Core-shell structure quantum dot and quantum dot product for photoluminescence

Abstract

The present application provides a core-shell structure quantum dot for photoluminescence, comprising a crystal core, a first shell layer covering the crystal core, and a second shell layer covering the first shell layer, wherein the energy band gap of the first shell layer is between the energy band gap of the crystal core and the energy band gap of the second shell layer, and at least one layer of the crystal core, the first shell layer, and the second shell layer comprises a light-absorbing material, and the molar absorption coefficient of the light-absorbing material is greater than 10 5 L / mol.cm, the light-absorbing material can effectively improve the absorbance of the core-shell structure quantum dots at a wavelength of 450nm, thereby obtaining quantum dot products containing the core-shell structure quantum dots with excellent optical properties.

Description

Technical Field

[0001] The present application belongs to the field of nanotechnology, and specifically relates to a core-shell structure quantum dot for photoluminescence and a quantum dot product. Background Art

[0002] Quantum dots, also known as semiconductor nanocrystals, are a new type of semiconductor nanomaterial with a size of 1-10 nm. Due to quantum size effects and dielectric confinement, they possess unique photoluminescence (PL) and electroluminescence (EL) properties. Compared with traditional organic fluorescent dyes, quantum dots offer excellent optical properties such as high quantum yield, high photochemical stability, resistance to photolysis, broad excitation, narrow emission, high color purity, and tunable luminescence color by controlling the quantum dot particle size. These properties hold broad application prospects in the display field, with quantum dot photoluminescent films, one of the most popular applications, becoming a research hotspot.

[0003] At present, InP quantum dots have excellent luminescence performance and cadmium-free characteristics, and have a promising future in display applications. However, InP also has some shortcomings, such as low quantum yield (QY) and low absorbance (OD) at 450nm wavelength. 450 ) is low and cannot meet the needs of back-end photoluminescence applications, which restricts the development of commercial applications of InP quantum dots. Summary of the Invention

[0004] In response to the above technical problems, the present application provides a core-shell structure quantum dot for photoluminescence, comprising a crystal core, a first shell layer covering the crystal core, and a second shell layer covering the first shell layer, wherein the energy band gap of the first shell layer is between the energy band gap of the crystal core and the energy band gap of the second shell layer, and at least one layer of the crystal core, the first shell layer, and the second shell layer comprises a light-absorbing material, and the molar absorption coefficient of the light-absorbing material is greater than 10 5 L / mol.cm, so that the core-shell structure quantum dots can better absorb blue light.

[0005] Furthermore, the energy band gap of the light absorbing material is not less than the energy band gap of the crystal core.

[0006] Furthermore, the energy band gap of the light absorbing material is 2.0 to 2.7 eV.

[0007] Furthermore, the energy band gap of the core-shell structure quantum dots is 2.0 to 3.6 eV.

[0008] Furthermore, the crystal core, the first shell layer, and the second shell layer all contain the light absorbing material;

[0009] Preferably, the molar percentage of the light absorbing material gradually decreases from the crystal core to the second shell layer.

[0010] Furthermore, the lattice mismatch between the crystal core, the first shell layer, and adjacent layers of the second shell layer is less than 10%.

[0011] Furthermore, the light absorbing material accounts for 7 to 50 wt % of the core-shell structure quantum dots.

[0012] Furthermore, the light-absorbing material comprises metal elements and non-metal elements, the metal elements include at least one of In, Ga, Pb, Cu, Mg, Al, Ge, Co, Cd, and Mn, and the non-metal elements include at least one of S, Se, P, Te, and O;

[0013] Preferably, the light-absorbing material is at least one of GaInS, GaInSe, ZnGaSe, ZnGaS, CdGaSe, CdGaS, ZnCdGaS, ZnCdGaSe, GaInSeS, ZnGaSeS, and CdGaSeS.

[0014] Furthermore, the melting point of the light absorbing material is not lower than the melting point of the crystal core.

[0015] The present application also provides a quantum dot product, comprising the above-mentioned core-shell structure quantum dots for photoluminescence.

[0016] Beneficial effect: The core-shell structure quantum dot for photoluminescence of the present application comprises a crystal core, a first shell layer coated outside the crystal core, and a second shell layer coated on the first shell layer, wherein the energy band gap of the first shell layer is between the energy band gap of the crystal core and the energy band gap of the second shell layer, and at least one layer of the crystal core, the first shell layer, and the second shell layer comprises a light-absorbing material, and the molar absorption coefficient of the light-absorbing material is greater than 10 5 L / mol.cm, the light-absorbing material of the present application can effectively improve the absorbance of the core-shell structure quantum dots at a wavelength of 450nm, thereby obtaining quantum dot products containing the core-shell structure quantum dots with excellent optical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a TEM image of the core-shell structured quantum dots of Example 9 of the present application;

[0018] Figure 2 This is a TEM image of the core-shell structured quantum dots of Example 10 of the present application;

[0019] Figure 3 This is a comparison chart of the absorption spectra of the core-shell structure quantum dots of Example 9 and Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0020] The following will describe the technical solutions in the embodiments of the present application in detail in combination with the embodiments of the present application. It should be noted that the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0021] As described in the background art, in the prior art, due to the low absorbance of InP quantum dots at a wavelength of 450 nm and the low quantum dot yield, the optical properties of the photoluminescent film are affected, which restricts the development of quantum dot photoluminescent films.

[0022] Based on this, the present application provides a core-shell structure quantum dot for photoluminescence, comprising a crystal core, a first shell layer covering the crystal core, and a second shell layer covering the first shell layer, wherein the energy band gap of the first shell layer is between the energy band gap of the crystal core and the energy band gap of the second shell layer, and at least one layer of the crystal core, the first shell layer, and the second shell layer comprises a light-absorbing material, and the molar absorption coefficient of the light-absorbing material is greater than 10 5 L / mol.cm, which can effectively improve the overall absorbance of the core-shell structure quantum dots at a wavelength of 450nm.

[0023] It is understood that the molar absorptivity of the present application refers to the measure of the absorption capacity of a substance to light of a certain wavelength, and refers to the absorbance of a solution at a certain wavelength, when the concentration is 1 mol / L and the optical path is 1 cm, at a wavelength of 450 nm, and is represented by ε. The larger the ε, the stronger the ability of the solution to absorb light, and the higher the sensitivity of the corresponding spectrophotometric determination. The absorbance at a wavelength of 450 nm in the present application refers to the absorbance of quantum dots under 450 nm blue light excitation, generally expressed as OD 450 express.

[0024] The second shell layer of the present application may be the outermost shell layer, which may include one or more layers and may be arranged as required.

[0025] In a specific embodiment of the present application, the energy band gap of the light-absorbing material is not less than the energy band gap of the crystal core, thereby improving the QY of the core-shell structure quantum dots and avoiding the quantum hydrazine effect.

[0026] In another specific embodiment of the present application, the energy band gap of the light-absorbing material is 2.0 to 2.7 eV, so that a higher absorbance at a wavelength of 450 nm can be obtained without reducing the quantum yield.

[0027] In another specific embodiment of the present application, the band gap of the core-shell quantum dots is 2.0 to 3.6 eV, such as 2.0 eV, 2.1 eV, 2.2 eV, 2.3 eV, 2.5 eV, 2.6 eV, 2.7 eV, 2.8 eV, 2.9 eV, 3.0 eV, 3.1 eV, 3.2 eV, 3.3 eV, 3.4 eV, 3.5 eV, and 3.6 eV. The band gap of the green core-shell quantum dots can be 2.0 to 2.7 eV, and the band gap of the red core-shell quantum dots can be 2.0 to 3.1 eV, so as to increase the blue light absorption intensity and obtain higher quantum efficiency.

[0028] In another specific embodiment of the present application, the core, the first shell, and the second shell of the core-shell structure quantum dots all contain light-absorbing materials, thereby achieving a better blue light absorption effect.

[0029] In a preferred embodiment, the molar percentage of the light-absorbing material contained in the core-shell structure quantum dots gradually decreases from the crystal core to the second shell layer, so that the blue light absorption ability of the core-shell structure quantum dots is stronger.

[0030] In another specific embodiment of the present application, the lattice mismatch of the core-shell structure quantum dots is less than 10%, and the lattice mismatch between adjacent layers of the crystal core, the first shell, and the second shell is less than 10%, thereby allowing the first shell and the second shell to grow better in sequence on the crystal core.

[0031] In another specific embodiment of the present application, the light absorbing material accounts for 7 to 50 wt % of the core-shell structure quantum dots, thereby absorbing more blue light.

[0032] In another specific embodiment of the present application, the light-absorbing material contains metal elements and non-metal elements, the metal elements include at least one of In, Ga, Pb, Cu, Mg, Al, Ge, Co, Cd, and Mn, and the non-metal elements include at least one of S, Se, P, Te, and O, thereby helping the core-shell structure quantum dots to absorb more blue light.

[0033] In a preferred embodiment, the light-absorbing material can be at least one of GaInS, GaInSe, ZnGaSe, ZnGaS, CdGaSe, CdGaS, ZnCdGaS, ZnCdGaSe, GaInSeS, ZnGaSeS, and CdGaSe. These light-absorbing materials have better blue light absorption effects and stronger stability.

[0034] In another specific embodiment of the present application, the melting point of the light-absorbing material in the core-shell structure quantum dots is not lower than the melting point of the crystal core. The light-absorbing material effectively protects the luminescent material of the crystal core, so that the core-shell structure quantum dots have better thermal stability and can maintain a high quantum efficiency for a long time.

[0035] In the present application, the crystal core contains at least one luminescent substance selected from group II-VI compounds and group III-V compounds, and the obtained core-shell structure quantum dots have better light absorption properties. The quantum dot photoluminescent film prepared from the core-shell structure quantum dots has excellent optical properties. For example, Group II-VI compounds may include: CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnT e. CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe or combinations thereof. The III-V compounds may include: GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, InZnP, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb or combinations thereof.

[0036] In a preferred embodiment, the core of the core-shell quantum dot of the present application preferably comprises a III-V compound. 450 When the core-shell structure quantum dots contain the light-absorbing material of the present application, the absorbance of the core-shell structure quantum dots at a wavelength of 450 nm will be effectively improved.

[0037] The present application also provides a quantum dot product comprising the above-mentioned core-shell structure quantum dots. Under the action of the light-absorbing material in the core-shell structure quantum dots, the quantum dot product has high light conversion efficiency and excellent light extraction performance.

[0038] The core-shell structure quantum dots of the present application can be prepared as a quantum dot composition, and a quantum dot photoluminescent film can be prepared by inkjet printing. At this time, the viscosity of the quantum dot composition is, for example, 2 to 20 cp, and the surface tension is, for example, 20 to 40 mN / m, so that the inkjet stability of the quantum dot composition is better.

[0039] The core-shell structure quantum dots of the present application can be prepared as a quantum dot composition, and a quantum dot photoluminescent film can be prepared by photolithography. At this time, the viscosity of the quantum dot composition is, for example, 10 to 20 cp, and the surface tension is, for example, 25 to 40 mN / m, to obtain better light emission effect.

[0040] The core-shell structure quantum dots of the present application can be prepared as a quantum dot composition, and a quantum dot enhanced film can be prepared by a coating method. At this time, the pH value of the quantum dot composition is, for example, 6 to 10, and the viscosity is, for example, 10 to 2000 cp, to obtain better optical effects.

[0041] Some exemplary embodiments according to the present application are described in more detail below; however, the exemplary embodiments of the present application are not limited thereto.

[0042] Preparation Example 1-1

[0043] Synthesis of InP core:

[0044] 1.4 mmol of indium chloride was weighed and added to 20 mL of oleylamine. The temperature was evacuated at 120°C, switched to argon and heated to 190°C. Then, 2 mL of tris(diethylaminophosphine) was quickly added and reacted for 30 minutes to obtain an oleylamine solution of InP core, where the energy band gap of the InP core was 2.36 eV.

[0045] Preparation Example 1-2

[0046] Synthesis of InZnP core:

[0047] Weigh 1.4 mmol of indium chloride, 8.7 mmol of zinc iodide, and 20 mL of oleylamine, exhaust at 120°C, switch to argon, and raise the temperature to 190°C. Add 2 mL of tris(diethylaminophosphine) and react for 30 minutes to obtain an oleylamine solution of InZnP core, where the energy band gap of the InZnP core is 2.36 eV.

[0048] Preparation Examples 1-3

[0049] Synthesis of CdSe core:

[0050] Weigh 10 mmol of cadmium acetate dihydrate, 300 mmol of oleic acid, and 158 g of octadecene, exhaust at 120°C, switch to argon, and raise the temperature to 260°C. Add 10 mmol of selenium trioctylphosphine solution and react for 10 minutes to obtain an oleic acid solution of CdSe core, where the energy band gap of the CdSe core is 1.7 eV.

[0051] Preparation Examples 1-4

[0052] Synthesis of CdGaSe core:

[0053] Weigh 10 mmol of cadmium acetate dihydrate, 300 mmol of oleic acid, 5 mol of gallium acetylacetonate, and 158 g of octadecene, exhaust at 120°C, switch to argon, and raise the temperature to 260°C. Add 4 mmol of selenium in trioctylphosphine solution and react for 10 minutes to obtain an octadecene solution of CdGaSe core, where the band gap of the CdGaSe core is 2.73 eV.

[0054] Example 1

[0055] Synthesis of InP / GaInSe / ZnS:

[0056] To the oleylamine solution of the InP core of Preparation Example 1-1, 20 mL of 0.2 M gallium chloride oleylamine solution, 3 mL of 2 M selenium trioctylphosphine solution, and 2 mL of 0.2 M indium chloride oleylamine solution were simultaneously added dropwise and reacted for 30 minutes; after heating to 300°C, 20 mmol of zinc stearate was added and reacted for 20 minutes, and then 15 mL of n-dodecanethiol was added dropwise to form InP / GaInSe / ZnS core-shell structure quantum dots.

[0057] Among them, the energy band gap of the light-absorbing material GaInSe is 2.6eV, and the molar absorption coefficient is 5.5×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 20wt%.

[0058] Example 2

[0059] Synthesis of InZnP / ZnGaSe / ZnS:

[0060] To the oleylamine solution of the InZnP core of Preparation Example 1-2, 20 mL of 0.2 M gallium chloride oleylamine solution and 3 mL of 2 M selenium trioctylphosphine solution were simultaneously added dropwise, and the reaction was carried out for 30 minutes; after heating to 300°C, 20 mmol of zinc stearate was added, the reaction was carried out for 20 minutes, and then 15 mL of 2 M sulfur trioctylphosphine solution was added dropwise to form InZnP / ZnGaSe / ZnS core-shell structure quantum dots.

[0061] Among them, the energy band gap of the light-absorbing material ZnGaSe is 2.3eV, and the molar absorption coefficient is 2×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 25wt%.

[0062] Example 3

[0063] Synthesis of CdSe / CdGaS / ZnS:

[0064] The oleic acid solution of the CdSe core obtained in Preparation Example 1-3 was heated to 300°C, and simultaneously 2 mL of a 1 M sulfur trioctylphosphine solution, 1 mL of a 0.2 M cadmium oleate, and 20 mL of a 0.2 M gallium chloride oleylamine solution were added dropwise, 10 mmol of zinc stearate was added, and 15 mL of n-dodecyl mercaptan was added dropwise to form CdSe / CdGaS / ZnS core-shell structure quantum dots.

[0065] Among them, the energy band gap of the light-absorbing material CdGaS is 2.1eV, and the molar absorption coefficient is 5.5×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 20wt%.

[0066] Example 4

[0067] Synthesis of InZnP / ZnGaSeS / ZnS:

[0068] To the oleylamine solution of the InZnP core of Preparation Example 1-2, 20 mL of 0.2 M gallium chloride oleylamine solution, 1 mL of 2 M selenium trioctylphosphine solution, and 1.5 mL of 2 M sulfur trioctylphosphine solution were simultaneously added dropwise and reacted for 30 minutes; then the temperature was raised to 300°C, 20 mmol of zinc stearate was added, the reaction was continued for 20 minutes, and 15 mL of 2 M sulfur trioctylphosphine solution was added dropwise to form InZnP / ZnGaSeS / ZnS core-shell structure quantum dots.

[0069] Among them, the energy band gap of the light-absorbing material ZnGaSeS is 2.2eV, and the molar absorption coefficient is 2.5×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 20wt%.

[0070] Example 5

[0071] Synthesis of InZnP / ZnCdGaSe / ZnS:

[0072] To the oleylamine solution of the InZnP core of Preparation Example 1-2, 20 mL of 0.2 M gallium chloride oleylamine solution, 1 mL of 2 M selenium trioctylphosphine solution, and 15 mL of 0.2 M cadmium oleate were simultaneously added dropwise and reacted for 30 minutes; after heating to 300°C, 20 mmol of zinc stearate was added and reacted for 20 minutes, and then 10 mL of sulfur tributylphosphine solution was added dropwise to form InZnP / ZnCdGaSe / ZnS core-shell structure quantum dots.

[0073] Among them, the energy band gap of the light-absorbing material ZnCdGaSe is 2.7eV, and the molar absorption coefficient is 6×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 21wt%.

[0074] Example 6

[0075] Synthesis of CdGaSe / ZnGaSe / ZnGaS:

[0076] To the octadecene solution of the CdGaSe core of Preparation Example 1-4, 20 mL of 0.2 M gallium chloride oleylamine solution and 3 mL of 2 M selenium trioctylphosphine solution were simultaneously added dropwise and reacted for 30 min; after heating to 300 ° C, 20 mmol of zinc oleate was added and reacted for 20 min, and then 5 mL of n-dodecanethiol was added dropwise to form CdGaSe / ZnGaSe / ZnGaS core-shell structure quantum dots.

[0077] Among them, the energy band gap of the light-absorbing material CdGaSe is 1.9eV, and the molar absorption coefficient is 5.2×10 5 L / mol.cm, the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 15wt%; the energy band gap of the light-absorbing material ZnGaSe is 2.3eV, and the molar absorption coefficient is 7×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 20wt%.

[0078] Example 7

[0079] Synthesis of CdGaSe / ZnCdGaSe / ZnS:

[0080] To the octadecene solution of the CdGaSe core of Preparation Example 1-4, 20 mL of 0.2 M gallium chloride oleylamine solution, 10 mL of 0.4 M zinc chloride oleylamine solution, 20 mL of 0.2 M gallium chloride oleylamine solution, and 3 mL of 2 M selenium trioctylphosphine solution were simultaneously added dropwise and reacted for 30 min; after heating to 300 ° C, 20 mmol of zinc oleate was added and reacted for 20 min, and then 5 mL of n-dodecanethiol was added dropwise to form CdGaSe / ZnCdGaSe / ZnS core-shell structure quantum dots.

[0081] Among them, the energy band gap of the light-absorbing material CdGaSe is 1.9eV, and the molar absorption coefficient is 5.2×10 5 L / mol.cm, the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 13wt%; the energy band gap of the light-absorbing material ZnCdGaSe is 2.5eV, and the molar absorption coefficient is 6×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 25wt%.

[0082] Example 8

[0083] Synthesis of InP / InS / ZnSeS / ZnS:

[0084] To the oleylamine solution of the InP core of Preparation Example 1-1, 20 mL of 0.2 M indium chloride oleylamine solution and 1 mL of 2 M sulfur trioctylphosphine solution were simultaneously added dropwise, and the reaction was carried out for 30 minutes; then the temperature was raised to 240°C, 10 mmol of zinc stearate was added, and 2 mL of 2 M selenium trioctylphosphine solution and 2 mL of 2 M sulfur trioctylphosphine solution were simultaneously added dropwise, and the reaction was carried out for 30 minutes. The temperature was raised to 300°C, 20 mmol of zinc stearate was added, the reaction was carried out for 20 minutes, and 10 mL of n-octyl mercaptan was then added dropwise to form InP / InS / ZnSeS / ZnS core-shell structure quantum dots.

[0085] Among them, the energy band gap of the light-absorbing material InS is 2.2eV, and the molar absorption coefficient is 3×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 16wt%.

[0086] Example 9

[0087] Synthesis of InP / GaSe / ZnSeS / ZnS:

[0088] To the oleylamine solution of the InP core of Preparation Example 1-1, 20 mL of 0.2 M gallium chloride oleylamine solution and 1 mL of 2 M selenium trioctylphosphine solution were simultaneously added dropwise, and the reaction was carried out for 30 min; then the temperature was raised to 240 ° C, 10 mmol of zinc stearate was added, and 2 mL of 2 M selenium trioctylphosphine solution and 2 mL of 2 M sulfur trioctylphosphine solution were added dropwise, and the reaction was carried out for 30 min. The temperature was raised to 300 ° C, 20 mmol of zinc stearate was added, and the reaction was carried out for 20 min. Then, 10 mL of n-octyl mercaptan was added dropwise to form InP / GaSe / ZnSeS / ZnS core-shell structure quantum dots. The TEM image of the core-shell structure quantum dots is shown as follows: Figure 1 As shown, it can be seen that the particle size of the core-shell structure quantum dots is about 8nm.

[0089] Among them, the energy band gap of the light-absorbing material GaSe is 2.2eV, and the molar absorption coefficient is 5×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 20wt%.

[0090] Example 10

[0091] Synthesis of InP / GaSe / ZnSeS / ZnS:

[0092] To the oleylamine solution of the InP core of Preparation Example 1-1, 20 mL of 0.2 M gallium oleate oleylamine and 1 mL of 2 M selenium trioctylphosphine solution were simultaneously added dropwise, and the reaction was carried out for 30 min; after heating to 240 ° C, 10 mmol of zinc stearate was added, and 2 mL of 2 M selenium trioctylphosphine solution and 2 mL of 2 M sulfur trioctylphosphine solution were added dropwise, and the reaction was carried out for 30 min. The temperature was raised to 300 ° C, 20 mmol of zinc stearate was added, and the reaction was carried out for 20 min. Then, 10 mL of n-octyl mercaptan was added dropwise to form InP / GaSe / ZnSeS / ZnS core-shell structure quantum dots. The TEM image of the core-shell structure quantum dots is shown as follows: Figure 2 As shown, it can be seen that the particle size of the core-shell structure quantum dots is about 9 nm.

[0093] Among them, the energy band gap of the light-absorbing material GaSe is 2.2eV and the absorption coefficient is 5×10 5 L / mol.cm, and the mass percentage of the light-absorbing material in the core-shell structure quantum dots is 25%.

[0094] Comparative Example 1

[0095] Synthesis of InZnP / ZnSeS / ZnS:

[0096] 2 mL of 2M selenium trioctylphosphine solution and 2 mL of 2M sulfur trioctylphosphine solution were added to the oleylamine solution of the InZnP core of Preparation Example 1-2. After heating to 300°C, 20 mmol of zinc stearate was added and reacted for 20 minutes. Then, 10 mL of sulfur tributylphosphine solution was added dropwise to form InZnP / ZnSeS / ZnS core-shell structure quantum dots.

[0097] Comparative Example 2

[0098] Synthesis of InP / ZnSeS / ZnS:

[0099] To the oleylamine solution of the InP core of Preparation Example 1-1, 2 mL of 2M selenium trioctylphosphine solution and 2 mL of 2M sulfur trioctylphosphine solution were added dropwise. After heating to 300°C, 20 mmol of zinc stearate was added and the mixture was reacted for 20 minutes. Then, 10 mL of sulfur tributylphosphine solution was added dropwise to form InP / ZnSeS / ZnS core-shell structure quantum dots.

[0100] Comparative Example 3

[0101] Synthesis of CdSe / ZnSeS / ZnS:

[0102] The oleic acid solution of the CdSe core obtained in Preparation Example 1-3 was heated to 300°C, 20 mmol of zinc stearate was added and reacted for 15 minutes, and 2 mL of 1 M sulfur trioctylphosphine solution and 2 mL of 1 M selenium trioctylphosphine solution were added dropwise. The reaction was continued for 10 minutes, 10 mmol of zinc stearate was added, and 15 mL of n-dodecyl mercaptan was added dropwise to form CdSe / ZnSeS / ZnS core-shell structure quantum dots.

[0103] Comparative Example 4

[0104] Synthesis of CdGaSe / ZnSeS / ZnS:

[0105] To the octadecene solution of the CdGaSe core of Preparation Example 1-4, 20 mmol of zinc stearate was added, 2 mL of a 1 M sulfur trioctylphosphine solution and 2 mL of a 1 M selenium trioctylphosphine solution were added dropwise, and the mixture was reacted for 10 min. 10 mmol of zinc stearate was added, and 15 mL of n-dodecyl mercaptan was added dropwise to form CdGaSe / ZnSeS / ZnS core-shell structure quantum dots.

[0106] In the examples and comparative examples of the present application, a PerkinElmer Lambda 650 spectrophotometer was used to measure the ultraviolet absorbance of the core-shell structure quantum dots, a Hatichi F4500 fluorescence spectrophotometer was used to obtain the fluorescence emission spectrum of the core-shell structure quantum dots and the absorption spectrum at an excitation wavelength of 450 nm, and a Tecnai G2 F20 transmission electron microscope was used to perform TEM characterization of the core-shell structure quantum dots.

[0107] The molar absorptivity, emission peak wavelength, half-peak width, external quantum efficiency (EQE) and quantum efficiency (QY) of the core-shell structure quantum dots of Examples 1-10 and Comparative Examples 1-4 were measured during preparation and 30 days later. The specific results are shown in Table 1.

[0108] Table 1 Optical performance parameters of core-shell quantum dots of Examples 1-10 and Comparative Examples 1-4

[0109]

[0110]

[0111] Figure 3 The comparative absorption spectra of the core-shell structure quantum dots in Example 9 and Comparative Example 2 show that the OD of the core-shell structure quantum dots in Example 9 is 450 Significantly higher than comparative example 2

[0112] As can be seen from Table 1, compared with Comparative Examples 1-4, the core-shell structure quantum dots of Examples 1-10 of the present application have high absorbance, high quantum yield, and strong photothermal stability at a wavelength of 450nm, which will effectively improve the optical performance and stability of the quantum dot products prepared by the core-shell structure quantum dots of the present application, and extend the service life of the quantum dot products.

[0113] Although the inventors have elaborated and enumerated the technical solutions of the present application in detail, it should be understood that it is obvious for those skilled in the art to modify and / or adapt the above embodiments or adopt equivalent alternatives, which cannot deviate from the essence of the spirit of the present application. The terms appearing in the present application are used to explain and understand the technical solutions of the present application and cannot constitute a limitation on the present application.

Claims

1. A core-shell quantum dot for photoluminescence, comprising a core, a first shell layer covering the core, and a second shell layer covering the first shell layer, characterized in that: The energy band gap of the first shell layer is between the energy band gap of the crystal core and the energy band gap of the second shell layer, the first shell layer comprises a light-absorbing material, and the molar absorption coefficient of the light-absorbing material is greater than 10 5 L / (mol·cm); the band gap of the light-absorbing material is 2.0~2.7 eV; the light-absorbing material is at least one of GaInS, GaInSe, ZnGaSe, ZnGaS, CdGaSe, CdGaS, ZnCdGaS, ZnCdGaSe, GaInSeS, ZnGaSeS, and CdGaSeS.

2. The core-shell structure quantum dots for photoluminescence according to claim 1, characterized in that: The energy band gap of the light absorbing material is not less than the energy band gap of the crystal core.

3. The core-shell structure quantum dots for photoluminescence according to claim 1, characterized in that: The energy band gap of the core-shell structure quantum dots is 2.0-3.6 eV.

4. The core-shell structured quantum dots for photoluminescence according to claim 1, characterized in that: The lattice mismatch of the core-shell structure quantum dots is less than 10%.

5. The core-shell structured quantum dots for photoluminescence according to claim 1, characterized in that: The mass percentage of the light absorbing material in the core-shell structure quantum dots is 7-50 wt %.

6. The core-shell structure quantum dots for photoluminescence according to claim 1, characterized in that: The melting point of the light absorbing material is not lower than the melting point of the crystal core.

7. A quantum dot product, characterized in that The invention comprises the core-shell structure quantum dots for photoluminescence according to any one of claims 1 to 6.

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