CN112366236B - Light energy collecting microstructure, photosensitive element and optical device - Google Patents

Abstract

The application relates to a light energy collecting microstructure, a photosensitive element and an optical device. Wherein the light energy collecting microstructure comprises: a nanoparticle dimer array composed of periodically arranged nanoparticle dimers; the arrangement direction of the nano particle dimers is vertical to the propagation direction of incident light; the first nanoparticles and the second nanoparticles in the nanoparticle dimer are distributed along the propagation direction of incident light, and the first nanoparticles and the second nanoparticles are distributed in a staggered manner in the polarization direction of the incident light. Under the irradiation of incident light, two nanoparticles forming a nanoparticle dimer in the light energy collecting microstructure are respectively excited to form electric dipoles, local surface plasmon resonance is generated, and then the phenomenon of surface plasmon resonance enhancement due to coupling occurs, so that the light energy collecting efficiency can be obviously improved.

Description

Light energy harvesting microstructures, photosensitive elements and optical devices

technical field

The present application relates to the field of light energy collection, in particular to a light energy collection microstructure, a photosensitive element and an optical device.

Background technique

43 years ago, the first ruby laser was born. The optoelectronic technology triggered by this laser has brought earth-shaking changes to human life. Due to its excellent performance characteristics, optoelectronic technology has developed rapidly, forming a large number of industries based on optoelectronic technology, such as optical communication, optical display, optical storage, solar cells, etc. Regardless of the application, it is necessary to collect the incident light first, and then process or convert the collected incident light.

The traditional light energy harvesting method uses the photoelectric conversion function of the photosensitive element to transmit the incident light to the photosensitive element, and the photosensitive element converts the received light signal into an electrical signal. Due to the large loss of light energy in the collection process, under certain incident conditions, the light signals that can be converted into electrical signals by traditional photosensitive elements are limited, resulting in weaker output electrical signals. Usually, it is necessary to design a concentrating structure at the front end to increase the energy of the incident light, and design an amplifier circuit at the back end to amplify the electrical signal before outputting it.

Therefore, the traditional photosensitive element has the disadvantage of low energy collection efficiency.

Contents of the invention

Based on this, it is necessary to provide a light energy collection microstructure, a photosensitive element and an optical device with high energy collection efficiency in order to solve the above technical problems.

In the first aspect, a light energy collection microstructure is provided, including:

A nanoparticle dimer array, the nanoparticle dimer array is composed of periodically arranged nanoparticle dimers; the arrangement direction of the nanoparticle dimers is perpendicular to the propagation direction of the incident light; the nanoparticle dimers The first nanoparticles and the second nanoparticles in the body are distributed along the propagating direction of the incident light, and the first nanoparticles and the second nanoparticles are dislocated in the polarization direction of the incident light.

In one of the embodiments, the misalignment distance between the first nanoparticles and the second nanoparticles in the polarization direction of the incident light is not more than half of the smaller spacing between the nanoparticle dimers.

In one embodiment, the distance between the nanoparticle dimers is 370nm-1000nm.

In one of the embodiments, the first nanoparticles and the second nanoparticles are closely distributed in the direction of propagation of the incident light.

In one embodiment, the radii of the first nanoparticles and the second nanoparticles are 10 nm-100 nm.

In one embodiment, the nanoparticle dimer is an inert metal nanoparticle dimer.

In one embodiment, the ratio of the radius of the nanoparticles in the nanoparticle dimer to the lattice constant is 1:10-1:7.

In a second aspect, a photosensitive element is provided, including the above-mentioned light energy collection microstructure.

In a third aspect, an optical device is provided, including the above-mentioned photosensitive element.

The light energy collection microstructure includes a nanoparticle dimer array, and the nanoparticle dimer array is composed of periodically arranged nanoparticle dimers. Wherein, the arrangement direction of the nanoparticle dimers is perpendicular to the propagation direction of the incident light. The two nanoparticles in the nanoparticle dimer are distributed along the propagating direction of the incident light, and are dislocated in the polarization direction of the incident light. Under the irradiation of incident light, the two nanoparticles will be excited at the same time, forming electric dipole oscillation, resulting in localized surface plasmon resonance, and then coupling to promote the enhancement of surface plasmon resonance, which can significantly increase the light energy. collection efficiency.

Description of drawings

Fig. 1 is the schematic diagram of nanoparticle dimer array in one embodiment;

2 is a schematic diagram of a surface plasmon resonance absorption spectrum in an embodiment;

Fig. 3 is a schematic diagram of the positive and negative charge distribution of nanoparticle dimers in resonance mode in one embodiment;

Fig. 4 is a schematic diagram of spatial phase distribution and optical energy flow collection of nanoparticle dimers in three resonance modes in one embodiment.

Detailed ways

In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the application are given in the drawings. However, the present application can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of this application more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the specification of the application are only for the purpose of describing specific embodiments, and are not intended to limit the application.

It can be understood that the terms "first", "second" and the like used in this application may be used to describe various elements herein, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first nanoparticle could be termed a second nanoparticle, and, similarly, a second nanoparticle could be termed a first nanoparticle, without departing from the scope of the present application. The first nanoparticle and the second nanoparticle are both nanoparticles, but they are not the same nanoparticle.

It can be understood that "connection" in the following embodiments should be understood as "optical connection", "optical connection" and the like if the connected circuits, modules, units, etc. have optical signal or data transmission between each other.

When used herein, the singular forms "a", "an" and "the/the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprising/comprising" or "having" etc. specify the presence of stated features, integers, steps, operations, components, parts or combinations thereof, but do not exclude the presence or addition of one or more The possibility of other features, integers, steps, operations, components, parts or combinations thereof. Meanwhile, the term "and/or" used in this specification includes any and all combinations of the related listed items.

In one embodiment, a light energy collection microstructure is provided, comprising: a nanoparticle dimer array, the nanoparticle dimer array is composed of periodically arranged nanoparticle dimers; the nanoparticle dimer The arrangement direction and the propagation direction perpendicular to the incident light; the first nanoparticles and the second nanoparticles in the nanoparticle dimer are distributed along the propagation direction of the incident light, and the first nanoparticles and the second nanoparticles are polarized in the incident light Directional misalignment distribution.

Among them, nanoparticles, also known as ultrafine particles, are groups composed of a small number of atoms or molecules. It can be considered that the state of atoms on the surface of nanoparticles is closer to the gas state, while the atoms inside the particles may be arranged in an orderly manner. A nanoparticle dimer refers to a whole composed of two nanoparticles. Surface plasmons are electromagnetic oscillations formed by the interaction of free electrons and photons in the surface region of a material. Surface plasmon resonance refers to the phenomenon that surface plasmons propagate along the direction of the interface. The special structure of nanoparticles makes them have some special physical and chemical properties. Under the excitation of the light field, the free electrons in the nanoparticles vibrate collectively, and form electric dipoles with the positive charges in the lattice to produce localized surface plasmon resonance. The distribution of the first nanoparticles and the second nanoparticles along the propagation direction of the incident light means that the incident light cannot reach the first nanoparticles and the second nanoparticles at the same time, that is, there is a dislocation between the two in the propagation direction of the incident light, specifically Including: the projections of the first nanoparticle and the second nanoparticle in the polarization direction of the incident light are separated by a certain distance, tangent or overlapping. The dislocation distribution of the first nanoparticles and the second nanoparticles in the polarization direction of the incident light means that the connecting line between the centers of the first nanoparticles and the second nanoparticles does not coincide with the propagating direction of the incident light.

Specifically, please refer to FIG. 1 , which is a typical nanoparticle dimer array. In Figure 1, E is the polarization direction of the incident light, and k is the propagation direction of the incident light. The nanoparticle dimers 100 are aligned in x and y directions, perpendicular to the propagation direction k of the incident light. Among them, E coincides with the x direction, and k coincides with the z direction. The distance between two nanoparticle dimers in the x direction is P _x , and the distance in the y direction is P _y . Each set of nanoparticle dimers 100 consists of a pair of first nanoparticles 110 and second nanoparticles 120 . The displacement distance between the first nanoparticle 110 and the second nanoparticle 120 in the polarization direction of the incident light is Sx. It can be understood that, relative to the second nanoparticle 120, the first nanoparticle 110 can be dislocated along the positive direction of x, or can be dislocated along the negative direction of x, as shown in FIG. Particle 120 is dislocated along the positive direction of x.

Under the excitation of the incident light field, the first nanoparticle 110 and the second nanoparticle 120 in the nanoparticle dimer 100 are respectively excited to form electric dipoles, resulting in the first localized surface plasmon resonance and Second localized surface plasmon resonance. Since the first nanoparticle 110 and the second nanoparticle 120 are misaligned in the polarization direction of the incident light, the localized surface plasmon resonance of the two particles can realize resonance spectrum modulation within the range of the lattice constant through the grating coupling mode, The surface plasmon resonance enhancement phenomenon occurs to realize stable light energy continuous circulation and improve the light energy collection efficiency. It can be understood that the material for making nanoparticles can be metal or graphene; the shape of the nanoparticles can be spherical, ellipsoidal, or conical; the groove can be made by semiconductor technology, and then the Nanoparticles are placed in the grooves, and femtosecond lasers can also be used to directly produce arrays of nanoparticle dimer arrays. In a word, this embodiment does not limit the material, shape and production method of the nanoparticles.

The light energy collection microstructure includes a nanoparticle dimer array, and the nanoparticle dimer array is composed of periodically arranged nanoparticle dimers. Wherein, the arrangement direction of the nanoparticle dimers is perpendicular to the propagation direction of the incident light. The two nanoparticles in the nanoparticle dimer are distributed along the propagating direction of the incident light, and there is a dislocation in the polarization direction of the incident light. Under the irradiation of incident light, the two nanoparticles will be excited at the same time, forming electric dipole oscillation, generating localized surface plasmon resonance, and then coupling to promote the enhancement of surface plasmon resonance to achieve stable light energy. The continuous circulation can significantly improve the light energy collection efficiency. In addition, due to the improvement of light energy collection efficiency, there is no need to add a signal amplification function module at the back end, which can simplify the device structure, reduce the volume and production cost, and accelerate the miniaturization process of the device.

In one embodiment, please continue to refer to FIG. 1 , the first nanoparticles 110 and the second nanoparticles 120 are closely distributed in the incident light propagation direction k.

Specifically, as shown in FIG. 1 , the first nanoparticles and the second nanoparticles are closely distributed in the propagation direction of the incident light, which means that the common tangent L between the first nanoparticles 110 and the second nanoparticles 120 is perpendicular to the propagation direction of the incident light. z.

In the above embodiments, the first nanoparticles and the second nanoparticles are closely distributed in the direction of incident light propagation, which can reduce the difficulty of the process and further reduce the production cost.

In one embodiment, the radii of the first nanoparticles and the second nanoparticles are 10 nm-100 nm.

Specifically, the radii of the first nanoparticle and the second nanoparticle may be the same or different, as long as the radii are within the range of 10nm-100nm. For example, the first nanoparticles and/or the second nanoparticles may have a radius of 10 nm, 20 nm, 40 nm, 50 nm, 70 nm, 80 nm or 100 nm.

In the above embodiments, choosing an appropriate size as the radius of the nanoparticle can improve the effect of local surface plasmon resonance coupling and improve the light energy collection efficiency.

In one embodiment, the spacing between nanoparticle dimers is 370nm-1000nm.

As mentioned above, the nanoparticle dimers have a pitch of P _x in the x direction and a pitch of P _y in the y direction. Wherein, P _x and P _y may or may not be the same. Further, within the range of 370nm-1000nm, any value can be selected as the distance between nanoparticle dimers. For example, the pitch may be 370nm, 400nm, 500nm, 700nm, 850nm or 1000nm. Further, when the incident light is monochromatic light, a value equal to the wavelength of the incident light can be selected as the distance between nanoparticle dimers. For example, when the incident light wavelength is 532nm, 532nm can be selected as the distance between nanoparticle dimers.

In the above embodiments, choosing an appropriate size as the distance between nanoparticle dimers can improve the effect of local surface plasmon resonance coupling and improve the light energy collection efficiency. In one embodiment, please continue to refer to FIG. 1 , the misalignment distance between the first nanoparticle 110 and the second nanoparticle 120 in the incident light polarization direction E _is not more than half of the smaller spacing between nanoparticle dimers .

As mentioned above, the spacings P _x and P _y between nanoparticle dimers may not be equal in the two periodic alignment directions. When P _x and P _y are not equal, the dislocation distance S _x does not exceed half of the smaller value of P _x and P _y , which can avoid the mutual interference of two adjacent nanoparticle dimers, and is conducive to the formation of stable surfaces, etc. The ion polariton resonance further improves the light energy collection efficiency.

In one embodiment, the nanoparticle dimer is an inert metal nanoparticle dimer.

Specifically, an inert metal refers to a metal that cannot replace the hydrogen element in the hydride, that is, a metal that ranks after hydrogen in the periodic table of elements. Specifically, the inert metal material includes gold, silver, platinum and the like. Due to the excellent optical properties of inert metal materials, when the excitation light wavelength is in the visible light and part of the near-infrared region, localized surface plasmon resonance can be generated, and then the phenomenon of coupling surface plasmon resonance enhancement occurs, which can significantly improve Light energy harvesting efficiency.

In the above embodiments, the use of dimers of inert metal nanoparticles can increase the applicable wavelength range of the light energy harvesting microstructure, making the application scenarios of the device more flexible.

In one embodiment, the ratio of the radius of the nanoparticles in the nanoparticle dimers to the distance between the nanoparticle dimers is 1:10-1:7.

Specifically, after determining one of the parameters of the radius of the nanoparticle and the distance between the nanoparticle dimers, an arbitrary ratio can be selected within the range of 1:10-1:7, and then another one can be determined according to the ratio. parameter. For example, when the spacing P _x and P _y between nanoparticle dimers are both 532nm, when 1:10, 1:9, 1:8 and 1:7 are selected as the ratio of radius to lattice constant, the obtained The radii of the nanoparticles are 53.2 nm, 59.1 nm, 66.5 nm and 76 nm, respectively.

In the above embodiments, by limiting the ratio of the radius of the nanoparticles in the nanoparticle dimers to the distance between the nanoparticle dimers, the effect of local surface plasmon resonance coupling can be improved and the light energy collection efficiency can be improved.

In one embodiment, the material of the nanoparticles is silver, the radius of the nanoparticles is 90nm, the distance between dimers of the nanoparticles is 630nm, the dislocation in the horizontal direction is 120nm, and the wavelength range of the incident light is 500nm-800nm. The incident light propagates along the vertical k direction, and the polarization direction E coincides with the horizontal direction.

The incident planar light propagates along the vertical direction and irradiates the light energy harvesting microstructure, which will simultaneously excite multiple resonance modes. Figure 2 is the surface plasmon resonance absorption spectrum of this embodiment. Wherein, the abscissa is the wavelength, and the ordinate is the normalized absorbance. It can be seen from FIG. 2 that the light energy harvesting microstructure of this embodiment has three obvious resonant absorption peaks, corresponding to absorption wavelengths of 648nm, 665nm and 748nm.

FIG. 3 is a schematic diagram of the positive and negative charge distribution of the nanoparticle dimer in the resonance mode of this embodiment. It can be seen that the absorption peaks at 648nm, 665nm and 748nm correspond to the transverse resonance mode, local resonance mode and longitudinal resonance mode, respectively. The local resonance mode is consistent with the electric dipole oscillation of a single nanoparticle, and the plasmon coupling phenomenon does not occur between the two nanoparticles. The direction of the electric dipole moment in the transverse resonance mode is perpendicular to the polarization direction of the incident light, and the direction of the electric dipole moment in the longitudinal resonance mode is consistent with the polarization direction of the incident light. from excitonic coupling.

FIG. 4 is a schematic diagram of the spatial phase distribution and optical energy flow collection of the nanoparticle dimer in the three resonance modes of this embodiment. It can be seen intuitively from Figure 4 that there is an obvious phase reversal phenomenon in the transverse mode and the longitudinal mode, which indicates that the light energy around the nanoparticles will be directional modulated. In addition, it can be seen that the light energy flow around the nanoparticles is concentrated in the area near the surface of the metal nanoparticles in the form of a vortex, and stable light energy can be continuously circulated in both forward and reverse directions, so the loss of surface plasmon light energy is small.

In the above-mentioned embodiments, by selecting the appropriate spacing between nanoparticle dimers, the material, radius, and horizontal dislocation of the nanoparticles, the three resonance modes of the local surface plasmon laser can be realized, and the modulation of light energy and light The continuous circulation of energy is beneficial to reduce the loss of light energy and improve the efficiency of energy collection.

In one embodiment, there is provided a photosensitive element, the light energy collection microstructure described in any embodiment above.

Wherein, the photosensitive element refers to an element for collecting light signals. The photosensitive element may be a charge-coupled element, or a complementary metal-oxide-semiconductor device, or other types of devices. In this embodiment, the specific type of the photosensitive element is not limited. Specifically, the optical energy harvesting microstructure can be embedded in the photosensitive element, and it can be coordinated with other microstructures through optical and electrical connections to realize the collection and conversion of optical signals. The specific limitations of the light energy harvesting microstructure can be referred to above, and will not be repeated here.

In one embodiment, an optical device is provided, including the photosensitive element described in any of the above embodiments.

Among them, optical devices include but are not limited to nano-lasers, quantum storage computers, solar cells, and slow-down photoconductive communications. In a word, this embodiment does not limit the type of the optical device. The specific limitations of the photosensitive element can be referred to above, and will not be repeated here.

The technical features of the above embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be It is considered to be within the range described in this specification.

The above example only expresses several implementation modes of the present application, and the description thereof is relatively specific and detailed, but it should not be understood as limiting the scope of the patent for the invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of protection of the patent application should be based on the appended claims.

Claims (9)

1. A light energy collecting microstructure, comprising:

a nanoparticle dimer array composed of periodically arranged nanoparticle dimers; the arrangement direction of the nano particle dimers is vertical to the propagation direction of incident light; the first nanoparticles and the second nanoparticles in the nanoparticle dimer are distributed in a staggered manner in the propagation direction of the incident light, and the first nanoparticles and the second nanoparticles are distributed in a staggered manner in the polarization direction of the incident light;

under the excitation of the incident light, the first nano particle and the second nano particle are respectively excited to generate a first local surface plasmon resonance and a second local surface plasmon resonance; and the first local surface plasmon resonance and the second local surface plasmon resonance realize the enhancement of surface plasmon resonance through transverse coupling and longitudinal coupling.

2. The light energy collection microstructure of claim 1, wherein the first and second nanoparticles are misaligned in the polarization direction of the incident light by no more than half of the smaller spacing between the nanoparticle dimers.

3. The light energy collecting microstructure of claim 1, wherein the nanoparticle dimers have a spacing between 370nm and 1000nm.

4. The light energy collecting microstructure of claim 1, wherein the first and second nanoparticles are closely distributed in the incident light propagation direction.

5. The light energy collecting microstructure of claim 1, wherein the first and second nanoparticles have a radius of 10nm to 100nm.

6. The light energy collection microstructure of claim 1, wherein the nanoparticle dimers are inert metal nanoparticle dimers.

7. The light energy collection microstructure of any one of claims 1 to 6, wherein the ratio of the radius of the nanoparticles in the nanoparticle dimers to the spacing between the nanoparticle dimers is 1-1:7.

8. A photosensitive element comprising the light energy collecting microstructure according to any one of claims 1 to 7.

9. An optical device comprising the photosensitive element according to claim 8.

Images