LT6558B - Method for generation and distribution of nanoparticles on a surface of transparent substrate - Google Patents

Abstract

The invention relates to the generation of nanoparticles having magneto-optical properties on different transparent surfaces and their uniform arrangement on a transparent substrate surface by laser radiation. In order to simplify the embodiment of the apparatus and extend the application area on a transparent material substrate, a thin bimetallic layer having magnetic-optical properties directed and focused on the laser radiation that has melted the layer is formed. The configuration of the molten zone is selected by moving the pallet in the direction of laser radiation. Hydrodynamic phenomena occurring in laser beam and molten bimetallic zones cause the self-organization of the molten bimetallic liquid material into droplets on a transparent substrate, which, upon cessation of laser radiation, cools down and becomes nanoparticles having magnetic-optical properties.

Description

Technical field

The invention relates to the generation of nanoparticles on various transparent surfaces and their uniform distribution on a transparent substrate surface using laser radiation. More particularly, the invention relates to the generation and even distribution of nanoparticles having magneto-optical properties, e.g. on indium tin oxide (ITO) glass, and can be used in the design of magneto-plasmonic rulers, electrochemical or magnetoplasmonic sensors.

State of the art

International Application No. VV02003073444 A1, Published 2003 On September 4, 2006, the generation of Fe / Au nanoparticles by electrical discharge was described. The generated nanoparticles are supermagnetic with high magnetic sensitivity at room temperature and can be easily functionalized for a variety of applications by attaching organic molecules to their surface. In this case, the gold-iron target is vaporized by an electric current discharge. The molten target vapor is cooled by a convective stream of argon, helium or nitrogen gas to form solid metal nanoparticles containing iron and gold. The ratio of gold to iron in formed nanoparticles is random. The cooled Fe / Au nanoparticles are placed in an aqueous or organic solution containing molecules that can attach to the surface of the nanoparticles and protect them from aggregation and functionalize them.

U.S. Pat. US20130183492 A1, published in 2013; On July 18, 2006, the formation of metallic nanoparticles using inductively coupled plasma and their uniform and reproducible distribution on a substrate was described. In this case, the thin metal layer is treated with inductively coupled plasma to obtain an even distribution of nanoparticles on the substrate. The distance between nanoparticles and their size is controlled by changing the power of the inductively coupled plasma or the processing time of the process. The nanoparticles thus formed have a size ranging from 10 nm to 100 nm.

U.S. Pat. US8802234 B2, Publication 2014. August 12, 2006, describes the generation of composite nanoparticles using laser ablation. In this case, composite nanoparticles are generated by ablating the composite target in a special-shaped fluid container while moving it by means of a sliding table. Moving the container creates a fluid movement that is used to collect the generated nanoparticles from the container as well as to cool them. In this way, nanoparticles with magneto-optical properties, which are particularly attractive for biomedical applications, can be generated.

U.S. Pat. US8865574 B2, published 2014 On October 21, 2000, a method for deposition of nanoparticles in a liquid by applying an electric field to a suspension of nanoparticles and simultaneously heating them is described. This method is based on the phenomenon of electrophoresis. In this case, the nanoparticles are given a surface charge so that they can migrate to a charged substrate that acts as an electrode when exposed to an electric field. Nanoparticles can be of various types (both polymeric, metallic and ceramic) but must be able to exert a surface charge.

U.S. Pat. US20020018861 A1, published Feb. 14, 2002, describes the deposition of nanoparticles on a substrate and their conversion into a thin metal or metal oxide film. In this case, the nanoparticles are deposited in a precursor solution that is deposited on a substrate, and the precipitated nanoparticles are converted into a thin metal or metal oxide film by photochemical reaction or ion or electron beam. This results in a thin film of metal or metal oxide with embedded nanoparticles. Using masks or directional ion or electron beams, various patterns can be formed on a metal or metal oxide film. In addition, changing the composition of the atmosphere in which the film patterns are formed can alter the properties of the metal or metal oxide formed. Such films can be used in a variety of applications such as diffusion barriers, capacitors, electrodes of dielectric or magnetic materials.

U.S. Pat. US8020508 B2, published 2011 On September 20, 2005, a method for deposition of nanoparticles on a substrate using a device specifically designed for this purpose is described. The apparatus consists of a vacuum chamber, a sample heating mechanism, a nanoparticle hopper and a mixer and a narrow orifice. With this device, the size of the deposited nanoparticles can be controlled by varying the pressure difference inside and outside the chamber. In this case, nanoparticles of various types and shapes can be precipitated without any melting, curing or sublimation processes, and no electrical or magnetic sources are used.

U.S. Pat. US20080006524 A1, published January 2008 January 10, 2006 describes the generation and deposition of controlled size nanoparticles on a substrate in a vacuum chamber using laser ablation. Nanoparticle size control is performed by measuring the ionic flux of the bonded material.

In this case, the target and the substrate on which the deposited nanoparticles are placed in a vacuum chamber. The target is ablated by selecting a specific energy density for the laser radiation. For a given range of laser radiation energy densities, the ion flux is constant. In this range, controlled-sized nanoparticles can be generated. The generated nanoparticles of controlled size are deposited on a substrate.

The above-described methods for generating nanoparticles using electrical discharge and laser ablation are known. In this case, the nanoparticles are generated in liquid or gas rather than directly on the substrate. The uniform deposition of nanoparticles in a liquid or gas on a substrate is a complex process and requires sophisticated and specially designed devices (US8020508 B2) or additional processing of nanoparticles. Other simple nanoparticle deposition methods (e.g., spin-casting) result in uneven distribution of nanoparticles on a substrate. Inductively coupled plasma can be used to generate and evenly distribute nanoparticles on a substrate (US20130183492 A1), but in this case, the selective gelling of nanoparticles is not possible because the nanoparticles are formed over the entire surface of the substrate.

Resolving a technical issue

The present invention seeks to simplify the method of generating nanoparticles and to extend its field of application by enabling the uniform deposition of nanoparticles on transparent smooth and curved surfaces, both selectively and over the entire surface, and to generate both types of particles and adapt them to generate nanoparticles.

Disclosure of Invention

The essence of the solution according to the present invention is that in the method of generating and distributing nanoparticles on transparent surfaces using laser radiation to generate nanoparticles, a thin bimetallic layer having magneto-optical properties is formed on the transparent substrate, directing laser radiation to the transparent substrate focuses in the formed bimetallic layer, selects the energy and density of the laser radiation so that the areas of the bimetallic layer exposed to the laser radiation melts on the transparent material substrate and becomes liquid, the transparent substrate with the formed bimetallic layer and molten bimetallic layer areas on a transparent substrate, laser exposed and molten bimetallic layer hydrodynamic regions bours bimetal causes molten material layer of self-organization the liquid drops on transparent substrates which have ceased to operate the laser cools and becomes nano-particles having a magneto-optical properties.

The thin bimetallic layer formed is of Fe and Au or of Au and Fe.

The formed thin bimetallic layer with magneto-optical properties is selected from the following metals: silver (Ag), copper (Cu), nickel (Ni), cobalt (Co), gadolinium (Gd).

The bimetallic layer has a metal layer thickness of up to 10 nm.

The metal layers of the bimetallic layer may be of the same or different thickness.

The bimetallic layer on a transparent substrate is formed by physical vapor deposition or chemical vapor deposition or electrodeposition.

Transparent substrate surface on which the bimetallic layer is formed can be smooth or of varying curvature

Utility of the invention

The advantage of the present invention is that the implementation of the method does not require complicated and specially designed equipment. The method is suitable both for the whole surface and for the selective generation and even distribution of not only one kind of nanoparticles, but also nanoparticles with magneto-optical properties on the desired transparent surface which can be both smooth and of any curvature. In the proposed manner, nanoparticles can be selectively generated and deposited at the desired substrate location, rather than just the entire substrate. In addition, the choice of materials for the bimetallic layer can alter the composition of nanoparticles, forming more complex nanoparticle derivatives that can be integral parts of magneto-plasmonic devices.

The invention is explained in more detail in the drawings, wherein

FIG. Figure 1 is a schematic diagram of the generation and uniform deposition of nanoparticles with magneto-optical properties on transparent surfaces.

Fig. 2 shows the principle of formation of nanoparticles with magneto-optical properties,

Figure 3 shows an example of generated nanoparticles on an ITO glass using the described technology.

Example of embodiment of the invention

The directional laser beam 2 generated by the laser source 1 passes successively through the phase plate 3 and the Bruster angle polarizer 4 for controlling the average power of the laser beam, from which the reflected radiation is absorbed by the trap 5. The laser beam 2 , consisting of a system of diffusing lens 6 and lens 7 which is transparent to the emitted laser radiation. After passing the expander 2, the radiation is directed to the mirror 8, from which the reflected laser radiation is directed through the focusing lens 9 towards the transparent substrate 12 on which the bimetallic layer is evaporated (10 and 11). The thickness of the metal layers forming the bimetallic layer is up to 10 nm and the thickness ratio can vary.

With the aid of an expander, the diameter of the laser beam on the focusing lens 9 can be controlled and, at the same time, the intensity incident on the bimetallic layer 10, 11 and the laser treatment area. The laser beam 2 is focused by a long focal length lens 9 in the bimetallic layer 10, 11. The transparent substrate 12 with the evaporated bimetallic layer 10, 11 can be shifted at a certain speed 13 relative to the laser beam to selectively generate nanoparticles on the transparent substrate 12. The bimetallic thin layer 10, 11, composed of magnetic and optical properties having different metals (e.g., Fe and Au) and formed on a transparent substrate 12, is exposed to laser radiation. When exposed to laser radiation, both metals melt and become liquid. In molten metal coatings, hydrodynamic phenomena occur which cause the liquid material to self-organize into droplets on a transparent substrate 12. When laser radiation ceases, the droplets cool, harden and become nanoparticles with magneto-optical properties. The distribution density of nanoparticles and their size depend on the thickness of the metal coatings.

Figure 2 shows the principle of the formation of nanoparticles with magneto-optical properties. A bimetallic thin layer consisting of different layers of metals 10 and

11, which has magnetic and optical properties and is formed on a transparent substrate 12, is exposed to laser radiation 2. Under the action of laser radiation 2, both metals melt and become liquid. In molten metal coatings, hydrodynamic phenomena occur which cause the liquid material to self-organize into droplets on a transparent substrate 12. The cooled droplets solidify and become nanoparticles 14 with magneto-optical properties.

Claims (7)

1 A method of generating and distributing nanoparticles on transparent surfaces, which employs laser radiation to generate nanoparticles, comprising the following sequence of operations: - forming on the transparent substrate (12) a thin bimetallic layer (10, 11) having magneto-optical properties, deflects and focuses the laser radiation (2) on the energy and density of the laser radiation (2) in the formed bimetallic layer (10,11); selects such that the areas of the bimetallic layer (10, 11) exposed to the laser radiation melt on the transparent substrate (12) and become liquid, the transparent substrate (12) with the formed bimetallic layer (10, 11) and the focused laser radiation with respect to the hydrodynamic effects of the molten bimetallic layer on the transparent substrate (12), the hydrodynamic phenomena occurring in the exposed and melted areas of the bimetallic layer (10, 11) result in the self-organization of the liquid material of the molten bimetallic layer tray, which when the laser stops working It cools down to radiation and becomes nanoparticles with magneto-optical properties. 2. A process according to claim 1, characterized in that the thin bimetallic layer formed (10,11) is made of Fe and Au or Au and Fe. 3. A process according to claim 1, characterized in that the thin bimetallic layer (10, 11) formed with magneto-optical properties is selected from the following metals: silver (Ag), copper (Cu), nickel (Ni), cobalt (Co). ), gadolinium (Gd) A process according to any one of claims 1 to 3, characterized in that the metal layer of the bimetallic layer (10,11) has a thickness of up to 10 nm. 5. A process according to any one of claims 1 to 4, characterized in that the metal layers of the bimetallic layer can be of the same or different thickness. 6. A process as claimed in any one of claims 1 to 5, wherein the bimetallic layer on the transparent substrate is formed by physical vapor deposition or chemical vapor deposition or electrodeposition. 7. A method as claimed in any one of claims 1 to 6, characterized in that the surface of the transparent material substrate on which the bimetallic layer is formed can be both smooth and of varying curvature.