RU2541422C1 - Probe of atomic-powered microscope with nanocomposite radiating element doped by quantum points of nucleus-shell structure - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: cantilever is connected to an exploring needle, the top of which is connected to the sphere made from glass with nanometre pores, filled with quantum points of nucleus - shell structure coated with protective polymeric layer, transparent for the length of external electromagnetic radiation source and the stokes shifted wavelength generated by quantum points of nucleus - shell structure.

EFFECT: possibility of simultaneous combination of electromagnetic effect with measurement of mechanical response to this stimulating effect in one common point of the surface of the diagnosed object without impacting the neighbouring sections.

2 cl, 2 dwg

Description

The invention relates to measuring technique and can be used in probe scanning microscopy and atomic force microscopy for the diagnosis and study of nanoscale structures.

A known atomic force microscope probe for measuring the elastic modulus (Young's modulus) of biological objects and preventing damage to their surface, consisting of a cantilever with an attached probe needle, on top of which a ball with a diameter of 5 μm is fixed [1].

A disadvantage of the known technical solution is the inability to simultaneously combine electromagnetic effects with measuring the mechanical reaction (elastic modulus) to this stimulating effect at one common point on the surface of the diagnostic object without affecting neighboring areas.

The closest in technical essence is an atomic force microscope probe for mechanical determination of elasticity (Young's modulus) of blood cells, consisting of a cantilever with an attached probe needle, on top of which a hollow polymer microsphere with a diameter of 10 μm is fixed [2].

A disadvantage of the known technical solution is the inability to simultaneously combine electromagnetic effects with measuring the mechanical reaction (elastic modulus) to this stimulating effect at one common point on the surface of the diagnostic object without affecting neighboring areas.

The difference between the proposed technical solution and the foregoing is the use of a nanocomposite emitting element in the form of a glass sphere with a core-shell structure doped with quantum dots fixed on the top of the probe needle, which allows for optomechanical studies of nanoscale structures of materials with optomechanical properties and biological objects with photobiological properties.

The technical result is the possibility of a simultaneous combination of electromagnetic effects with the measurement of a mechanical reaction (elastic modulus) to this stimulating effect at one common point on the surface of the diagnostic object without affecting neighboring areas.

The technical result of the proposed invention is achieved by a combination of essential features, namely: an atomic force microscope probe with a nanocomposite emitting element doped with quantum dots of a core-shell structure, including a cantilever connected to a probe needle with a nanometer radius of curvature of the vertex, which is connected to a sphere made of glass with nanometer pores filled with quantum dots of the core-shell structure, the number of which is more than two, and is determined by the diameter of the sphere and count the number of pores capable of placing quantum dots without leaving their shells beyond the perimeter of the circle circumference, the sphere being attached to the probe by rigidly fitting the tip of the probe needle with a nanometer radius of curvature into one of the pores of a glass sphere with nanometer pores, the rest of the pores with filled quantum dots of the core structure the shell is covered with a protective polymer layer transparent to the wavelength of the external electromagnetic source of excitation of quantum dots of the core-shell structure and the wavelength with the Stokes shift quantum dots my core-shell structure, an external excitation source of quantum dots is fixed at the base of the cantilever and its radiation is oriented to the center of a glass sphere with nanometer pores filled with quantum dots core-shell structure.

The invention is illustrated in figure 1, which presents a probe of an atomic force microscope with a nanocomposite emitting element doped with quantum dots of the core-shell structure (remote element A is shown in figure 2). Figure 2 presents the extension element A (10: 1) on an enlarged scale and in section, explaining the design of the probe of an atomic force microscope with a nanocomposite emitting element doped with quantum dots of the core-shell structure.

An atomic force microscope probe with a nanocomposite emitting element doped with quantum dots of the core-shell structure (Fig. 1) consists of: a cantilever 1 connected to a probe needle 2, on top of which a glass sphere 3 with nanometer pores 4 doped with quantum dots 5 is fixed core-shell structures, the excitation of which is carried out by an external electromagnetic source of excitation of quantum dots 6 (for example, a laser diode) located at the base of the cantilever 1 with the radiation direction oriented 1, the substrate 7 with the diagnosed object 8 placed on it at the moment of its contact with the sphere 3 (elements 4, 5, 8 are shown on an enlarged scale in figure 2).

On the remote element A (10: 1) of FIG. 2, the elements are shown in section, where the glass sphere 3 with nanometer pores 4 filled with quantum dots 5 of the core-shell structure, in one of the nanometer pores 4 of the glass sphere 3, the tip of the probe 2 is rigidly fixed , under the glass sphere 3 there is a substrate 7 with the diagnosed object 8. The minimum diameter of the glass sphere 3 is determined by the minimum number of doped quantum dots 5 of the core-shell structure, which together form a nanocomposite emitting element, param whose electromagnetic radiation is determined by the class of the diagnosed object 8. The arrows indicate the directions of the incoming λ1 and converted λ2 by the radiation wavelength, where λ1 is the wavelength of external electromagnetic radiation to excite the quantum dots causing their luminescence, λ2 is the luminescence wavelength of the quantum dot shifted by Stokes shift relative to wavelength λ1.

Depending on the types of objects to be diagnosed, diagnostic methods (for example, the diagnosis of photosensitive visual tissues of biological objects), the quantum dots 5 of the core-shell structure used for doping can be both with the Stokes and anti-Stokes wavelength shifts of electromagnetic radiation relative to the external excitation source 6 (t i.e., the wavelength λ1 is greater than λ2 or λ1 is less than λ2). This condition is due to the requirement of noise immunity so that λ1 is outside the wavelength zone to which all the studied sections of the diagnosed object 8 react, and it was stimulated only by emission of quantum dots 5 of the core-shell structure with wavelength λ2, which causes a change in the elastic modulus of individual local sections of the diagnosed object 8 in the immediate vicinity of the point of contact of the sphere 3 with the object of diagnosis 8.

The absorption wavelength λ1 of a quantum dot 5 of the core-shell structure and the radiation wavelength λ2 of the quantum dot 5 of the core-shell structure is determined by its diameter (mainly from 2 to 20 nanometers), a combination of the core material and the shell material, their percentage, the protective transmission spectrum transparent polymer film and the manufacturing technology of the quantum dot of the core-shell structure. The wavelength of electromagnetic radiation of quantum dots, aimed at the object of diagnosis, can be both in the optical range and beyond, from ultraviolet to infrared radiation.

The core of the quantum dot 5 of the core-shell structure may, for example, include at least one material selected from the group consisting of, but not limited to, CdSe, CdS, ZnS, ZnSe, CdTe, CdSeTe, CdZnS, PbSe, AgInZnS and ZnO. The shell of the quantum dot 5 of the core-shell structure may include at least one material selected from the group consisting of CdSe, ZnSe, ZnS, ZnTe, CdTe, PbS, TiO, SrSe, and HgSe, but is not limited to these options.

To implement the invention, in addition to classical quantum dots of the core-shell structure, core-multi-shell quantum dots can also be used [3].

The manufacture of a nanocomposite emitting element is carried out by doping the glass sphere 3 with quantum dots 5 of the core-shell structure and is performed by the penetration of quantum dots into nanoscale pores 4 of the glass sphere 3. For example, the doping process can be carried out according to the known method by immersing the element from glass with nanometer pores into a solution of two or more quantum dots, followed by drying in air and filling the voids remaining between the quantum dots with resin [4].

An atomic force microscope probe with a nanocomposite emitting element doped with quantum dots of the core-shell structure works as follows: a cantilever 1 with a probe needle 2 is fed to the diagnostic object 8 located on the substrate 7 and presses on it, obtaining data on the elastic properties of the object Diagnostics 8, before and after the inclusion of an external source of excitation of 6 quantum dots with a wavelength of λ1. As a result, quantum dots 5 excite the surface of the diagnosed object 8 with a wavelength of λ2, determined depending on the selected material of the quantum dot 5 and the ratio of the diameter of the core to the thickness of its surrounding shell. Depending on the required modes, diagnostics can take place both in the continuous luminescence mode and in the pulsed fluorescence mode (i.e., illumination of the local part of the diagnosed object only by radiation of λ2 quantum dots in the interval equal to the time of their fluorescence after turning off the external optical source for 6 s to exclude extraneous light and interference).

The proposed probe design with a nanocomposite emitting element doped with quantum dots of the core-shell structure also provides the ability to measure the topological distribution of the correlation of changes in the Young's modulus depending on the stimulating effect of a certain wavelength of electromagnetic radiation at each point when scanning the surface of the diagnostic object with an atomic force microscope X, Y coordinates, directly located under the radiating sphere. This allows you to detect and study individual photosensitive sections of biological objects and nanostructures that change their mechanical properties and dimensions under the influence of point electromagnetic radiation, which previously could not be done with known probes.

Information sources

1. D.V. Lebedev, A.P. Chuklanov, A.A. Bukharaev, O.S. Druzhinina. Measurement of the Young's modulus of biological objects in a liquid medium using a special probe of an atomic force microscope // Letters in ZhTF. - 2009 - T.35. Issue 8 - S.54-61.

2. Patent RU 2466401 C1, 10.11.2012, G01N 33/49. A method for determining the elasticity of blood cells.

3. Patent Application Publication Pub. No .: US 20120315391 A1 Pub. Date: Dec. 13, 2012, QUANTUM DOTS HAVING COMPOSITION GRADIENT SHELL STRUCTURE AND MANUFACTURING METHOD THEREOF.

4. Patent Application Publication Pub. No .: US 20130011551 A1 Pub. Date: Jan. 10, 2013, QUANTUM DOT-GLASS COMPOSITE LUMINESCENT MATERIAL AND MANUFACTURING METHOD THEREOF.

Claims (2)

1. An atomic force microscope probe with a nanocomposite emitting element doped with quantum dots of a core-shell structure, comprising a cantilever connected to a probe needle with a nanometer radius of curvature of the vertex, which is connected to a sphere, characterized in that the sphere is made of glass with nanometer pores, filled with quantum dots of the core-shell structure, the number of which is more than two, and is determined by the diameter of the sphere and the number of pores that can accommodate quantum dots without leaving their shells perimeter p of the sphere’s circumference, the sphere being attached to the probe by rigidly fitting the tip of the probe needle with a nanometer radius of curvature into one of the pores of the glass sphere with nanometer pores, the remaining pores with filled quantum dots of the core-shell structure are covered with a protective polymer layer transparent to the external wavelength electromagnetic source of excitation of quantum dots of the core-shell structure and wavelength with Stokes shift generated by quantum dots of the core-shell structure. 2. The probe according to claim 1, characterized in that the external source of excitation of the quantum dots is fixed at the base of the cantilever and its radiation is oriented to the center of the glass sphere with nanometer pores filled with quantum dots of the core-shell structure.

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