CN116073219B - A preparation method of an all-inorganic perovskite liquid laser based on a microfluidic channel - Google Patents

Abstract

The invention provides a preparation method of an all-inorganic perovskite liquid laser based on a microfluidic channel, belonging to the technical field of photoelectric information and comprisingThe method comprises the following steps: all-inorganic halogen perovskite CsPbBr for preparing dodecylbenzene sulfonic acid ligand by using hot injection method ₃ Quantum dot dispersion; a U-shaped flow channel is carved on the PMMA substrate by utilizing a micro control system; ultrasonic cleaning, drying and N-bonding the substrate and the bonding plate ₂ 0, plasma treatment; processing the optical fiber; placing the fiber cores into the flow channels, and carrying out vacuum hot-pressing packaging on the bonding plate substrate; and (3) taking the bonding steel needle as a runner inlet and outlet, and injecting the quantum dot dispersion liquid into the micro-flow channel. The prepared perovskite liquid laser realizes whispering gallery mode laser. The method provided by the invention is simple and efficient to operate, realizes excellent laser performance, and effectively makes up the short plates with high laser threshold value, multiple laser angle modes and low working stability under high power of the liquid laser in the prior art in the field of optical communication.

Description

A preparation method of an all-inorganic perovskite liquid laser based on a microfluidic channel

technical field

The invention belongs to the field of optoelectronic information technology, and in particular relates to a preparation method of an all-inorganic perovskite liquid laser based on a microfluidic channel.

Background technique

Optofluidic lasers are an emerging technology that integrates microcavities, microfluidic channels, and liquid gain media. It has broad applications in novel photonic devices, such as on-chip tunable coherent light sources and lasers for biological control and sensitive analysis of biomolecules. Photonic devices based on semiconducting colloidal quantum dots (QDs) have attracted considerable attention due to their ease of processing, spectral tunability over a wide wavelength range, and potentially low temperature-insensitive lasing threshold.

Compared with solid-state lasers that are tightly stacked with gain materials, liquid lasers exhibit unique characteristics: due to the combination of microfluidic technology and photonics, it provides a new solution for the development of highly integrated micro-optical devices, in optoelectronic information communication , Optical encryption, laser detectors, and other optoelectronic information applications have great potential.

Liquid phase gain medium is a key component of liquid lasers, and its iteration is crucial to the development of optofluidic technology. Initially, fluorescent dyes have been extensively studied as liquid gain media. In these dye liquid lasers, complex pumping and operating configurations are required to overcome the irreversible conversion of the dye gain medium to non-fluorescent molecules in the resting state. Even so, dye molecules are gradually photodegraded during photoexcitation, resulting in lower gain efficiency and requiring periodic solution replacement. In recent years, several reports have investigated the possibility of using CdSe-based quantum dots as liquid laser gain media, however, due to the relatively low gain coefficient, the pumping threshold of these devices is too high for practical applications. Therefore, it is necessary to seek new liquid phase gain media for the development of high-performance liquid lasers.

Inorganic lead halide perovskite nanocrystals are a new class of laser materials emerging in recent years. Compared with conventional CdSe-based NCs, inorganic lead halide perovskite nanocrystals have larger gain coefficients and higher defect tolerance, which makes inorganic lead halide perovskite nanocrystals a potential liquid gain medium. However, despite significant progress in the development of solid-state lasers based on inorganic lead halide perovskite nanocrystals in the past few years, liquid lasers based on inorganic lead halide perovskite nanocrystals have been delayed.

In 2014, the research proposed an ideal optofluidic laser with monolayer gain, but due to the technical limitations of the semiconductor era at that time, no excellent technical results were achieved. However, the proposed solid-liquid hybrid laser model can realize high-quality corridor-type lasers, and proposes new possibilities for fluidic technology. Nowadays, when perovskite is introduced as a new type of semiconductor, perovskite materials with high gain, high reabsorption coefficient, and long carrier lifetime can better fit the shape model, and liquid lasers with higher than expected effects can be prepared. In 2019, it was found that the use of dodecylbenzenesulfonic acid as a ligand material for the preparation of perovskite quantum dots can improve the storage time of the material and improve the luminescent performance of the material.

Contents of the invention

In order to solve the defects of the prior art, the invention provides a preparation method of an all-inorganic perovskite liquid laser based on a microfluidic channel.

The present invention solves the problems of high laser threshold, large number of laser modes, and low working stability under high power in the prior art, and the specific technical solution includes the following steps:

A method for preparing an all-inorganic perovskite liquid laser based on a microfluidic channel, comprising the following steps:

Step 1: preparing the all-inorganic halogen perovskite CsPbBr ₃ quantum dot dispersion of dodecylbenzenesulfonic acid ligand;

Step 2: Engraving a U-shaped flow channel on the PMMA substrate;

Step 3: Ultrasonic cleaning, drying and N ₂ 0 plasma treatment of the substrate and bonding plate;

Step 4: Place the SiO ₂ fiber core in the flow channel, and vacuum heat-press the substrate with a bonding plate to make a chip with a microfluidic channel;

Step 5: Bond steel needles on the microfluidic channel as the inlet and outlet of the flow channel, and inject the quantum dot dispersion liquid into the microfluidic channel to prepare a perovskite liquid laser to realize the whispering gallery mode laser.

Further, the concentration of the all-inorganic halogen perovskite CsPbBr ₃ quantum dot dispersion is not lower than 133.0 mg·mL ^-1 .

Further, the cross-sectional size of the U-shaped flow channel is not greater than 250*250 µm ² .

Further, the step 3 is specifically, the substrate and the bonded plate are ultrasonically cleaned with deionized water at 50 ° C for 3 times, each time for 15 minutes; then dried in a vacuum oven at 80 ° C for 30 minutes; and finally using Plasma equipment N ₂ 0 The gas treatment was 180 seconds, the gas flow rate was 60 sccm, the vacuum pressure was 30 mTorr, and the plasma power was 170 W.

Further, the SiO ₂ core is a SiO _{2 core with a smooth surface obtained by removing the cladding layer from the SiO 2 optical} fiber and then using a flame drawing method.

Further, the heating rate of the vacuum hot-press package is 9°C/min, the hot-pressing temperature is 117°C, the hot-pressing time is 33 seconds, the cooling rate is 5°C/min, and the temperature drops to 67°C and taken out.

Further, the all-inorganic halogen perovskite is a rectangular single crystal.

Further, the SiO ₂ core has a radius of 12 µm to 44 µm.

Compared with the prior art, 1. The method provided by the present invention is simple and efficient in operation, and is easy to implement with simple equipment; 2. The present invention prepares a liquid laser, which effectively compensates for the high laser threshold of the liquid laser in the prior art, Short board with low working stability under high power.

Description of drawings

FIG. 1 is a schematic flow diagram of the present invention using a micro-control system to prepare a microfluidic chip on a PMMA substrate.

Fig. 2 is a photo of a microfluidic chip injected with a _CsPbBr3 quantum dot dispersion liquid of dodecylbenzenesulfonic acid (DBSA) ligand in the present invention.

Fig. 3 is a photo of the prepared liquid laser excited by femtosecond laser in the present invention.

Fig. 4 is the laser spectrum excited by the femtosecond laser of the present invention and the laser threshold characterization of the present invention under pumping conditions.

Fig. 5 is the laser threshold characterization under the pumping condition of the present invention, showing that the invention realizes lasing when the pumping is 22.7µJ·cm ^-2 .

Fig. 6 is the spectrum obtained by replacing the optical fibers of different sizes in the microfluidic chip according to the present invention, and the corresponding changes in the free spectral range and the number of laser modes are marked in the figure. When the fiber radius is 44μm, the free spectral radius is 0.67nm. When the fiber radius is 16μm, the free spectral radius is 1.83nm. When the fiber radius is 12μm, the free spectral radius is 2.44nm.

Fig. 7 is a graph showing the variation of luminous intensity obtained by exciting the liquid laser prepared by the femtosecond laser with the same power and the common solid thin-film fiber laser according to the present invention. The upper curve is the normalized luminous intensity of the liquid laser, and the lower curve is the normalized luminous intensity of the solid-state laser.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment, further illustrate the present invention, should be understood that these embodiments are only for illustrating the present invention and are not intended to limit the scope of the present invention, after having read the present invention, those skilled in the art will understand various aspects of the present invention Modifications in equivalent forms all fall within the scope defined by the appended claims of this application.

As shown in Figure 1, an all-inorganic perovskite liquid laser based on microfluidic channels is prepared by the following method:

Step 1: preparing the all-inorganic halogen perovskite CsPbBr ₃ quantum dot dispersion of dodecylbenzenesulfonic acid ligand;

Step 2: Engraving a U-shaped flow channel on the PMMA substrate;

Step 3: Ultrasonic cleaning, drying and N ₂ 0 plasma treatment of the substrate and bonding plate;

Step 4: Place the SiO ₂ fiber core in the flow channel, and vacuum heat-press the substrate with a bonding plate to make a chip with a microfluidic channel;

Step 5: Bond steel needles on the microfluidic channel as the inlet and outlet of the flow channel, and inject the quantum dot dispersion liquid into the microfluidic channel to prepare a perovskite liquid laser to realize the whispering gallery mode laser.

Use a micro-control system (LSmicro2020 CNC) to prepare a microfluidic chip on a PMMA substrate, install a milling cutter of a suitable size, set the z-axis cutting distance, which is the engraving depth, and then set the x, y-axis to engrave a sample of a suitable size, as shown in the figure 2. The cross-sectional size of the U-shaped flow channel is not greater than 250*250 µm ² .

Preparation of all-inorganic halogen perovskite CsPbBr ₃ quantum dot dispersion liquid of dodecylbenzenesulfonic acid (DBSA) ligand by hot injection method, said all-inorganic halogen perovskite is a rectangular single crystal; said hot injection method As follows: Cs ₂ CO ₃ (0.0593 g, 0.182 mmol), Pb(OAc) ₂ (0.206 g, 0.54 mmol) ODE (10ml) and dodecylbenzenesulfonic acid (1.2045g, 3.689mmoL) were injected into 100mL three-neck flask, and degas the mixture at 120 °C for half an hour under a stream of argon. The clear solution was kept below 120 °C for another 30 min, and then a toluene solution (748 mg, 1.37 mmol, 2 mL) predissolved tetraoctylammonium bromide was rapidly injected into the above precursor solution. After 5 s, the reaction mixture was cooled in a water bath.

Substrates and bonded plates were ultrasonically cleaned with deionized water at 50 °C for 3 times, each time for 15 minutes; then dried in a vacuum oven at 80 °C for 30 minutes; after drying, they were treated with N ₂ 0 gas for 180 seconds in a Plasma device with a gas flow rate of 60 sccm , vacuum pressure 30 mTorr, plasma power 170 W. During the vacuum hot pressing process, the heating rate was 9 ℃/min, the hot pressing temperature was 117 ℃, the hot pressing time was 33 seconds, the cooling rate was 5 ℃/min, and the temperature dropped to 67 ℃ for removal.

The SiO ₂ core is a SiO ₂ core with a smooth surface obtained by removing the cladding from the SiO ₂ optical fiber by flame drawing.

The CsPbBr ₃ quantum dot dispersion liquid of dodecylbenzenesulfonic acid (DBSA) ligand was injected into the microfluidic chip, and the smooth optical microfluidic core in the microfluidic chip was used as a whispering gallery mode microcavity, and the femtosecond laser was used to Excite the prepared liquid laser, as shown in Figure 3.

Through the micro-area fluorescence test system built by the laboratory, the laser performance was characterized under pumping conditions, and multiple luminescence peaks appeared at a certain pumping intensity, and the luminous intensity of the present invention continued to increase as the pumping intensity increased, as shown in Figure 4 shows.

Through the micro-area fluorescence test system built by the laboratory, the laser performance was characterized under pumping conditions, and it was found that the luminous intensity of the microfluidic chip was significantly improved under the condition of pumping at 22.7µJ cm ^-2 , which proved that the microfluidic chip realized Laser, as shown in Figure 5.

The spectra in Figure 6 are obtained by replacing the optical fibers of different sizes in the microfluidic chip. The corresponding changes in the free spectral range and the number of angular modes are marked in the figure. When the optical fiber radius is 44 μm, the free spectral radius is 0.67 nm. When changing the fiber radius to 16μm, the free spectral radius is 1.83nm. When changing the fiber radius to 12μm, the free spectral radius is 2.44nm.

The luminous intensity change diagram in Figure 7 is obtained by exciting the prepared liquid laser and the common solid thin-film fiber laser with the same power femtosecond laser. Two optical fibers of the same size were used as the resonant cavity of the liquid laser and the solid thin film laser respectively, and the excitation was continued at room temperature for more than 4 hours (corresponding to about 1.4 × 10 ⁷ laser irradiations). For the liquid laser, no significant laser intensity drop was observed throughout the measurement. However, the lasing intensity of the thin-film-based solid-state laser dropped sharply at about 30 minutes, and then gradually decreased to about 56% of the initial intensity.

The realized liquid laser has a line width of 0.069nm, a quality factor of 7480, a laser threshold as low as 22.7µJ·cm ^-2 , and can maintain a stable output power under the excitation light of not less than 173.1 µJ·cm ^-2 . hours, is a high-quality liquid laser.

Optical performance characterization:

The fluorescence spectrum of the above-mentioned CsPbBr ₃ microfluidic channel chip was characterized by a micro-area fluorescence test system built in the laboratory. This micro-area spectrum test system was built based on the spectrometer iHR320 produced by Horiba Company, and an externally connected microscope (RX50M) was used for sample positioning. The excitation light wavelength The wavelength is 405 nm, and the spot size is about 10 μm.

Claims (3)

1. A preparation method of an all-inorganic perovskite liquid laser based on a microfluidic channel is characterized by comprising the following steps: the method comprises the following steps:

step 1: all-inorganic halogen perovskite CsPbBr for preparing dodecylbenzenesulfonic acid ligand ₃ Quantum dot dispersion liquid, all-inorganic halogen perovskite CsPbBr ₃ The concentration of the quantum dot dispersion liquid is not lower than 133.0 mg mL ^-1 The all-inorganic halogen perovskite is a rectangular single crystal;

step 2: a U-shaped runner is carved on a PMMA substrate, and the cross section size of the U-shaped runner is not more than 250 mu m ² ；

Step 3: ultrasonically cleaning the substrate and bonding plate with deionized water at 50deg.C for 3 times eachSecondary 15 minutes; drying in a vacuum drying oven at 80 ℃ for 30 minutes; post-utilization Plasma device N ₂ 0 gas treatment for 180 seconds, gas flow rate of 60 sscm, vacuum pressure of 30 mTorr, and plasma power of 170W;

step 4: siO is made of ₂ Placing fiber cores into the flow channels, vacuum thermocompression packaging the substrate with bonding plate to obtain chip with microfluidic channels, and performing vacuum thermocompression packaging on the substrate with bonding plate to obtain SiO ₂ The radius of the fiber core is 12 mu m-44 mu m;

step 5: and bonding a steel needle on the microfluidic channel as a runner inlet and outlet, and injecting quantum dot dispersion liquid into the microfluidic channel to prepare a perovskite liquid laser, so as to realize whispering gallery mode laser.

2. The method for preparing the micro-fluidic channel-based all-inorganic perovskite liquid laser is characterized in that: the SiO is ₂ The fiber core is made of SiO ₂ After the coating layer is removed from the optical fiber, a flame stretching method is used for preparing SiO with smooth surface ₂ A core.

3. The method for preparing the micro-fluidic channel-based all-inorganic perovskite liquid laser is characterized in that: the heating rate of the vacuum hot-pressing package is 9 ℃/min, the hot-pressing temperature is 117 ℃, the hot-pressing time is 33 seconds, the cooling rate is 5 ℃/min, and the temperature is reduced to 67 ℃ and taken out.

Images