Method for constructing film or array based on quantitative co-assembly of perovskite and metal particles

Abstract

The invention relates to the technical field of laser devices, in particular to a method for constructing a film or an array based on quantitative co-assembly of perovskite and metal particles, and the method comprises the following steps: 1) uniformly mixing the perovskite, the metal particles and polymethyl methacrylate in a dispersion solvent to prepare a mixed solution; 2) preparing a composite film from the mixed solution through a spin-coating method; or the mixed solution is used for constructing an array through a template method. Through the method, the influence of the surface plasma effect on the carrier dynamics can be deeply understood, and meanwhile, the enhancement effect of the plasma on the perovskite luminescence performance can be further explored.

Description

Technical Field

[0001] The present invention relates to the technical field of laser devices, and in particular, to a method for constructing a thin film or an array by quantitative co-assembly of perovskite and metal particles. Background Art

[0002] As a class of emerging and outstanding semiconductor materials, perovskite is revolutionizing the development of optoelectronics fields including solar cells, photodetectors, light-emitting diodes, and lasers. Since the improvement of radiative efficiency can bring about the enhancement of optoelectronic performance, suppressing non-radiative recombination and enhancing radiative recombination are crucial for constructing high-performance optoelectronic devices. So far, researchers have developed various strategies to reduce the non-radiative recombination efficiency of perovskite devices, such as reducing trap-induced non-radiative recombination through recrystallization and surface passivation in high-performance solar cells and light-emitting diodes. In contrast, enhancing radiative recombination is a more direct and effective strategy to improve the optoelectronic performance of perovskite in light-emitting applications. In this regard, researchers have adopted various strategies including quantum confinement, ion doping, surface modification, metamaterial research and development, and surface plasmon resonance to increase the radiative recombination rate of perovskite. It is worth noting that the surface plasmon of metal materials can generate strong local electromagnetic modes with high-density states, and thus can significantly accelerate the radiative recombination efficiency of perovskite. However, most perovskite-metal composites are planar structures composed of perovskite and metal thin films, where the enhancement of radiative recombination only occurs at the perovskite surface close to the metal. This two-dimensional spatial interaction reduces the degree of freedom in material design and makes it impossible to comprehensively understand how surface plasmons affect carrier dynamics, which greatly hinders the design and research and development of perovskite-metal composites with better luminescent properties.

[0003] Currently, there are few reports on the system for three-dimensional and quantitative regulation of radiative efficiency in perovskite-metal materials and their laser devices. Therefore, the present invention is proposed. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a method for constructing a thin film or a laser array by quantitative co-assembly of perovskite and metal particles. Through this method, not only can the influence of surface plasmon effects on carrier dynamics be deeply understood, but also the enhancement effect of plasmons on the luminescent properties of perovskite can be further explored, which can be used for the construction of high-performance laser arrays and the regulation of their radiative recombination efficiency.

[0005] To achieve the above object, the technical solution of the present invention is as follows:

[0006] A method for constructing a thin film or an array by quantitative co-assembly of perovskite and metal particles, the method comprising:

[0007] 1) Mix perovskite, metal particles, and polymethyl methacrylate evenly in a dispersion solvent to form a mixed solution;

[0008] 2) Prepare a composite film from the mixed solution by spin coating; or, construct an array from the mixed solution by the template method.

[0009] The high-performance laser array constructed based on the quantitative co-assembly of perovskite and metal particles involved in the present invention includes the quantitative assembly of a perovskite and metal particle composite film and the construction of a laser array.

[0010] Mix perovskite, a quantitative amount of metal particles, and a trace amount of polymethyl methacrylate (PMMA) evenly in a dispersion solvent to form a mixed solution;

[0011] The perovskite includes its precursor solution or perovskite micro-nano crystals. The perovskite can be an all-inorganic perovskite or an organic-inorganic hybrid perovskite, both of which are conventional perovskite materials for preparing thin films or laser devices in the art; the size of the perovskite in the present invention can be on the nanoscale, and specifically can preferably be 7-11 nm.

[0012] The metal particles include gold particles or silver particles having surface plasmon resonance, etc.; those skilled in the art can also select other metal ions having surface plasmon resonance according to needs, preferably nano metal ions, such as gold nano ions or silver nano ions. The specific size can be about 1-20 nm.

[0013] The dispersion solvent is a solvent capable of dispersing perovskite precursors or perovskite nano crystals, such as N,N-dimethylformamide, toluene, n-hexane, etc.

[0014] The composite film is prepared by spin coating the mixed solvent evenly on a quartz glass substrate and drying. The contents of the metal particles and PMMA are 0-1 wt% and 0-5 wt% of the perovskite respectively; the rotation speed during spin coating will affect the thickness of the film, and the rotation speed used in the present invention is 500-20000 revolutions per minute.

[0015] The laser array is constructed by the template method. The specific steps are as follows: Drop the above-mentioned mixed solution onto a planar template with a raised pattern. Subsequently, cover a quartz substrate on the solution to form a multi-layer system of template - mixed solution - quartz substrate, and apply a certain pressure and temperature to the multi-layer system. The solution is assembled along the raised pattern of the template under the drive of capillary force. After the solution has completely evaporated, the laser array can be obtained. Preferably, the planar template with a raised pattern can be a cylindrical raised pattern arranged in an array. Those skilled in the art can also select planar templates with other specific patterns according to needs, which can include circles, squares, rectangles, rings, long lines, etc.; the circular raised pattern can be a single cylindrical shape or several cylindrical shapes arranged in an array; the square raised pattern can be a single square column shape or several square column shapes arranged in an array; the rectangular raised pattern can be a single rectangular column or several rectangular columns arranged in an array; the circular ring-shaped raised pattern can be a single ring-shaped column or several ring-shaped columns arranged in an array. And so on.

[0016] The temperature applied to the multi-layer system is 10 - 80 °C.

[0017] The concentration of the mixed solution affects the morphology of the assembled array. If it is too low, the assembled pattern will lose the shape of the template; if it is too high, the boundary of the assembled morphology will be unclear. Generally, the applicable concentration of perovskite in the dispersing solvent is 20 - 100 mg / mL.

[0018] The present invention prepares a co-assembled film of perovskite and metal particles through a simple spin-coating process. In the co-assembled film, the metal particle body can provide three-dimensional local surface plasmon resonance, so it can accelerate the radiative recombination process of adjacent perovskite.

[0019] The present invention further constructs perovskite composite films with different metal contents by quantitatively introducing metal particles. By detecting the photophysical properties of these composite films, the evolution of the radiative and non-radiative recombination processes in perovskite under the plasmon mode is revealed. This can not only help us comprehensively understand the influence of surface plasmons on perovskite carrier dynamics, but also determine that the optimal concentration of the metal particle body required to achieve the highest radiative efficiency of perovskite is 0.25%. This accelerated radiative recombination process will improve the optical gain performance of perovskite. Therefore, by co-assembling perovskite and metal particles, a low-threshold laser array (14.4 μJ / cm 2 ) can be constructed.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. In the present invention, perovskite and metal particles can be assembled into a composite film. The metal particle body can provide three-dimensional local surface plasmon resonance. Therefore, the radiative recombination process of adjacent perovskite can be quantitatively accelerated by introducing different amounts of metal particles. Compared with the pure perovskite film, its highest luminescence intensity can be increased by 37.5 times.

[0022] 2. Since the introduction of metal particles can promote the radiative recombination process of perovskite through the Purcell effect, the optical gain performance of perovskite is improved. Therefore, by co-assembling perovskite and metal particles, a low-threshold laser array can be constructed. These results further deepen the understanding of carrier dynamics involving plasmons and pave the way for designing perovskite-metal systems with high-performance optoelectronic properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a planar template with a cylindrical protrusion pattern;

[0024] Figure 2 is a transmission electron microscope image of the perovskite particles used in Example 1;

[0025] Figure 3 is a transmission electron microscope image of the metal particles used in Example 1;

[0026] Figure 4 is a scanning electron microscope image of the film prepared in Example 1;

[0027] Figure 5 is the intensity change of the emission spectra of the hybrid film and the comparative film prepared in Example 2;

[0028] Figure 6 is a scanning electron microscope image of the one-dimensional long-line laser array prepared in Example 3;

[0029] Figure 7 is a microscope image of the laser array prepared in Example 4;

[0030] Figure 8 is the laser spectrum and its threshold curve of the disks in the array assembled in Example 4. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The technical solutions of the present invention will be described in detail below with reference to the drawings and embodiments.

[0032] Example 1

[0033] The CsPbBr3 perovskite particles, 1 wt% gold nanoparticles, and 2 wt% polymethyl methacrylate (PMMA) were mixed uniformly in toluene solvent to form a mixed solution, which was spin-coated on a quartz substrate at a speed of 8000 revolutions per minute. After the solvent dried, a mixed thin film was obtained.

[0034] The transmission electron microscope images of the perovskite particles and metal particles used in this example are as Figure 2 and Figure 3 shown. The scanning electron microscope image of the thin film prepared in this example is as Figure 4 shown. As Figure 2 shown, the size range of the perovskite particles used is 7 - 11 nm, and the size of the gold nanoparticles used in this example is about 9 nm ( Figure 3 ). Both of the above two kinds of particles have good dispersibility. The surface of the mixed thin film prepared from them is flat, as Figure 4 shown.

[0035] Example 2

[0036] The CsPbBr3 perovskite particles, different contents of gold nanoparticles (0 - 0.25 wt%), and 2 wt% polymethyl methacrylate (PMMA) were mixed uniformly in n - hexane solvent to form a mixed solution, which was spin-coated on a quartz substrate at a speed of 4000 revolutions per minute. After the solvent dried, a mixed thin film containing different amounts of metal was obtained.

[0037] The intensity change of the emission spectra of the mixed thin film and the comparative thin film prepared in this example is as Figure 5 shown. Its emission intensity changes with the increase of the amount of metal particles introduced. When the content of gold nanoparticles is 0.25 wt% of the perovskite, its emission intensity is increased by up to 37.5 times.

[0038] Example 3

[0039] The CsPbBr3 perovskite precursor, gold nanoparticles, and PMMA were mixed uniformly in toluene solvent to form a mixed solution. The mixed solution was dropped onto a planar template with a raised long - line pattern, and then a quartz substrate was covered on the solution to form a multi - layer system of template - mixed solution - quartz substrate. A certain pressure was applied to the multi - layer system and it was placed in an oven at 20 °C until the solution evaporated completely to obtain a one - dimensional long - line laser array.

[0040] The scanning electron microscope image of the one - dimensional long - line laser array prepared in this example is as Figure 6 shown. The structure of the obtained array is coherent and the boundary is clear.

[0041] Example 4

[0042] Mix CsPbBr3 perovskite particles, gold nanoparticles and PMMA evenly in a solvent to form a mixed solution. Drop the mixed solution onto a planar template with raised circular patterns (such as Figure 1 shown). Subsequently, cover a quartz substrate on top of the solution to form a multi-layer system of template - mixed solution - quartz substrate. Apply a certain pressure to the multi-layer system and place it in an oven at 20 °C until the solution has completely evaporated to obtain a disk laser array.

[0043] The microscope image of the laser array prepared in this example is as shown in Figure 7 shown. The laser spectra and threshold curves of the disks in the assembled array are as shown in Figure 8 shown. At low excitation intensities, the luminescence of the sample is mainly spontaneous emission. When the excitation intensity exceeds 14.4 μJ / cm 2 , the luminescence peak suddenly becomes narrower (<1 nm). Figure 8 As shown in the figure of the change of its luminescence intensity with the excitation intensity, it can be seen that at this time the sample luminescence is stimulated emission and laser emission occurs.

[0044] Comparative Example 1

[0045] Similar to Example 2, when adding more than 1% of gold nanoparticles, the luminescence of the finally obtained thin film is not enhanced.

[0046] Comparative Example 2

[0047] Similar to Example 3, the mixed solution was not dropped onto the template but onto ordinary quartz glass, and finally a laser array was not obtained.

[0048] Comparative Example 3

[0049] Mix CsPbBr3 perovskite particles, gold nanoparticles and PMMA in an aqueous solution to form a mixed solution. Drop the mixed solution onto a planar template with raised circular patterns. Subsequently, cover a quartz substrate on top of the solution to form a multi-layer system of template - mixed solution - quartz substrate. Apply a certain pressure to the multi-layer system and place it in an oven at 20 °C to evaporate the solution. Since perovskite is an ionic crystal and is unstable and easily decomposes in water, and at the same time metal particles and PMMA cannot be evenly dispersed in the aqueous solution, the final laser array was not successfully constructed.

[0050] The upper and lower limits and interval values of the process parameters (such as temperature, time, etc.) of the present invention can all implement this method, and the examples are not listed one by one here.

[0051] The content not detailed in the present invention can all adopt the conventional technical knowledge in the field.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the embodiments, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles, the method comprising: 1) mixing perovskite, metal particles and polymethyl methacrylate in a dispersing solvent to form a mixed solution; 2) The mixed solution is used to prepare a composite film by spin coating; or, the mixed solution is used to construct an array by a template method.

2. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 1, characterized in that: The contents of the metal particles and polymethyl methacrylate are 0-1 wt % and 0-5 wt % of the perovskite, respectively.

3. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 1, characterized in that: The perovskite is a perovskite precursor solution or a perovskite micro-nano crystal; the perovskite is an all-inorganic perovskite or an organic-inorganic hybrid perovskite.

4. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 1, characterized in that: The metal particles are gold nanoparticles or silver nanoparticles.

5. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 1, characterized in that: The dispersion solvent is N,N-dimethylformamide, toluene or n-hexane.

6. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 1, characterized in that: The mixed solution is used to prepare the composite film by spin coating as follows: The mixed solvent is evenly distributed on a quartz glass substrate or a sapphire substrate by a spin coating method, and a composite film is obtained by drying under vacuum conditions.

7. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 6, characterized in that: The rotation speed of the spin coating is 500-20000 rpm.

8. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 1, characterized in that: The mixed solution is used to construct the array by the template method as follows: The mixed solution is dropped onto a flat template with a raised pattern, and then a quartz glass substrate or a sapphire substrate is covered on the mixed solution to form a multilayer system of flat template-mixed solution-quartz substrate. Pressure and temperature are applied to the multilayer system so that the mixed solution is assembled along the raised pattern of the flat template under the drive of capillary force. After the solution evaporates, an array can be obtained.

9. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 8, characterized in that: The raised patterns on the planar template include cylindrical, circular, square, rectangular, circular ring or long lines arranged in an array.

10. The method for constructing a thin film or array based on quantitative co-assembly of perovskite and metal particles according to claim 8, characterized in that: The multilayer system applies pressure and temperature, which is 10-80°C.

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