser fluence/irradiation time, liquid medium, and concentration of starting materials, on the formation of hollow spheres. It was found that the size-tailored TiO(2) hollow spheres demonstrate tunable light scattering over a wide visible-light range. Inspired by the effect of light scattering, we introduced the TiO(2) hollow sphere's scattering layer in quantum dot-sensitized solar cells and achieved a current notable 10% improvement of solar-to-electric conversion efficiency, indicating that TiO(2) hollow spheres are potential candidates in optical and optoelectronic devices.

High-strength fiber Bragg gratings for a temperature-sensing array

We have successfully demonstrated a one-step laser process of fabricating fiber Bragg grating arrays directly through fiber buffer. A new polysiloxane-based buffer provides high 244-nm transmission and showed no degradation due to UV irradiation or thermal annealing as verified by Weibull analysis of tension tests. The FBG array can withstand over 400-kpsi tension tests and 220degC temperature. The spectral quality of the FBG is compatible with the FBGs currently used by the sensing industry and, therefore, can be interrogated with existing instruments. The laser fabrication process is robust with no coating, stripping, or recoating required