RU197802U1 - Device for the formation of nanoparticles by pulsed laser ablation of a target in a liquid - Google Patents

Abstract

The utility model relates to the field of nanoparticle formation by pulsed laser ablation of a target in a liquid medium and can be used in chemical and physical experiments, as well as in the field of biomedicine. A device for forming nanoparticles by pulsed laser ablation of a target in a liquid comprises an ablation cuvette mounted above a magnetic stirrer for pumping a liquid medium with an internal target. The cuvette is closed with a transparent glass lid and contains a fluoroplastic stirrer with a magnetic core, a wall restricting the movement of the specified fluoroplastic agitator, and a platform for securing the target located between the wall of the cell and the wall restricting the motion of the fluoroplastic agitator. The cuvette is mounted on two perpendicularly located automated mechanical translators that are capable of connecting to a personal computer and moving the cuvette with the target mounted on the site at a right angle of incidence of laser radiation to process the entire surface of the target with laser radiation of the same intensity. The design is simplified, the efficiency of the process of pulsed laser ablation of a solid target in a liquid medium is increased. 1 ill.

Description

Technical field

A device for the formation of nanoparticles by pulsed laser ablation of a target in a liquid refers to the region of formation of nanoparticles by pulsed laser ablation of a target in a liquid medium, and virtually any material (metal and non-metal) can act as a target. The resulting solutions with nanoparticles can be used in chemical and physical experiments, as well as in the field of biomedicine.

State of the art

The laser ablation method is widely used among other methods of producing nanoparticles, ensuring the chemical purity of the process, as well as the possibility of changing within a wide range the structural, optical and electronic properties of the obtained nanoparticles by varying the ablation conditions (such as laser radiation parameters, buffer medium parameters). In addition, this method allows the formation of nanoparticles from virtually any material. It is possible to obtain metal nanoparticles (gold, silver) and semiconductor nanoparticles (silicon, germanium, silicon carbide). In addition to the fundamental interest, the properties of the formed particles are of practical interest. For example, silicon and silicon carbide nanoparticles can be used as photoluminescent labels and contrast agents in optical coherence tomography due to their optical properties, as well as biocompatibility and non-toxicity of silicon. In this regard, the creation of a facility to improve the ablation process and increase its effectiveness is of undoubted interest and practical significance.

A device for positioning a target for a device for producing nanoparticles by laser ablation is known (RU 155439 U1, 03/13/2015). This device allows you to mount the target to the installation in a vacuum way and then continuously carry out the process of synthesis of nanoparticles by moving the laser beam on the surface of the target. The means of vacuum fixing the target to the site is a venturi nozzle.

The disadvantage of this device is the lack of movement of the target in a plane perpendicular to the plane of incidence of the laser radiation. To process the entire target, the laser beam moves along the target surface, which leads to a shift in focusing and different intensities of the surface treatment when the laser beam passes through various places of a fixed optical lens. Different intensity of the incident radiation can lead to a change or failure of the ablation mode.

An apparatus for laser ablation in a liquid (USPatent # 8246714 08/21/2012) eliminates the disadvantage of the previous device and contains a translator that moves the cell with the target, while the laser beam remains stationary. The radiation used is IR laser radiation with a pulse duration of pico and femtoseconds with a repetition rate of 1 kHz. However, radiation is introduced from above through the thickness of the solution, while there is no glass or lid to prevent spraying of the solution during the experiment, which is a disadvantage of this method. As a result, splashing leads to contamination and damage to optical elements, such as a focusing lens, as well as the formation of inhomogeneities on the surface of the liquid.

Closest to the claimed is a device for producing a colloidal solution of nanoparticles in a liquid by laser ablation (RU 130402 U1, 07.20.2013). This device includes an ablation cuvette, a metal target with the ability to scan laser radiation on the surface of the target, a magnetic stirrer that allows you to mix the solution in the cell to obtain a homogeneous solution. The device comprises a fluid pumping system from two tanks: for the initial fluid and for the solution of nanoparticles. The main disadvantage of this installation is the lack of a mechanism for attaching a solid target. When pumping a fluid flow, as well as in the process of scanning the target and the incidence of laser radiation, a water hammer occurs during the passage of the liquid layer, and the target becomes possible to shift. The shift of the target can result in repeated laser radiation entering the treated zone, or laser radiation beyond the processing limits, which leads to damage to the system. In addition, a radiation drop at an angle leads to a violation of the Gaussian intensity distribution in the plane of the laser spot, which can reduce the efficiency of the ablation process and reduce the concentration of the formed solution. As a solution to the problem of target displacement, one can cite a target positioning device for a laser ablation nanoparticle production unit containing a cuvette with tubes for feeding and discharging

liquid intended for removal of ablation products, and a platform placed in the cell for fixing the target on it and means for fixing the target on the site (US 2013/0125674 A1, 05.23.2013). However, the mounting of the target in this device is carried out mechanically - with clamps, which leads to a limitation of the treated area of the target, which reduces the efficiency of using the surface of the target.

Utility Model Essence

The inventive utility model eliminates the disadvantages characteristic of the above analogues.

The objective of this utility model is to develop such a device for the formation of nanoparticles by pulsed laser ablation of a target in a liquid, which would allow the fixed target to be moved in the xy plane at a right angle of incidence of the laser radiation, and also to avoid splashing of the liquid buffer medium and the appearance of inhomogeneities on its surface and contamination of the optical elements of the system.

The problem is solved in that the device for the formation of nanoparticles by pulsed laser ablation of a target in a liquid, consisting of an ablation cuvette mounted above a magnetic stirrer for pumping a liquid medium, contains a platform for mounting the target in the cuvette, the cuvette itself is mounted on two perpendicular automated mechanical translators moving the cuvette with the target in the xy plane at a right angle of incidence of the laser radiation, and on top of the cuvette is closed with transparent glass.

The means of fixing the target on the site between the wall of the cuvette and the wall restricting the movement of the fluoroplastic stirrer with a magnetic core, allows you to firmly fix the target of a certain shape (18 × 13 cm) and prevent its displacement under the influence of hydraulic shock in the liquid during processing. The pad and the cuvette are made of chemically pure and resistant materials Teflon and polypropylene, respectively. This composition ensures the purity of the solutions formed at the outlet and the absence of various impurities during the ablation process. The presence of two perpendicular translators allows moving the target in the xy plane at a right angle of incidence of the laser radiation, thereby providing processing of the entire surface of the target with laser radiation of the same intensity. The presence of glass on the surface of the cuvette helps prevent liquid spatter

buffer medium and contamination of the optical elements of the system in the process of exposure to the target of laser radiation passing through this glass.

Brief Description of the Drawings

The utility model is illustrated by the diagram of the claimed device (Fig. 1). The device consists of a cuvette 1 with a cover of transparent (for an optical signal) glass 2, a platform for attaching a target 3, a fluoroplastic stirrer with a magnetic core 4, a magnetic stirrer MM-01 5, a mechanical automated translator 6 for moving the cuvette with the axis mounted inside the target X, of a mechanical automated translator 7 for moving a cuvette with a target mounted on the Y axis, a personal computer 9 used to control mechanical translators.

Utility Model Implementation

The device operates as follows.

Before ablation begins, the target (metal or non-metallic) is placed in cuvette 1 and fixed on site 3 between the wall of the cuvette and the wall restricting the movement of the fluoroplastic agitator with magnetic core 4. The size of the target is 18 × 13 cm. The size of the liquid layer above the target surface is 2-3 mm. In order to minimize the chemical interaction between the liquid medium and the cuvette, polypropylene and fluoroplastic are selected as the material for the cuvette. A liquid buffer medium is poured into the cuvette, while the volume of the liquid to be filled is 15 ml. On top of the cuvette is closed by glass 2, transparent to optical radiation. In order to avoid screening of the laser pulse by ablation products, a system for pumping a liquid medium was used in the cuvette. For this, the cuvette is placed directly above the magnetic stirrer 5, and a fluoroplastic stirrer with a magnetic core 4 is placed in the cuvette. At the same time, the pumping speed of the medium is 2-3 millimeters per second. The laser radiation focuses on the target, passing through the optical lens 8. When the laser pulse is applied to the target surface, the surface gradually degrades and degrades, while the ablation efficiency decreases. To avoid this, it is necessary to use a new target region for each laser pulse. For this, the cuvette moves in the XY plane thanks to mechanical automated translators 6 and 7. The translators are connected to a personal computer 9, on which the speed of the translators is set. X axis constant speed

translator 6 is 8 mm / min. Such an ablation regime corresponds to 30% of the area of overlapping of traces from the influence of laser pulses, which according to published data corresponds to the most optimal mode of using the target surface. The Y axis moves 1 mm when the length of the target is exhausted. Thanks to the movement of the translators, it is possible to process the entire surface of the target. The presence of transparent glass on the surface of the cuvette prevents the solution from splashing during the experiment, the occurrence of inhomogeneities on the liquid surface and contamination of the focusing lens during pulsed laser ablation.

Claims (1)

A device for forming nanoparticles by pulsed laser ablation of a target in a liquid, containing an ablation cuvette mounted above a magnetic stirrer for pumping a liquid medium with an inside target, characterized in that the cuvette is closed by a transparent glass lid and contains a fluoroplastic stirrer with a magnetic core, a wall bounding the movement of the specified fluoroplastic stirrer, and the platform for fixing the target, placed between the wall of the cell and the wall restricting the movement of the fluoroplastic stirrer, while the cuvette is mounted on two perpendicularly located automated mechanical translators, which are configured to connect to a personal computer and move the cuvette with installed on the site the target at a right angle of incidence of the laser radiation for processing the entire surface of the target with laser radiation of the same intensity.

Images