A preparation method of a metal nanocluster electroluminescent device based on host-guest

Abstract

The application relates to the technical field of chemistry, and discloses a preparation method of a metal nanocluster electroluminescent device based on host-guest, which comprises the following steps: adding a gold alkyne complex AuC2R (R=C6H 11 0) and crystalline 1,4-(PPh2)2C6H4 into 10 ml of a dichloromethane solution with chromatographic purity and stirring at room temperature, and then adding Cu(NCMe)4PF6 dissolved in 5 ml of a dichloromethane solution with chromatographic purity and stirring, the application proposes a method for preparing a metal nanocluster LED by using metal nanoclusters Au6Cu2 and host materials mCP and PO-T2T to construct a host-guest material system, the introduction of the host materials not only ensures the uniformity of the metal nanocluster film, but also significantly improves the light-emitting intensity of the film, and the photoluminescence quantum yield (PLQY) is increased from 10.19% to 38.59%.

Description

Technical Field

[0001] The present invention relates to the field of chemical technology, and in particular to a method for preparing a host-guest based metal nanocluster electroluminescent device. Background Art

[0002] Metal nanoclusters (NCs) combine the advantages of organic molecules and inorganic nanomaterials, with the excellent properties of low cost, low toxicity and simple fabrication process. Their excellent optical properties make them candidates for light-emitting diode (LED) applications. Their organic-inorganic hybrid characteristics make metal nanoclusters well soluble in most organic solvents, making them suitable for solvent-based fabrication. However, due to their unique nanoscale size, they often lead to severe phase disorder, resulting in low luminescence efficiency. The low device efficiency is mainly due to the strong interfacial quenching caused by the unevenness of the film, and the resulting Joule heating will seriously limit the peak efficiency and service life of the device.

[0003] Therefore, achieving smoothness in metal nanocluster films while maintaining their luminescence intensity is a key challenge for metal nanocluster electroluminescence (EL) applications. Currently, the field primarily focuses on modifying the metal nanocluster emitter itself. However, the complex synthesis process and processing conditions have led to a sharp increase in the cost and energy consumption of metal nanocluster light-emitting diodes, which in turn has limited the application of existing metal nanoclusters. A broadly applicable device design strategy is urgently needed to promote the EL application of metal nanoclusters.

[0004] To address these technical challenges, it's essential to utilize existing, low-cost materials and, using simple processes, produce metal nanoclusters that meet the production requirements of light-emitting diodes. By incorporating common organic materials into the host-guest system, the team achieved both high luminescence intensity and reduced surface roughness in the metal nanocluster film, further improving raw material utilization and strictly controlling both time and financial costs, ultimately resolving practical production challenges. Summary of the Invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for preparing a host-guest metal nanocluster electroluminescent device.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a host-guest metal nanocluster electroluminescent device comprises the following steps:

[0008] Step 1: Prepare the gold alkynyl complex AuC2R (R = C6H 110), crystalline 1,4-(PPh2)2C6H4 was added to 10 ml of chromatographically pure dichloromethane solution and stirred at room temperature for 30 min, followed by the addition of Cu(NCMe)4PF6 dissolved in 5 ml of chromatographically pure dichloromethane solution and stirring for 15 min to obtain a bright yellow solution;

[0009] Step 2: Place the solution obtained in step 1 in a fume hood at 5°C to evaporate the solvent for crystallization. After standing for 72 hours, yellow needle-shaped Au6Cu2 crystals are obtained.

[0010] Step 3: Dissolve the crystals obtained in step 2 in chromatographically pure dichloromethane and add powdered host materials mCP and PO-T2T into the solution. Stir for 10 minutes to obtain a uniformly distributed host-guest mixed solution.

[0011] Step 4: Preliminary preparation of metal nanocluster LEDs based on host-guest material systems;

[0012] The ITO conductive glass was cleaned with soap, deionized water, ethanol, chloroform, acetone, and isopropyl alcohol in sequence, and then treated with UV-ozone.

[0013] A PEDOT:PSS solution (Baytron PVP Al4083) was spin-coated onto the treated ITO glass through a filter head and then annealed to form a hole injection layer. The substrate was then transferred to a glove box filled with N2 gas.

[0014] Spin-coat the host-guest mixed solution prepared in step 3 onto the PEDOT:PSS layer as the light-emitting layer;

[0015] Step 5: The product obtained in step 4 is finally transferred into a vacuum chamber, and TPBi, LiF and Al layers are sequentially deposited by thermal evaporation, wherein the TPBi layer serves as an electron transport layer and a hole blocking layer, and the LiF and Al layers serve as top electrodes; thus, a metal nanocluster electroluminescent device based on a host-guest material system is obtained.

[0016] Preferably, in step 1, the gold alkynyl complex AuC2R (R = C6H 11 0), the masses of crystalline 1,4-(PPh2)2C6H4 and Cu(NCMe)4PF6 are 96 mg, 69 mg and 38 mg respectively.

[0017] Preferably, the concentrations of Au6Cu2 crystals and powdered host materials mCP and PO-T2T are 1 mg / ml, 0.75 mg / ml and 0.75 mg / ml respectively.

[0018] Preferably, in step 3, the stirring speed is 600-1000 r / min.

[0019] Preferably, in step 4, the rotation speed of the spin-coating PeDOT:PSS is 2000 r / min, and the rotation speed of the host-guest mixed solution spin-coated on the PeDOT:PSS layer is 2000 r / min.

[0020] Preferably, in step 3, the annealing treatment of the PeDOT:PSS is specifically annealing at a temperature of 170℃ for 30 min.

[0021] Preferably, in step 5, the evaporation speed of TPBi and LiF is 0.1 nm / s, and the evaporation speed of Al is 1 nm / s.

[0022] The beneficial effects of the present application are:

[0023] The present application provides a method for preparing a metal nanocluster LED by using metal nanocluster Au6Cu2 and host material mCP, PO-T2T to construct a host-guest material system. The introduction of the host material not only ensures the uniformity of the metal nanocluster film, but also significantly improves the luminescence intensity of the film. The photoluminescence quantum yield (PLQY) is increased from 10.19% to 38.59%. Further, the host-guest material system is used as an emission layer to prepare a pure yellow metal nanocluster LED with an electroluminescence (EL) wavelength of 570 nm. The device has a high brightness of 4932 cd m -2 and a high external quantum efficiency (EQE) of 5.29%. At the same time, the balanced carrier transport environment in the device greatly improves the spectral stability of the device.

[0024] The method for preparing a metal nanocluster electroluminescent device based on a host-guest material system provided by the present application has the advantages of simple operation, short time consumption, low energy consumption, and simple process requirements. The metal nanocluster film prepared by the method has low surface roughness, high photoluminescence quantum yield, high color purity, and good device stability. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The overall structural formula of the selected metal nanocluster Au6Cu2 and the metal core-ligand structure thereof are shown in the following table:

[0026] Figure 2 The absorption spectrum, solution-state photoluminescence spectrum, and film-state photoluminescence spectrum of the selected metal nanocluster Au6Cu2 are shown in the following table:

[0027] Figure 3 The photoluminescence quantum yields of the unoptimized and optimized metal nanocluster films are shown in the following table:

[0028] Figure 4 The atomic force microscope images (AFM) of the unoptimized and optimized metal nanocluster films are shown in the following table:

[0029] Figure 5 Laser scanning confocal microscopy (LSCM) images of unoptimized and optimized metal nanocluster films;

[0030] Figure 6 Ultraviolet photoelectron spectroscopy (UPS) of the selected metal nanoclusters Au6Cu2;

[0031] Figure 7 The brightness-voltage-current density curves of the unoptimized and optimized metal nanocluster LEDs;

[0032] Figure 8 The external quantum efficiency, current power, power efficiency-brightness curves of the unoptimized and optimized metal nanocluster LEDs;

[0033] Figure 9 Transient photoluminescence spectra (TRPL) of unoptimized and optimized metal nanocluster films;

[0034] Figure 10 To optimize the electrospectral stability of metal nanocluster LEDs at a voltage of 4-7.3V. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] In one embodiment, a method for preparing a high-efficiency yellow-emitting metal nanocluster LED by combining metal nanoclusters Au6Cu2 with host materials mCP and PO-T2T is provided. The method comprises the following steps:

[0037] 1) 96 mg of gold alkynyl complex AuC2R (R = C6H 11 0), 69 mg of crystalline 1,4-(PPh2)2C6H4 was added to 10 ml of chromatographically pure dichloromethane solution and stirred at room temperature for 30 min, followed by the addition of 38 mg of Cu(NCMe)4PF6 dissolved in 5 ml of chromatographically pure dichloromethane solution and stirring for 15 min to obtain a bright yellow solution.

[0038] 2) Place the solution in 1 in a fume hood at 5°C to evaporate the solvent for crystallization. After standing for 72 hours, yellow needle-shaped Au6Cu2 crystals are obtained.

[0039] 3) Under nitrogen atmosphere, dissolve 1 mg of Au6Cu2 crystals obtained in step 2 in 1 ml of chromatographically pure dichloromethane, add 0.75 mg of mCP powder and 0.75 mg of PO-T2T powder to the solution, and stir vigorously for 10 min to obtain a uniform host-guest mixed solution;

[0040] 4) Preliminary preparation of metal nanocluster LEDs based on host-guest material systems;

[0041] The ITO conductive glass was carefully cleaned with soap, deionized water, ethanol, chloroform, acetone and isopropyl alcohol, and then treated with UV-ozone.

[0042] A PEDOT:PSS solution (Baytron PVP Al4083) was spin-coated onto the treated ITO glass through a filter head and then annealed to form a hole injection layer. The substrate was then transferred to a glove box filled with N2 gas.

[0043] Spin-coat the host-guest mixed solution prepared in step 3 onto the PEDOT:PSS layer as the light-emitting layer;

[0044] 5) The product obtained in step 4 is finally transferred to a vacuum chamber, and TPBi, LiF, and Al layers are sequentially deposited by thermal evaporation, wherein the TPBi and LiF layers are deposited at a rate of 0.1 nm / s, and the Al layer is deposited at a rate of 1 nm / s; thereby, a metal nanocluster LED based on a host-guest material system is obtained.

[0045] like Figure 1 As shown in Figure 2, the metal nanoclusters Au6Cu2 consist of an internal metal core and external organic ligands. Figure 2 As shown in Figure 2, the synthesized crystals have the characteristic absorption and emission peaks of metal nanoclusters, ensuring the high purity of the material. Figure 3 As shown in Figure 2, the photoluminescence quantum yield of the metal nanocluster film after optimization of the host-guest material system is significantly improved. Figure 4 As shown in Figure 2, the unoptimized metal nanocluster film has a high roughness, while the roughness of the metal nanocluster film optimized with the host-guest material system is significantly reduced. Figure 5 As shown in the figure, laser scanning confocal microscopy was used to measure the luminescence intensity and uniformity of a large area of ​​the film. The results showed that the metal nanocluster film after the host-guest material system was optimized had high luminescence intensity and uniformity, which was consistent with the photoluminescence quantum yield measurement results. Figure 6 As shown in Figure 2, unoptimized metal nanoclusters and metal nanoclusters optimized by the host-guest material system were used as light-emitting layers to prepare LEDs. Figure 7 , as shown in Figure 8, the optimized LED achieves 4932cd / m 2The maximum brightness and peak external quantum efficiency of 5.29%. Figure 9 As shown in Figure 2, the emission lifetime of the film is significantly enhanced after modification, which is consistent with the device performance results. Figure 10 As shown, the optimized device can achieve stable yellow light emission at 4-7V.

[0046] The present invention proposes a method for preparing metal nanocluster LEDs by constructing a host-guest material system using metal nanoclusters Au6Cu2 and host materials mCP and PO-T2T. The introduction of the host material not only ensures the uniformity of the metal nanocluster film but also significantly improves the luminescence intensity of the film, increasing the photoluminescence quantum yield (PLQY) from 10.19% to 38.59%. Furthermore, using this host-guest material system as the emission layer, a pure yellow metal nanocluster LED with an electroluminescence (EL) wavelength of 570nm was prepared. The device has a luminous flux of 4932cd m -2 The device achieves high brightness and a high external quantum yield (EQE) of 5.29%. At the same time, the balanced carrier transport environment in the device greatly improves the spectral stability of the device.

[0047] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a host-guest metal nanocluster electroluminescent device, characterized in that: The following steps are involved: Step 1: Prepare the gold alkynyl complex AuC2R (R = C6H 11 0), crystalline 1,4-(PPh2)2C6H4 was added to 10 ml of chromatographically pure dichloromethane solution and stirred at room temperature for 30 min, followed by the addition of Cu(NCMe)4PF6 dissolved in 5 ml of chromatographically pure dichloromethane solution and stirring for 15 min to obtain a bright yellow solution; Step 2: Place the solution obtained in step 1 in a fume hood at 5°C to evaporate the solvent for crystallization. After standing for 72 hours, yellow needle-shaped Au6Cu2 crystals are obtained. Step 3: Dissolve the crystals obtained in step 2 in chromatographically pure dichloromethane and add powdered host materials mCP and PO-T2T into the solution. Stir for 10 minutes to obtain a uniformly distributed host-guest mixed solution. Step 4: Preliminary preparation of metal nanocluster LEDs based on host-guest material systems; The ITO conductive glass was cleaned with soap, deionized water, ethanol, chloroform, acetone, and isopropyl alcohol in sequence, and then treated with UV-ozone. PEDOT:PSS solution (Baytron PVP Al4083) was spin-coated on the treated ITO glass through a filter head, followed by annealing to obtain a hole injection layer; The substrate was then transferred into a glove box filled with N2 gas; Spin-coat the host-guest mixed solution prepared in step 3 onto the PEDOT:PSS layer as the light-emitting layer; Step 5: The product obtained in step 4 is finally transferred into a vacuum chamber, and TPBi, LiF and Al layers are sequentially deposited by thermal evaporation, wherein the TPBi layer serves as an electron transport layer and a hole blocking layer, and the LiF and Al layers serve as top electrodes; thus, a metal nanocluster electroluminescent device based on a host-guest material system is obtained.

2. The method for preparing a host-guest metal nanocluster electroluminescent device according to claim 1, characterized in that: In step 1, the gold alkynyl complex AuC2R (R = C6H 11 0), the masses of crystalline 1,4-(PPh2)2C6H4 and Cu(NCMe)4PF6 are 96 mg, 69 mg and 38 mg respectively.

3. The method for preparing a host-guest metal nanocluster electroluminescent device according to claim 1, characterized in that: The concentrations of Au6Cu2 crystals and powdered host materials mCP and PO-T2T were 1 mg / ml, 0.75 mg / ml and 0.75 mg / ml respectively.

4. The method for preparing a host-guest metal nanocluster electroluminescent device according to claim 1, characterized in that: In step 3, the stirring speed is 600-1000 r / min.

5. The method for preparing a host-guest metal nanocluster electroluminescent device according to claim 2, characterized in that: In step 4, the rotation speed of the spin coating PeDOT:PSS is 2000 r / min, and the rotation speed of the host-guest mixed solution spin coating on the PeDOT:PSS layer is 2000 r / min.

6. The method for preparing a host-guest metal nanocluster electroluminescent device according to claim 2, characterized in that: In step 3, the PeDOT:PSS is annealed at a temperature of 170° C. for 30 minutes.

7. The method for preparing a host-guest metal nanocluster electroluminescent device according to claim 2, characterized in that: In step 5, the evaporation rate of TPBi and LiF is 0.1 nm / s, and the evaporation rate of Al is 1 nm / s.

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