WO2022016785A1

WO2022016785A1 - Method for preparing doped mxene quantum dots, and optical film and qled

Info

Publication number: WO2022016785A1
Application number: PCT/CN2020/136136
Authority: WO
Inventors: 叶炜浩
Original assignee: Tcl科技集团股份有限公司
Priority date: 2020-07-24
Filing date: 2020-12-14
Publication date: 2022-01-27
Also published as: CN113969171A

Abstract

Provided are a method for preparing doped MXene quantum dots and an optical film and QLED. The method for preparing doped MXene quantum dots comprises the following steps: providing MXene; dispersing MXene in a mixed solution of concentrated nitric acid and concentrated sulfuric acid to obtain an MXene quantum dot solution; and adding a sulfur source and/or a nitrogen source to the MXene quantum dot solution and reacting same to prepare doped MXene quantum dots. The MXene quantum dots obtained by dispersing the MXene with a mixed solution of concentrated nitric acid and concentrated sulfuric acid are more pure and more conducive to doping, and doping MXene quantum dots with an inorganic sulfur source and/or an inorganic nitrogen source can change the surface defects of the quantum dots and result in hydrogen bonds which change the size of quantum dots, such that the quantum dots emit light of different wavelengths.

Description

Preparation method of doped MXene quantum dots and optical thin films and QLEDs

priority

The present disclosure claims priority to Chinese Patent Application No. 202010725381.5 filed on Jul. 24, 2020, the entire contents of which are incorporated herein by reference.

technical field

The present disclosure relates to the technical field of quantum dot material preparation, and in particular, to a preparation method of doped MXene quantum dots, optical films and QLEDs.

Background technique

MXene is a kind of metal carbide and metal nitride materials with a two-dimensional layered structure and a sheet-like structure similar to that of sheets stacked together. It is a two-dimensional crystal of transition metal carbides or carbonitrides, and the chemical formula is M. _n+1 X _n , n=1, 2 or 3, M is an early transition metal element, and X is carbon or/and nitrogen.

Because of their unique structural, electronic and chemical properties, MXenes have potential applications in many fields, including as energy storage materials, sensors, and catalysts, and quantum dots derived from 2D inorganic MXenes have begun to received considerable attention.

SUMMARY OF THE INVENTION

At present, the preparation methods of MXene quantum dots mainly include chemical solution growth method, epitaxial growth method and electric field confinement method.

However, in the actual use process, the inventors found that in addition to their respective disadvantages such as low conductivity, high cost and low yield, the above preparation methods also have a common disadvantage, that is, the MXene quantum The emission wavelengths of the dots are not controllable.

Based on this, according to the first aspect of the present disclosure, there is provided a method for preparing doped MXene quantum dots, comprising the following steps:

provide MXene;

Disperse MXene in a mixed solution of concentrated nitric acid and concentrated sulfuric acid to obtain an MXene quantum dot solution;

A sulfur source and/or a nitrogen source is added to the MXene quantum dot solution for reaction to prepare doped MXene quantum dots.

According to a second aspect of the present disclosure, there is provided an optical film comprising a hydrophilic polymer and doped MXene quantum dots dispersed in the hydrophilic polymer, the doped MXene quantum dots being prepared by the method described above be made of.

According to a third aspect of the present disclosure, there is provided a QLED comprising a light-emitting layer, wherein the light-emitting layer is made of the optical film as described above.

According to the present disclosure, there is provided a preparation method capable of obtaining doped MXene quantum dots emitting light of different wavelengths.

Description of drawings

FIG. 1 is a schematic flowchart of a method for preparing doped MXene quantum dots according to an embodiment of the present disclosure.

detailed description

It should be understood that the specific embodiments described herein are only used to explain the present disclosure, but not to limit the present disclosure.

As shown in FIG. 1 , the preparation method of the doped MXene quantum dots according to the present disclosure includes the following steps:

S100, provide MXene;

S200, dispersing MXene in a mixed solution of concentrated nitric acid and concentrated sulfuric acid to obtain an MXene quantum dot solution;

S300, adding a sulfur source and/or a nitrogen source to the MXene quantum dot solution for reaction to prepare doped MXene quantum dots.

For step S100, the present disclosure does not limit the preparation method of MXene. For example, MXenes prepared by any preparation method such as chemical liquid phase etching can be provided.

For example, in some embodiments, step S100 may include the following steps:

S101, ball milling MXene monomer into MXene powder by ball milling;

S102, in an inactive atmosphere such as nitrogen or an inert gas, the MXene powder is heated to 1000-1400° C. for calcination, and the powder is obtained by grinding after calcination;

S103 , adding the powder to the HF solution, separating the solid from the liquid, and washing and drying the solid part to obtain MXene. MXene may be selected from one of Ti ₂ C, Ti ₃ C ₂ , (Ti _0.5 , Nb _0.5 ) ₂ C, (V _0.5 , Cr _0.5 ) ₃ C ₂ , Nb ₂ C, Ti ₃ CN and Ta ₄ C ₃ or more.

Unless otherwise specified, in the present disclosure, concentrated nitric acid refers to _{a nitric acid solution with a mass content of HNO 3} of 68% or more, and concentrated sulfuric acid refers to a sulfuric acid solution with a mass content of _{H 2} SO _{4 of 70% or more.}

In some embodiments, in step S200, a mixed solution of concentrated nitric acid and concentrated sulfuric acid is used to disperse the MXene. This is because, the inventors found that when etching is performed using, for example, an HF solution in step S100, there may be cases where the powder is not completely broken. At the same time, the inventors also unexpectedly found that the above mixed solution can oxidize the parts that are not completely disconnected, so that the powder is basically completely disconnected to form quantum dot particles. In addition, the etching of the mixed solution is relatively mild compared to the strong etching of, for example, an HF solution, and it is easy to obtain quantum dot particles of a predetermined size.

In order to ensure that the mixed solution has the appropriate strong oxidizing properties to break the powder substantially completely, in some embodiments, the volume of concentrated nitric acid is less than the volume of concentrated sulfuric acid in the mixed solution, and in some embodiments, the concentrated nitric acid is The volume ratio of concentrated nitric acid and concentrated sulfuric acid is 1:(2-5), which makes strong oxidizing property more appropriate. In some embodiments, the volume ratio of concentrated nitric acid and concentrated sulfuric acid is 1:3, which is the most suitable for strong oxidizing property.

In addition, the inventors also unexpectedly found that the preparation of functionalized MXene by chemical liquid phase etching method is different from the existing chemical liquid etching method, which is affected by the concentration of the chemical etchant and the reaction time (for example, if the reaction time is too short or the etchant If the corrosiveness is too weak, MXene may not be prepared, and if the etchant is too corrosive, the MAX phase may be completely dissolved), and only two-dimensional systems with functional groups such as F, OH, etc. on the surface can be obtained. Compared with the case where pure MXene quantum dots cannot be obtained, the MXene is dispersed by using a mixed solution of concentrated nitric acid and concentrated sulfuric acid (for example, when MXene is prepared by chemical liquid etching method, after etching with HF solution, using the above The mixed solution is dispersed, which can prevent MXene from being corroded and dissolved by the HF solution), and the obtained MXene quantum dots are purer. Meanwhile, compared with MXene with 2D system, the obtained MXene QDs with 0D system have better dispersibility in aqueous and non-aqueous media, which is more favorable for functionalization or doping.

In other embodiments, in step S200, the ratio of MXene to the mixed solution is (1-5) g: 10 mL, such as 1 g: 10 mL, 2 g: 10 mL, 3 g: 10 mL, 5 g: 10 mL, and the like. In such a ratio, the strong oxidizing property of the mixed solution can be fully exerted, and MXene can be dispersed into quantum dot particles in a predetermined size. If the ratio is less than 1g:10mL, it may lead to excessive etching, so that the structure of MXene itself is destroyed, and quantum dots cannot be formed. If the ratio is greater than 5g:10mL, it may lead to insufficient etching, so that MXene is still in the bulk phase material, and no quantum dots are formed.

In still other embodiments, in step S200, after dispersing the MXene in the mixed solution of concentrated nitric acid and concentrated sulfuric acid, the method further includes: heating, cooling to room temperature, and adjusting the pH value to neutrality to obtain an MXene quantum dot solution. Here, the heating temperature is 90 to 110°C, for example, 90°C, 100°C, 105°C, 110°C, and the like. Heating at this temperature can promote the etching of MXene by the mixed solution. The heating time is 10-15h, such as 10h, 12h, 14h and 15h. Adjusting the pH to neutrality can make the resulting MXene quantum dots purer and more favorable for functionalization or doping.

In some embodiments, in step S300, the reaction temperature is 150-170°C, such as 150°C, 160°C, 165°C, and 170°C, etc., and the reaction time is 12-15h, such as 12h, 13h, 14h, and 15h. etc. for a more complete response. In other embodiments, the reaction is a hydrothermal reaction.

In other embodiments, in step S300, after the reaction is performed, purification treatment may also be performed. Here, the purification treatment can be performed by washing the obtained product with a dialysis membrane. Further, the molecular weight cut-off of the dialysis membrane may be 1000-2000 Da, such as 1000 Da, 1200 Da, 1500 Da and 2000 Da, etc., and the number of cleanings may be 2 to 4 times, such as 2 times, 3 times and 4 times.

In still other embodiments, in step S300, both the sulfur source and the nitrogen source are inorganic substances. Compared with the organic matter, especially the case where the nitrogen source is urea, the inorganic matter can make the doping more sufficient, that is, the sulfur source and the nitrogen source as the inorganic matter can enter the MXene more easily, especially when the reaction is a hydrothermal reaction. In some embodiments, the sulfur source may be selected from sodium thiosulfate _{_{_{(Na 2 S 2 O 3)}}} , sulfur powder, sodium sulfide (Na ₂ S), sodium sulfite (Na ₂ SO ₃₎ and sodium dithionite (Na ₂ One or more of S ₂ O ₆ ), in some embodiments, the nitrogen source may be selected from ammonia (NH ₃ ·H ₂ O), ammonium chloride (NH ₄ Cl), and ammonium bicarbonate (NH ₄ HCO) ₃ ) one or more of.

In still other embodiments, in step S300, the ratio of the MXene quantum dot solution to the sulfur source is 1mL:(0.05-0.1)g, such as 1mL:0.05g, 1mL:0.06g, 1mL:0.08g and 1mL:0.1 g, etc., further, the ratio of MXene quantum dot solution to nitrogen source is 1 mL: (0.7-1.4) mmol, such as 1: 0.7 mmol, 1: 1.05 mmol, 1: 1.26 mmol and 1: 1.4 mmol, etc. It should be understood that the same is true for the ratio when both a sulfur source and a nitrogen source are used.

By adopting the above ratio, especially after dispersing MXene with a mixed solution of concentrated nitric acid and concentrated sulfuric acid (ie, the combination of step S200 and step S300 ), the effective doping of MXene quantum dots with a sulfur source and/or a nitrogen source can be achieved , which in turn changes the surface electron distribution of MXene quantum dots, produces different defects, forms hydrogen bonds with bound water, and forms a strong and ordered hydrogen bond network through COC bonds. The generated hydrogen bond network changes the size of the quantum dots, thereby The obtained doped quantum dots are made to emit light of different wavelengths.

S When a sulfur source present disclosure doped, formed in the quantum dot MXene system OS, S ₂ or the CSC, so that less of forming an electronic defect, respective hydrogen bonds less, smaller size can be obtained doped doped MXene quantum dots, so that the emission wavelength of S-doped MXene quantum dots corresponds to blue light. When the sulfur source of the present disclosure is used for doping, N will form a pyrrole-like (structure of

) C=N bond. Due to the formation of the C=N bond, the electron defect site has a strong negative type, which will produce electron shrinkage defects, so it is easy to form more hydrogen bonds with water molecules (the formation barrier of CN or C=N bond is smaller than that of CS bond, so it is easier to form hydrogen bonds when doped with N), so that the emission wavelength of N-doped MXene quantum dots corresponds to green light. When both sulfur and nitrogen sources of the present disclosure are used, the presence of N increases the formation of pyrrole-like CNC bonds, and in addition to C=N bonds, CSC bonds also increase the formation of electron defects, ultimately forming larger hydrogens Bond network, due to the formation of hydrogen bonds, the size of the particles will become larger, so the corresponding delocalized π electron energy levels will drop, resulting in a red shift in wavelength, so that the emission wavelength of S/N doped MXene quantum dots corresponds to red light .

Therefore, the doped MXene quantum dots prepared according to the embodiments of the present disclosure can emit light of different wavelengths, and can be applied to the fields of full-color quantum dot illumination and display.

In addition, the present disclosure also provides an optical film comprising a hydrophilic polymer and doped MXene quantum dots dispersed in the hydrophilic polymer, the doped MXene quantum dots being prepared by any of the above embodiments, The mass ratio of the two can be 1:8, such as 4:7, 1:2, 1:4 and 1:5, etc.

Compared with the case of using the hydrophobic polymer, the inventors found that the use of the hydrophilic polymer can achieve the effect of more uniform mixing with the doped MXene quantum dots without the need to modify the surface of the MXene quantum dots.

In some embodiments, the hydrophilic polymer may be selected from one or more of polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol, and polyethylene oxide.

In addition, the present disclosure also provides a QLED, including a light-emitting layer, and the light-emitting layer is made of any of the above optical films.

In the present disclosure, the types and fabrication methods of QLEDs are not limited, and known QLED types and fabrication methods may be employed, such as those described in CN106252522A, the entire contents of which are incorporated herein by reference. Further, the QLED may also include, but is not limited to, a cathode, an anode, and optional functional layers, such as a hole injection layer and/or a hole transport layer, an electron injection layer and/or an electron transport layer, and the like. The hole injection layer and/or the hole transport layer may be provided between the anode and the light emitting layer, and the electron injection layer and/or the electron transport layer may be provided between the cathode and the light emitting layer.

In the present disclosure, the materials and parameters such as thicknesses of the cathode, anode, and functional layers are not limited, as long as the present disclosure can be realized, and details are not repeated here.

The present disclosure will be described in detail below through specific embodiments.

Example 1

(1) MXene: Ti ₃ C ₂ Preparation of

_{Ti 2} AlC and TiC with a molar ratio of 1:1 were ball-milled into mixed powder by ball milling, and the milling time was 10h. Then, the temperature was raised to 1200°C at 5°C/min, calcined at 1200°C for 3 h under argon protection, and then crushed with a mortar and pestle to obtain MXene powder. Next, 5 g of MXene powder was added to 5 mL of HF solution (50 mol%), stirred at 25° C. for 3 h, and the suspension was washed twice with deionized water and centrifuged to obtain Ti ₃ C ₂ wet deposits. Finally, the wet deposit Ti ₃ C ₂ was dried for 14h in a vacuum oven at 70 deg.] C, to give MXene: Ti ₃ C _2.

(2) _{Preparation of Ti 3} C ₂ quantum dot solution

1 g of Ti ₃ C _{2 was} added to 10 mL of a mixed solution of concentrated nitric acid and concentrated sulfuric acid (volume ratio of 1:2), and heated under reflux at 100° C. for 12 h to disperse _{Ti 3} C _{2 .} Then, it was diluted with 100 mL of deionized water and cooled to 25°C in an ice bath. Next, the obtained product was added to NaOH until the pH value reached 7 to obtain a Ti ₃ C ₂ quantum dot solution.

(3) Preparation of N-doped Ti ₃ C _{2 quantum dots}

100 μL (0.7 mmol) of NH ₃ ·H ₂ O was added to 1 mL of Ti ₃ C ₂ quantum dot solution, then transferred to a 50 mL reaction kettle, heated to 150° C. for 15 h. Next, after the reaction, the product was washed twice with a dialysis membrane (with a molecular weight cut-off of 1000 Da) and dried to finally obtain N-doped Ti ₃ C ₂ quantum dots.

Preparation of (4) based on the N-doped optical film of Ti ₃ C ₂ quantum dots

Add 0.1 g of N-doped Ti ₃ C ₂ quantum dots to 1 mL of water to obtain N-doped Ti ₃ C ₂ quantum dots solution, and then uniformly mix 1 mL of quantum dot solution and 0.5 g of polyvinylpyrrolidone (PVP), N-doped Ti ₃ C ₂ quantum dots/PVP composites were obtained. Next, the N-doped Ti ₃ C ₂ quantum dot/PVP composite material was poured into a petri dish, and cured and aged at room temperature for 3 days to obtain an N-doped Ti ₃ C ₂ quantum dot/PVP thin film.

Example 2

(1) Preparation of MXene: (Ti _0.5 ,Nb _0.5 ) ₂ C

(Ti _0.5 , Nb _0.5 ) ₂ AlC was ball-milled into powder by ball milling, and the milling time was 15h. Then, the temperature was raised to 1300°C at 5°C/min, calcined at 1300°C for 2.5 h under argon protection, and then crushed with a mortar and pestle to obtain MXene powder. Next, 6 g of MXene powder was added to 5 mL of HF solution (50 mol%), stirred at 25° C. for 4 h, the suspension was obtained, washed twice with deionized water, and centrifuged to obtain (Ti _0.5 , Nb _0.5 ) ₂ C Wet deposits. Finally, the (Ti _0.5 , Nb _0.5 ) ₂ C wet deposit was dried in a vacuum oven at 70° C. for 14 h to obtain MXene: (Ti _0.5 , Nb _0.5 ) ₂ C.

(2) _{Preparation of (Ti 0.5} ,Nb _0.5 ) ₂ C quantum dot solution

3g of (Ti _0.5 , Nb _0.5 ) _{2 was} added to 10 mL of a mixed solution of concentrated nitric acid and concentrated sulfuric acid (volume ratio of 1:3), and heated under reflux for 10 hours at 110° C. to disperse _{(Ti 0.5} , Nb _0.5 ) ₂ , diluted with 100 mL of deionized water, and cooled to 25 °C in an ice bath. Next, the obtained product was added to NaOH until the pH value reached 7 to obtain a (Ti _0.5 , Nb _0.5 ) ₂ C quantum dot solution.

(3) Preparation of S-doped (Ti _0.5 , Nb _0.5 ) ₂ C quantum dots

0.05g of Na ₂ S ₂ O _{3 was} added to 1 mL of (Ti _0.5 , Nb _0.5 ) ₂ C quantum dot solution, then transferred to a 50 mL reaction kettle, heated to 160° C. for 14 h. Then, after the reaction, a dialysis membrane was used (Molecular weight cut-off is 1500 Da), the product is washed 3 times and dried to finally obtain S-doped (Ti _0.5 , Nb _0.5 ) ₂ C quantum dots.

(4) Preparation of optical thin films based on S-doped (Ti _0.5 , Nb _0.5 ) _{2 C quantum dots}

Add 0.4 g of S-doped (Ti _0.5 , Nb _0.5 ) ₂ C quantum dots to 1 mL of water to obtain S-doped (Ti _0.5 , Nb _0.5 ) ₂ C quantum dot solution, and then uniformly mix 1 mL of quantum dot solution and 0.8 g of polyacrylic acid (PAA) was used to obtain S-doped (Ti _0.5 , Nb _0.5 ) ₂ C quantum dot/PAA composite material. Next, the S-doped (Ti _0.5 , Nb _0.5 ) ₂ C quantum dot/PAA composite material was poured into a petri dish, and cured and aged at room temperature for 3 days to obtain S-doped (Ti _0.5 , Nb _0.5 ) ₂ C Quantum dots/PAA films.

Example 3

(1) MXene: Ta ₄ C ₃ Preparation of

The Ta ₄ AlC ₃ was ball-milled into powder by ball milling, and the milling time was 12h. Then, the temperature was raised to 1100°C at 5°C/min, calcined at 1100°C for 4 h under argon protection, and then crushed with a mortar and pestle to obtain MXene powder. Next, 8 g of MXene powder was added to 5 mL of HF solution (50 mol%), stirred at 25 °C for 3.5 h, the suspension was obtained, washed three times with deionized water, and centrifuged to obtain a Ta ₄ C ₃ wet deposit . Finally, the Ta ₄ C ₃ wet deposit was dried in a vacuum oven at 70° C. for 14 h; MXene: Ta ₄ C _{3 was obtained} .

(2) _{Preparation of Ta 4} C ₃ quantum dot solution

5 g of Ta ₄ C ₃ powder was added to a mixed solution of 10 mL of concentrated nitric acid and concentrated sulfuric acid (volume ratio of 1:5), and heated under reflux at 90° C. for 15 h to disperse the powder. Then, it was diluted with 100 mL of deionized water and cooled to 25°C in an ice bath. Next, the obtained product was added to NaOH until the pH value reached 7 to obtain a Ta ₄ C ₃ quantum dot solution.

(3) Preparation of S/N Doped Ta ₄ C _{3 Quantum Dots}

0.1 g of Na ₂ S ₂ O ₆ and 1.4 mmol of NH ₄ Cl were added to 1 mL of Ta ₄ _{C 3} quantum dot solution, then transferred to a 50 mL reaction kettle, heated to 170° C. for 13 h, and dialyzed after the reaction. (Molecular weight cut-off is 2000 Da), the product is washed 4 times and dried to finally obtain N/S doped Ta ₄ C ₃ quantum dots.

(4) Preparation of optical thin films based on S/N doped Ta ₄ C _{3 quantum dots}

Add 0.4 g of S/N doped Ta ₄ C ₃ quantum dots into 1 mL of water to obtain N/S doped Ta ₄ C ₃ quantum dot solution, and then uniformly mix 1 mL of quantum dot solution and 0.7 g of polyepoxy Ethane (PEO) to obtain N/S doped Ta ₄ C ₃ quantum dots/PEO composites. Next, the N/S doped Ta ₄ C ₃ quantum dots/PEO composite material was poured into a petri dish, and cured and aged at room temperature for 3 days to obtain N/S doped Ta ₄ C ₃ quantum dots/PEO thin films.

While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

A preparation method of doped MXene quantum dots, comprising the following steps:

provide MXene;

Disperse MXene in a mixed solution of concentrated nitric acid and concentrated sulfuric acid to obtain an MXene quantum dot solution;

A sulfur source and/or a nitrogen source is added to the MXene quantum dot solution for reaction to prepare doped MXene quantum dots.
The preparation method according to claim 1, wherein the ratio of MXene to the mixed solution is (1-5) g: 10 mL,

In the mixed solution, the volume of concentrated nitric acid is less than that of concentrated sulfuric acid.
preparation method according to claim 2, wherein, the volume ratio of concentrated nitric acid and concentrated sulfuric acid is 1:(2～5).
preparation method according to claim 3, wherein, the volume ratio of concentrated nitric acid and concentrated sulfuric acid is 1:3.
The preparation method according to claim 1, wherein both the sulfur source and the nitrogen source are inorganic substances.
preparation method according to claim 5, wherein, the sulfur source is selected from one or more in sodium thiosulfate, sulfur powder, sodium sulfide, sodium sulfite and sodium dithionate,

The nitrogen source is selected from one or more of ammonia water, ammonium chloride and ammonium bicarbonate.
The preparation method according to claim 1, wherein the ratio of the MXene quantum dot solution to the sulfur source is 1 mL: (0.05-0.1) g,

The ratio of MXene quantum dot solution to nitrogen source is 1 mL:(0.7-1.4) mmol.
The preparation method according to claim 1, wherein, after MXene is dispersed in the mixed solution of concentrated nitric acid and concentrated sulfuric acid, the preparation method further comprises:

Heating, cooling to room temperature, and adjusting the pH value to neutrality to obtain MXene quantum dot solution,

Wherein, the heating temperature is 90-110°C, and the time is 10-15h.
The preparation method according to claim 1, wherein the reaction temperature is 150-170° C., and the time is 12-15 h.
The preparation method according to claim 1, wherein, MXene is selected from Ti 2 C, Ti 3 C 2 , (Ti 0.5 , Nb 0.5 ) 2 C, (V 0.5 , Cr 0.5 ) 3 C 2 , Nb 2 C, Ti Ta 3 CN and one or more of the 4 C 3.
The preparation method according to claim 1, wherein, after the reaction, a purification treatment is also performed to obtain doped MXene quantum dots,

Purification is carried out by washing the obtained product with a dialysis membrane.
The preparation method according to claim 11, wherein the molecular weight cut-off of the dialysis membrane is 1000-2000 Da.
An optical film comprising a hydrophilic polymer and doped MXene quantum dots dispersed in the hydrophilic polymer,

The doped MXene quantum dots are prepared by the preparation method according to any one of claims 1 to 12.
The optical film of claim 13, wherein the hydrophilic polymer is selected from one or more of polyvinylpyrrolidone, polyacrylic acid, polyvinyl alcohol and polyethylene oxide.
14. The optical film of claim 13, wherein the optical film consists of a hydrophilic polymer and doped MXene quantum dots dispersed in the hydrophilic polymer.
The optical film of claim 13, wherein the mass ratio of the hydrophilic polymer to the doped MXene quantum dots is 1:(1-8).
A QLED comprising a light-emitting layer, wherein the light-emitting layer is made of the optical film as claimed in claim 8 or 9.