WO2019200876A1

WO2019200876A1 - Micro-reaction device and method for efficiently preparing blue light perovskite quantum dots by means of low temperature method

Info

Publication number: WO2019200876A1
Application number: PCT/CN2018/111937
Authority: WO
Inventors: 李宗涛; 汤勇; 余彬海; 卢汉光; 饶龙石; 宋存江; 陆龙生
Original assignee: 华南理工大学
Priority date: 2018-04-17
Filing date: 2018-10-25
Publication date: 2019-10-24
Also published as: CN108393049A

Abstract

A micro-reaction device for efficiently preparing blue light perovskite quantum dots by means of a low temperature method, comprising a syringe pump (10), a reactor (11) and a temperature control module (12); the temperature control module (12) comprises a temperature controller (13), a water cooling head (14) and a constant temperature water tank (15); the reactor (11) comprises an upper cover plate (8) and a micro-channel (9), the micro-channel (9) being fixed below the upper cover plate (8); the syringe pump (10) is disposed above the reactor (11), the temperature controller (13) is installed at the center of a surface of the upper cover plate (8) and is electrically connected to the micro-channel (9), the water cooling head (14) is closely attached to a lower surface of the micro-channel (9), and a layer of thermally conductive silicone grease is coated on a contact surface, the water cooling head (14) and the constant temperature water tank (15) being connected by means of a water pipe; an upper surface of the micro-channel (9) is provided with an inlet passage, a first passage, a second passage, a third passage and a fourth passage, which communicate in sequence. A micro-reaction method for efficiently preparing blue light perovskite quantum dots by means of a low temperature method, which employs a micro-reaction device for efficiently preparing blue-bit perovskite quantum dots by means of a low temperature method. The device and method have the advantages of having a good mixing effect, a high degree of integration, high preparation efficiency, and so on, and relate to the technical field of photoelectric material preparation.

Description

Micro-reaction device and method for efficiently preparing blue light perovskite quantum dots by low temperature method

Technical field

The invention belongs to the technical field of photoelectric material preparation, and particularly relates to a micro-reaction device and a method for efficiently preparing a blue light perovskite quantum dot by a low temperature method.

Background technique

LED lighting and display products have been widely concerned by the society since their birth because of their high luminous efficiency, energy saving, good color rendering and long life. Most of the LED products on the market now use the structure of the PN junction. The products using the structure of the PN junction have the disadvantages of wide emission peak and low fluorescence efficiency, resulting in low luminous efficiency index of LED products, and have not yet reached people. The expected effect. The halide perovskite quantum dots, which have been gradually developed in recent years, have the advantages of narrow emission peak, fluorescence efficiency up to 90%, and adjustable emission wavelength. The QLED devices prepared on the basis of these can better improve color temperature and light. The properties of pass, light effect, etc. have great application value. However, the current perovskite quantum dot preparation technology is still very immature, especially the blue-doped perovskite quantum dots are far less than the green-light perovskite in terms of fluorescence quantum efficiency due to the combination of Cl ions and matrix. Quantum dots; in addition, the existing preparation method adopts a conventional reaction device, the efficiency is too low, and it is difficult to prepare a large number of perovskite quantum dots at one time, and it is important to find a continuous and efficient method for preparing blue-crystal perovskite quantum dots. research value.

Summary of the invention

In view of the above problems, the present invention provides a microreactor for efficiently preparing a blue light perovskite quantum dot by a low temperature method, which has the advantages of good mixing effect, high integration, high preparation efficiency, and the fluorescence efficiency of the prepared blue light perovskite quantum dot. High, wavelength regulation is continuous and accurate.

Another object of the present invention is to provide a microreaction method for efficiently preparing a blue light perovskite quantum dot by a low temperature method.

A micro-reaction device for efficiently preparing blue-light perovskite quantum dots by low-temperature method, which comprises: a syringe pump, a reactor and a temperature control module;

The temperature control module includes a temperature controller, a water cooling head, and a constant temperature water tank;

The reactor comprises an upper cover and a microchannel, and the microchannel is fixed below the upper cover;

The injection pump is arranged above the reactor, the temperature controller is installed in the center of the surface of the upper cover plate and is electrically connected with the microchannel, the water cooling head is closely attached to the lower surface of the microchannel, and is applied on the contact surface of the water cooling head and the microchannel. There is a layer of thermal grease, and the water-cooled head is connected to the constant temperature water tank through a water pipe;

The upper surface of the microchannel is provided with an entrance channel, a first channel, a second channel, a third channel and a fourth channel which are sequentially connected, and the first channel, the second channel, the third channel and the fourth channel are a set of buckles The microchannels of the type are connected by pipelines, and each group of the buckle type microchannels comprises a plurality of annular microchannels connected in sequence, and the annular microchannels are connected by a loop, on the access road. A first inlet and a second inlet are provided, a third inlet is provided at the junction of the second passage and the third passage, and a product outlet is provided at the end of the fourth passage.

Preferably, each set of ring-type microchannels comprises four annular microchannels connected in sequence, the circular microchannels are misaligned microchannels, one ring is a narrow channel, and the other ring is a wide channel, a wide type The misalignment distance between the channel and the narrow channel is 0.4mm-0.6mm, the wide channel has a circular arc shape, and the wide channel has an arc of 90°-150°.

Preferably, the narrow channel has a diameter of 0.4 mm to 0.6 mm, and the wide channel has a diameter of 0.9 mm to 1.2 mm.

Preferably, the entrance channel comprises a main entrance, a first entrance and a second entrance, the first entrance and the second entrance are merged into the main entrance, the main entrance and the first passage are connected; the first entrance is provided with a first entrance, and the second The second inlet is provided on the entrance; the diameter of the pipeline between the first passage, the second passage, the third passage and the fourth passage is 1.5 mm-2 mm.

Preferably, the microchannel is made of a semiconductor refrigerating sheet, and the channel is processed on the cold surface of the semiconductor refrigerating sheet, and a layer of boron nitride is sprayed.

The upper cover is made of aluminum alloy.

A microreaction method for efficiently preparing blue light perovskite quantum dots by low temperature method, and using the above low temperature method to efficiently prepare a microreactor for blue light perovskite quantum dots, comprising the following steps:

(1) Device assembly: a microreactor device for efficiently preparing a blue light perovskite quantum dot by a low temperature method;

(2) configuration mixed solution: the amount of oleylamine and oleic acid, placed in DMF solvent, stirred at 900-1200r / min, the volume ratio of DMF solvent, oleic acid, oleylamine is 20:2:1;

(3) Equipped with DMF-PbBr ₂ solution and DMF-CsBr solution: PbBr ₂ solid and CsBr solid were weighed on an electronic balance, and the molar ratio of PbBr ₂ solid to CsBr solid was 2:1, and added to two portions respectively. The mixed solution disposed in the step (2) is further stirred at a speed of 900-1200 r/min to obtain a DMF-PbBr ₂ solution and a DMF-CsBr solution, respectively;

(4) Set the temperature control module: open the switch of the constant temperature water tank and the temperature controller, the water temperature of the constant temperature water tank is set to 5 °C -10 °C, the water flow rate of the constant temperature water tank is set to 1.5L/min-2.5L/min, the temperature controller The target temperature value is set to -50 ° C - 0 ° C;

(5) conveying raw materials: when the actual temperature reaches the set target temperature value, the DMF-PbBr ₂ solution and the DMF-CsBr solution are respectively introduced from the first inlet and the second inlet at a uniform rate, from the third inlet at a uniform rate. Passing in toluene;

(6) Product collection: The generated blue light perovskite quantum dots were collected at the product outlet.

Preferably, the rate at which the first inlet is passed into the DMF-PbBr ₂ solution and the rate at which the second inlet is passed into the DMF-CsBr solution are both 0.5 mL/min to 1.5 mL/min, and the rate at which the third inlet is introduced into the toluene is 5- 10 mL/min.

Preferably, the concentration of the DMF-PbBr ₂ solution and the DMF-CsBr solution are both 0.2 mmoL/mL-0.4 mmoL/mL.

Preferably, in the step (2), oleylamine is 1 mL, oleic acid is 0.5 mL, and DMF solvent is 10 mL.

Preferably, 0.147 g of PbBr ₂ solids and 0.043 g of CsBr solids are weighed.

Advantages of the invention:

1. In the present invention, the microchannel has high integration degree and the size of each channel is small, and the Peltier effect of the semiconductor refrigeration sheet is used to obtain a better cooling effect, based on the raw materials PbBr ₂ and CsBr of the green perovskite quantum dots. By controlling the temperature to control the particle size of the perovskite quantum dots, the principle of supersaturated crystallization is used to efficiently synthesize the blue light perovskite quantum dots, the mixing effect is good, the integration degree is high, and the preparation efficiency is high.

2. In the present invention, four channels are formed by ring-shaped ring microchannels, and each ring microchannel adopts a misaligned micro channel, and the distance between the wide channel and the narrow channel is misaligned and both The diameter of the tube is small, so the microchannel has higher integration degree and better mixing effect, and the preparation of the blue perovskite quantum dot has low cost and high output.

3. The operation steps of the invention are simple, and the wavelength of the blue perovskite quantum dots prepared in the invention is accurately controlled at 430 nm to 487 nm, and the half width is between 29 and 33 nm, and the fluorescence quantum yield is much higher than that of the conventional blue carbon. The quantum dots, up to 85% or more, can be used in the fields of light-emitting diodes, LED light-emitting devices and LED display screens. Therefore, the prepared blue-light perovskite quantum dots have good effects and wide application range.

DRAWINGS

1 is a schematic view showing the combination of a microreactor for preparing a blue light perovskite quantum dot at a low temperature.

Figure 2 is a schematic view showing the structure of a reactor in the present invention;

3 is a schematic structural view of a microchannel in the present invention;

4 is an emission spectrum diagram of a blue light perovskite quantum dot prepared in Example 1.

5 is an emission spectrum of a blue light perovskite quantum dot prepared in Example 2.

6 is an emission spectrum of a blue light perovskite quantum dot prepared in Example 3.

7 is an emission spectrum of a blue light perovskite quantum dot prepared in Example 4.

8 is an emission spectrum of a blue light perovskite quantum dot prepared in Example 5.

Figure 9 is a graph showing the emission spectrum of a blue light perovskite quantum dot prepared in Example 6.

Among them, 1-first inlet, 2-second inlet, 3-third inlet, 4-product outlet, 5-precursor production zone, 6-precursor-toluene mixing zone, 7-fastener, 8-on Cover, 9-microchannel, 10-injector pump, 11-reactor, 12-temperature control module, 13-temperature controller, 14-water-cooled head, 15-hydraulic sink.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings.

Embodiment 1:

A microreactor for preparing a blue light perovskite quantum dot at a low temperature comprises a syringe pump, a reactor and a temperature control module, the injection pump is arranged above the reactor, and the temperature control module is connected with the reactor. The temperature control module includes a temperature controller, a water cooling head, and a constant temperature water tank.

As shown in Fig. 1, the upper cover is made of aluminum alloy, the temperature controller is installed in the center of the upper cover, the temperature controller is a thermocouple; the microchannel processed by the semiconductor refrigeration chip is electrically connected with the temperature controller; the water cooling head Adhere to the lower surface of the microchannel, and apply thermal grease with a thickness of 0.2mm-0.3mm on the contact surface of the water-cooling head and the microchannel; the water-cooling head is connected to the constant temperature water tank by a water pipe.

As shown in Figure 2, the reactor includes a microchannel, an upper cover; the microchannel is secured to the underside of the upper cover by fasteners. The fastener consists of a bolt and a nut.

As shown in FIG. 3, the microchannel is made of a semiconductor refrigerating sheet, and a cold processing surface of the semiconductor refrigerating sheet is formed by spraying a layer of boron nitride paint. The channel on the cold surface of the micro channel includes an in-line, a first channel, a second channel, a third channel, and a fourth channel that are sequentially connected; the first channel, the second channel, the third channel, and the fourth channel are each a group The loop-type microchannels are connected by pipelines; each set of loop-type microchannels is composed of four ring microchannels connected by a loop. Each ring microchannel in the group is a misaligned microchannel, one ring is a narrow channel, the other ring is a wide channel, the narrow channel diameter is 0.4mm-0.6mm, and the wide channel diameter is 0.9mm. -1.2mm, the misalignment distance of the wide channel and the narrow channel is 0.4mm-0.6mm, the wide channel has a circular arc shape, and the wide channel has an arc of 90°-150°, that is, the misalignment angle of the wide channel is 90°-150°. The connecting pipe between the first passage, the second passage, the third passage and the fourth passage has a diameter of 1.5 mm to 2 mm. The access road includes a main entrance, a first entrance and a second entrance, and the first entrance and the second entrance merge into the main entrance, and the main entrance and the first passage are connected. A first inlet is provided on the first access and a second inlet is provided on the second access. A third inlet is provided at the junction of the second passage and the third passage; the end of the fourth passage is provided with a product outlet.

The inlet channel, the first channel and the second channel constitute a precursor formation region, and the third channel and the fourth channel constitute a precursor and toluene mixing region.

A microreaction method for efficiently preparing a blue light perovskite quantum dot by a low temperature method, in the embodiment, specifically comprising the following steps:

(1) A microreactor for preparing a blue light perovskite quantum dot at a low temperature is assembled; in this embodiment, (a) the reactor is assembled, and the connecting pipe diameter between the channels is set to 1.5 mm. Each ring microchannel in the group is a misaligned channel, half is a narrow channel, the other half is a wide channel, the narrow channel diameter is 0.5mm, the wide channel diameter is 1.0mm, and the wide channel is misaligned. The distance is 0.5mm, the curvature of the wide channel is 120°; (b) the reactor and the temperature control module are connected, and the contact surface of the water-cooling head and the microchannel is coated with a thermal grease of 0.3 mm in thickness.

(2) 1 mL of oleylamine and 0.5 mL of oleic acid were weighed, placed in 10 mL of DMF solvent (dimethylformamide), and dissolved by stirring at 900 r/min.

(3) Weigh 0.147 g of PbBr ₂ and 0.043 g of CsBr solid (molar ratio of 2:1) on an electronic balance, and add them to the mixed solution obtained in the two steps (2), respectively, at 900 r/min. The rotation speed was evenly stirred to obtain a DMF-PbBr ₂ solution and a DMF-CsBr solution, respectively.

(4) Turn on the switch of the constant temperature water tank and the temperature controller. The water temperature of the constant temperature water tank is set to 5 °C, the water flow rate is set to 2.5 L/min, and the target temperature value of the temperature controller is set to 0 °C.

(5) After the actual temperature reaches the set target temperature value of 0 ° C, the DMF-PbBr ₂ solution and the DMF-CsBr solution are introduced from the first inlet and the second inlet of the reactor at a rate of 1 mL/min, respectively, from the third inlet. Toluene was passed at a rate of 5 mL/min and blue perovskite quantum dots were obtained from the product outlet.

4 is an emission spectrum of a blue light perovskite quantum dot prepared in the present embodiment. As can be seen from the figure, the obtained quantum dot emission wavelength is 487 nm, and the half width is 33 nm.

The abscissa in FIGS. 4 to 9 is the wavelength λ, the unit of the wavelength is nm, the ordinate is the fluorescence intensity A, and the unit of the fluorescence intensity is a.u.

Embodiment 2:

This embodiment differs from the first embodiment in that the target temperature value of the temperature controller in step (4) is set to -10 ° C, and other conditions remain unchanged; the same portions will not be described again.

FIG. 5 is an emission spectrum diagram of a blue light perovskite quantum dot prepared in the present embodiment. As can be seen from the figure, the obtained quantum dot emission wavelength is 465 nm, and the half width is 32 nm.

According to the method reported in the literature (CsPbX3 Quantum Dots for Lighting and Displays: Room-Temperature Synthesis, Photoluminescence Superiorities, Underlying Origins and White Light-Emitting Diodes [J]. Advanced Functional Materials, 2016, 26(15): 2435-2445), The blue light perovskite quantum dots were prepared by using a flask as a reaction vessel under conventional reaction system using PbBr ₂ , CsBr, PbCl ₂ and CsCl. According to the reference procedure, the fluorescence quantum efficiency was determined by using quinine sulfate as a reference. 64%.

According to the second embodiment, the blue light perovskite quantum dots prepared by using PbBr ₂ and CsBr under the microreactor were measured according to the reference procedure, and the fluorescence quantum efficiency was 88% with quinine sulfate as a reference.

Embodiment 3:

This embodiment differs from the first embodiment in that the target temperature value of the temperature controller in the step (4) is set to -20 ° C, and other conditions remain unchanged; the same portions will not be described again.

FIG. 6 is an emission spectrum diagram of a blue light perovskite quantum dot prepared in the present embodiment. As can be seen from the figure, the obtained quantum dot emission wavelength is 448 nm, and the half width is 30 nm.

Embodiment 4:

This embodiment differs from the first embodiment in that the target temperature value of the temperature controller in the step (4) is set to -30 ° C, and other conditions remain unchanged; the same portions will not be described again.

FIG. 7 is an emission spectrum diagram of a blue light perovskite quantum dot prepared in the present embodiment. As can be seen from the figure, the obtained quantum dot emission wavelength is 437 nm, and the half width is 29 nm.

Embodiment 5:

This embodiment differs from the first embodiment in that the target temperature value of the temperature controller in the step (4) is set to -40 ° C, and other conditions remain unchanged; the same portions will not be described again.

FIG. 8 is an emission spectrum diagram of a blue light perovskite quantum dot prepared in the present embodiment. As can be seen from the figure, the obtained quantum dot emission wavelength is 430 nm, and the half width is 32 nm.

Example 6:

This embodiment differs from the first embodiment in that the target temperature value of the temperature controller in the step (4) is set to -50 ° C, and other conditions remain unchanged; the same portions will not be described again.

FIG. 9 is an emission spectrum diagram of a blue light perovskite quantum dot prepared in the present embodiment. As can be seen from the figure, the obtained quantum dot emission wavelength is 430 nm, and the half width is 31 nm.

The above-described embodiments are preferred embodiments of the invention, but the embodiments of the invention are not limited to the above-described embodiments, and any other changes, modifications, substitutions, combinations, and simplifications may be made without departing from the spirit and scope of the invention. All should be equivalent replacement means, and are included in the scope of protection of the present invention.

Claims

A micro-reaction device for efficiently preparing blue-light perovskite quantum dots by low-temperature method, which comprises: a syringe pump, a reactor and a temperature control module;

The temperature control module includes a temperature controller, a water cooling head, and a constant temperature water tank;

The reactor comprises an upper cover and a microchannel, and the microchannel is fixed below the upper cover;

The injection pump is arranged above the reactor, the temperature controller is installed in the center of the surface of the upper cover plate and is electrically connected with the microchannel, the water cooling head is closely attached to the lower surface of the microchannel, and is applied on the contact surface of the water cooling head and the microchannel. There is a layer of thermal grease, and the water-cooled head is connected to the constant temperature water tank through a water pipe;

The upper surface of the microchannel is provided with an entrance channel, a first channel, a second channel, a third channel and a fourth channel which are sequentially connected, and the first channel, the second channel, the third channel and the fourth channel are a set of buckles The microchannels of the type are connected by pipelines, and each group of the buckle type microchannels comprises a plurality of annular microchannels connected in sequence, and the annular microchannels are connected by a loop, on the access road. A first inlet and a second inlet are provided, a third inlet is provided at the junction of the second passage and the third passage, and a product outlet is provided at the end of the fourth passage.
A microreactor for efficiently preparing a blue light perovskite quantum dot according to the low temperature method according to claim 1, wherein each of the ring-shaped microchannels comprises four annular microchannels connected in sequence, and the ring micro The channel is a misaligned microchannel, one ring is a narrow channel, the other ring is a wide channel, the wide channel and the narrow channel have a misalignment distance of 0.4 mm-0.6 mm, and the wide channel has a circular arc shape and a wide channel The curvature is 90°-150°.
The microreactor for efficiently preparing blue light perovskite quantum dots according to claim 2, wherein the narrow channel diameter is 0.4 mm-0.6 mm, and the wide channel diameter is 0.9 mm-1.2 mm. ,
A microreactor for efficiently preparing a blue light perovskite quantum dot according to claim 1, wherein the inlet channel comprises a main inlet, a first inlet and a second inlet, and the first inlet and the second inlet merge into the main inlet. In the tunnel, the main entrance is connected to the first passage; the first inlet is provided with a first inlet, and the second inlet is provided with a second inlet; between the first passage, the second passage, the third passage and the fourth passage The pipe diameter is 1.5mm-2mm.
A microreactor for efficiently preparing a blue light perovskite quantum dot according to the low temperature method according to claim 1, wherein the microchannel is made of a semiconductor refrigeration sheet, and the channel is processed on the cold surface of the semiconductor refrigeration sheet, and then sprayed. Layer boron nitride.
A microreaction method for efficiently preparing a blue light perovskite quantum dot by a low temperature method, and a microreactor for efficiently preparing a blue light perovskite quantum dot by the low temperature method according to any one of claims 1 to 5, wherein:

(1) Device assembly: a microreactor device for efficiently preparing a blue light perovskite quantum dot by a low temperature method;

(2) configuration mixed solution: the amount of oleylamine and oleic acid, placed in DMF solvent, stirred at 900-1200r / min, the volume ratio of DMF solvent, oleic acid, oleylamine is 20:2:1;

(3) Equipped with DMF-PbBr 2 solution and DMF-CsBr solution: PbBr 2 solid and CsBr solid were weighed on an electronic balance, and the molar ratio of PbBr 2 solid to CsBr solid was 2:1, and added to two portions respectively. The mixed solution disposed in the step (2) is further stirred at a speed of 900-1200 r/min to obtain a DMF-PbBr 2 solution and a DMF-CsBr solution, respectively;

(4) Set the temperature control module: open the switch of the constant temperature water tank and the temperature controller, the water temperature of the constant temperature water tank is set to 5 °C -10 °C, the water flow rate of the constant temperature water tank is set to 1.5L/min-2.5L/min, the temperature controller The target temperature value is set to -50 ° C - 0 ° C;

(5) conveying raw materials: when the actual temperature reaches the set target temperature value, the DMF-PbBr 2 solution and the DMF-CsBr solution are respectively introduced from the first inlet and the second inlet at a uniform rate, from the third inlet at a uniform rate. Passing in toluene;

(6) Product collection: The generated blue light perovskite quantum dots were collected at the product outlet.
A microreaction method for efficiently preparing a blue light perovskite quantum dot by a low temperature method according to claim 6, wherein a rate of the first inlet to the DMF-PbBr 2 solution and a second inlet to the DMF-CsBr solution The rate was 0.5 mL/min-1.5 mL/min, and the rate at which the third inlet was introduced into toluene was 5-10 mL/min.
A microreaction method for efficiently preparing a blue light perovskite quantum dot by a low temperature method according to claim 6, wherein the concentration of the DMF-PbBr 2 solution and the DMF-CsBr solution are both 0.2 mmoL/mL-0.4 mmoL/mL. .
The microreaction method for efficiently preparing a blue light perovskite quantum dot according to claim 6, wherein in the step (2), the oleylamine is 1 mL, the oleic acid is 0.5 mL, and the DMF solvent is 10 mL.
A microreaction method for efficiently preparing a blue light perovskite quantum dot by a low temperature method according to claim 6, wherein 0.147 g of DMF-PbBr 2 solid and 0.043 g of CsBr solid are weighed.