CN105977336A - Quantum dot infrared detection and display device and production method thereof - Google Patents

Abstract

The invention relates to a quantum dot infrared detection and display device and a preparation method thereof, belonging to the field of preparation of nanometer semiconductor materials and optoelectronic devices. The device comprises: a substrate, an anode, a hole blocking layer (also an electron transport layer), an infrared light sensitive layer, a light-emitting layer, an electron transport layer and a cathode; the device is composed of an anode, a hole blocking layer (also an electron transport layer), Infrared photosensitive layer, luminescent layer, electron transport layer and cathode are prepared by depositing on the substrate in turn by film growth method; the present invention reduces the number of film layers, has low manufacturing cost, is convenient for large-scale production, and the electron transport material The colloidal quantum dots wrapped in a three-dimensional network structure formed by the hole transport material can rapidly transport the electrons and holes generated by the quantum dots to the hole blocking layer and the light emitting layer respectively.

Description

A quantum dot infrared detection and display device and its preparation method

technical field

The invention relates to a quantum dot infrared detection and display device and a preparation method thereof, belonging to the field of preparation of nanometer semiconductor materials and optoelectronic devices.

Background technique

Infrared detection and imaging technology has very important practical value and is widely used in environmental monitoring, weather forecasting, astronomical observation and military fields. At present, the mainstream infrared detectors (or thermal imagers) can be divided into two types according to the working temperature: cooling type and uncooling type. Generally, cooling infrared detectors work at the temperature of liquid nitrogen, have high detection rate and low dark current, but their refrigeration equipment is large in size and high in manufacturing cost, which is not conducive to miniaturized design and production, and is generally used in the military field. Uncooled infrared detectors work at room temperature, and their detection performance is usually not as good as that of cooled infrared detectors (or thermal imaging cameras), but their manufacturing cost is lower than that of cooled infrared detectors, and they are often used in commercial fields. These two kinds of detectors (or thermal imagers) need detection elements to convert infrared signals into electrical signals, and then transmit the signals to the display device for display through the readout circuit. Due to the different materials of the readout circuit and the detection element, the two are usually packaged together through a flip-chip interconnection process. The success rate of flip-chip interconnection technology is not high, resulting in high cost of detectors.

In order to better solve this problem, optical up-conversion technology has attracted widespread attention and research as an alternative. Based on different structures and principles, optical upconverters can be divided into two categories: one type of device absorbs two or more photoelectrons through rare earth elements, and then converts them into shorter-wavelength light for emission; the other type of device It is to absorb and convert light waves into photogenerated carriers first, and then transport the carriers to the light-emitting layer through an external electric field, and emit light of the required wavelength by exciting the light-emitting layer. This kind of device can artificially design and select the wavelength of the excitation light. In order to facilitate the transport of carriers, multi-layer electron transport layers and hole transport layers are usually required. However, the multi-layer film structure increases the complexity of the device structure, reduces the success rate of device preparation, and also increases the manufacturing cost, the process is complicated, and it is difficult to produce on a large scale.

Contents of the invention

The purpose of the present invention is to provide a quantum dot infrared detection and display device and its preparation method. The device has a simple structure and is easy to manufacture. The detection unit and the display unit are integrated together, and the long-wave (infrared light) to Optical up-conversion of short-wave (visible light) and display of images.

The purpose of the present invention is achieved through the following technical solutions.

A quantum dot infrared detection and display device, comprising: a substrate, an anode, a hole blocking layer (also an electron transport layer), an infrared light sensitive layer, a light-emitting layer, an electron transport layer and a cathode; an anode, a hole blocking layer (also an electron transport layer) Transport layer), infrared photosensitive layer, light-emitting layer, electron transport layer and cathode are deposited on the substrate by the method of film layer growth in sequence; the infrared photosensitive layer is infrared colloidal quantum dots, infrared colloidal quantum dots and hole transport material Mixed, infrared colloidal quantum dots mixed with electron transport materials or infrared colloidal quantum dots mixed with hole transport materials and electron transport materials;

The infrared colloidal quantum dot is a colloidal quantum dot with strong absorption in the infrared light band;

The infrared colloidal quantum dots include: one or more of PbS, PbSe, PbS _x Se _1-x and PbTe.

The hole transport material includes: 1-bis[(two-4-tolylamino)phenyl]cyclohexane (TAPC), P3HT, N,N'-diphenyl-N,N'(2-naphthyl )-(1,1'-phenyl)-4,4'-diamino (NPB) and N,N'-diphenyl-N,N'-di(m-tolyl)benzidine (TPD) one or more.

The electron transport material includes: 2,9-dimethyl-4,7-diphenyl-phenanthroline (BCP), C ₆₀ , Graphene (Graphene), TiO ₂ , tris-(8-hydroxyquinoline ) one or more of aluminum (Alq ₃ ), ZnO and PCBM.

At least one electrode of the cathode or anode is transparent or translucent, and when the infrared incident light is incident from the direction of the substrate, a substrate that is transparent or translucent to the infrared light should be selected, and the electrode in the incident direction of the infrared light must be transparent or translucent .

The anode material includes: one of indium tin oxide (ITO), indium zinc oxide (IZO), aluminum tin oxide (ATO), aluminum zinc oxide (AZO) and carbon nanotubes.

The materials of the hole blocking layer (HBL) and the electron transport layer include: 2,9-dimethyl-4,7-diphenyl-phenanthroline (BCP), TiO ₂ , three-(8-hydroxyquinoline One or more of aluminum (Alq ₃ ), ZnO and PCBM.

The light-emitting layer includes: tri-(2-phenylpyridine) iridium (Ir(ppy) ₃ ), poly[2-methoxy, 5-(2'-B-hexyloxy)phenylene Vinyl](MEH-PPV), tris-(8-hydroxyquinoline)aluminum (Alq ₃ ) or bis[(4,6-difluorophenyl)-pyridine-N,C2]picolinyl iridium(III ) (FIrpic) in one or more.

The cathode material includes: Ag, Ga, Mg, Al, LiF/Al, indium zinc oxide (IZO), indium tin oxide (ITO), aluminum tin oxide (ATO) or aluminum zinc oxide (AZO) kind of.

The thickness of the hole blocking layer is 15nm-45nm.

The thickness of the infrared light sensitive layer is 20nm-60nm.

The thickness of the luminescent layer is 25nm-100nm.

The thickness of the electron transport layer is 10nm-60nm.

The three-dimensional network structure formed by the electron transport material and the hole transport material in the infrared sensitive layer can quickly transport the electrons and holes generated by the quantum dots to the hole blocking layer and the light emitting layer respectively;

The substrate is flat glass, organic plastic, germanium wafer, silicon wafer, zinc sulfide, zinc selenide, chalcogenide glass and other materials;

A method for preparing a quantum dot infrared detection and display device, the specific steps are as follows:

1. Anode preparation: On a clean substrate, the anode material is plated on the surface of the substrate by magnetron sputtering or vacuum evaporation.

2. Preparation of the hole transport layer: the hole transport material is grown on the surface of the anode by vacuum evaporation and coating.

3. Preparation of the infrared light sensitive layer: on the surface of the hole transport layer, the infrared sensitive material solution is coated on the hole blocking layer, and the infrared light sensitive layer is formed after drying.

4. Preparation of the luminescent layer: according to the required luminescent wavelength, select a suitable luminescent material, and vacuum evaporate the luminescent layer onto the surface of the infrared light-sensitive layer.

5. Preparation of the electron transport layer: the electron transport material is grown on the surface of the light-emitting layer by vacuum evaporation.

6. Cathode preparation: the cathode material is evaporated on the surface of the electron transport layer by vacuum evaporation.

The preparation method of the infrared light-sensitive material solution is: according to the characteristics of the infrared colloidal quantum dots, electron transport materials and hole transport materials, respectively dispersing the infrared colloidal quantum dots, electron transport materials and hole transport materials into the same organic solvent , or respectively dispersed in different organic solvents that can be miscible to form different organic solutions. Then these solutions are mixed and fully stirred to form an infrared light sensitive material solution, wherein the mass ratio of infrared colloidal quantum dots is not less than 40%.

Beneficial effect

1. A quantum dot infrared detection and display device of the present invention uses a single layer of infrared quantum dots or one or more of infrared quantum dots mixed with hole transport materials and electron transport materials as an infrared sensitive layer. Realization: the number of layers of the film is reduced, the manufacturing cost is low, and the three-dimensional network structure formed by the electron transport material and the hole transport material wraps the colloidal quantum dots, which can quickly transfer the electrons and holes generated by the quantum dots to the hole blocking layer and the light emitting layer respectively. transmission.

2. A quantum dot infrared detection and display device of the present invention, when infrared light is incident from the substrate, the substrate used must be able to pass through the infrared light band; if the substrate material can cut off visible light, the concealment of the night vision device can be enhanced; If the substrate material is transparent to both the infrared and visible light bands, imaging can be performed on both the front and rear sides of the device simultaneously. When the device structure uses a reflective structure, the intensity of visible light can be enhanced.

3. The preparation method of a quantum dot infrared detection and display device of the present invention has simple production process requirements, low manufacturing cost, high device preparation success rate, and is convenient for large-scale production.

Description of drawings

Figure 1 is a schematic diagram of the transmission structure of the device;

Fig. 2 is the cathodic reflective structure schematic diagram of device;

Fig. 3 is a schematic diagram of the anode reflective structure of the device;

4 is a schematic diagram of the energy level structure of the first device;

Fig. 5 is the schematic diagram of the energy level structure of the second device;

Fig. 6 is a schematic diagram of the energy level structure of the third device.

detailed description

In order to make the purpose, content and advantages of the present invention clearer, the specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Example 1

As shown in Figures 1 and 4, a quantum dot infrared detection and display device sequentially includes a substrate, an anode, a hole blocking layer, an infrared photosensitive layer, a light-emitting layer, an electron transport layer, and a cathode; the substrate is glass, and the anode is ITO, 15nm-thick ZnO layer for the hole-blocking layer, 60nm-thick PbSe quantum dots for the infrared light-sensitive layer, a mixture of PCBM and P3HT, and the light-emitting layer (30nm) is 5% Ir(ppy) ₃ and 95% CBP The mixed layer, the electron transport layer is a 10nm thick BCP layer, and the cathode is an ATO electrode. Directly use the glass substrate with ITO film produced by magnetron sputtering, and treat the ITO layer with ultraviolet ozone to obtain a fresh ITO surface. Then, on the surface of the ITO electrode, 2-methoxyethanol sol of zinc acetate dihydrate was coated, dried at room temperature for 15 minutes, and then heated to 300°C in air for 5 minutes to form a ZnO layer. The infrared light sensitive material solution is coated on the ZnO surface and dried at room temperature for 10 minutes to form an infrared light sensitive layer. Finally, it is sent to a vacuum coating machine, where the luminescent layer, electron transport layer and electrodes are evaporated in sequence to form a quantum dot infrared detection and display device. When 980nm infrared light is used to irradiate the device as shown in Figure 1, the device will emit 510nm green light at an operating voltage of 12V-30V. Both the substrate and the electrodes of the device are transparent, and images can be formed on both sides of the device, and the method adopted by the device is equivalent to sequentially preparing the PCBM electron transport layer, the PbSe quantum dot infrared absorption layer and the P3HT hole transport layer. Under the same process conditions, this method reduces the process of film layer preparation at least twice, reduces the preparation time by more than 4 hours, and increases the success rate of device fabrication from 47% to 81%. At the same time, under the same luminous brightness, the working voltage drops by 3V -5V.

The preparation method of the infrared light-sensitive material solution is to disperse PbSe quantum dots, PCBM and P3HT into chlorobenzene to form three kinds of solutions respectively, and mix these three solutions according to the ratio of 2:1:1 to form the infrared light-sensitive material solution.

Example 2

As shown in Figure 2 and Figure 5, a quantum dot infrared detection and display device, including the substrate is infrared and visible light transparent glass, the anode is IZO, the hole blocking layer is a 20nm thick BCP layer, and the infrared light sensitive layer is Mixed layer of 45nm thick PbS quantum dots and graphene (Graphene), light emitting layer (25nm) is a mixture layer of 7% Ir(ppy) ₃ and 93% CBP, electron transport layer is 20nm thick BCP layer, cathode for the Al electrode. IZO thin-film electrodes were produced on glass substrates using magnetron sputtering. On the fresh IZO thin film electrode surface, a BCP hole blocking layer was evaporated using a vacuum coating machine. The infrared light-sensitive material solution is coated on the surface of the BCP and dried at room temperature for 15 minutes to form an infrared light-sensitive layer. Finally, it is sent to a vacuum coating machine, where the luminescent layer, electron transport layer and electrodes are evaporated in sequence to form a quantum dot infrared detection and display device. When 850nm infrared light is used to irradiate the device as shown in the figure, the device will emit 510nm green light under the working voltage of 11V-24V. The base of the device is transparent, and the aluminum electrode is used as the cathode, which can enhance the visible light imaging effect through the reflection of the aluminum electrode, and the method adopted by the device is equivalent to sequentially preparing a graphene (Graphene) electron transport layer and a PbS quantum dot infrared absorption layer. Under the same process conditions, this method reduces the process of film layer preparation at least once, the preparation time is reduced by more than 2 hours, and the success rate of device production is increased from 53% to 76%. At the same time, under the same luminous brightness, the operating voltage drops by 2V 6V.

The preparation method of infrared photosensitive material solution is to disperse PbS quantum dots into n-octane and disperse graphene oxide into ethylene glycol to form two kinds of solutions, and mix these two solutions according to the ratio of 3:1 to form an infrared photosensitive material solution. Light-sensitive material solution. The graphene oxide in the solution turns into graphene during drying to form a film.

Example 3

As shown in Figure 3 and Figure 6, a quantum dot infrared detection and display device sequentially includes a silicon wafer as the substrate, an ITO layer as the anode, a 45nm-thick _TiO2 hole blocking layer, and a 45nm-thick infrared photosensitive layer. The mixture layer of PbS quantum dots and PbSe quantum dots with PCBM and P3HT, the light-emitting layer is an 80nm thick MEH-PPV layer, the electron transport layer is a 60nm thick BCP layer, and the cathode is an ATO electrode. ITO thin film electrodes were grown on silicon wafers by magnetron sputtering. TiO ₂ quantum dots were coated on the surface of clean ITO thin film electrodes and dried at room temperature for 8 min to form a hole blocking layer. After coating the infrared light-sensitive material solution on the surface of TiO ₂ , dry it at room temperature for 12 minutes to form an infrared light-sensitive layer. Finally, in the vacuum coating machine, the luminescent layer, the electron transport layer and the electrodes are evaporated in sequence to form a quantum dot infrared detection and display device. When 850nm infrared light is used to irradiate the device as shown in the figure, the device will emit 630nm red light under the working voltage of 20V-27V. The substrate of this device is opaque to the infrared light of the corresponding band and the emitted visible light, but the electrode is transparent, the infrared photocathode is incident, and the visible light is emitted from the cathode after being enhanced by the reflection of the anode, and the method adopted by this device is equivalent to sequentially preparing PCBM electron transmission Layer, PbSe quantum dot infrared absorption layer, PbS quantum dot infrared absorption layer and P3HT hole transport layer. Under the same process conditions, the method reduces the film layer preparation process at least three times, the preparation time is reduced by more than 5 hours, the success rate of device production is increased from 48% to 87%, and at the same time, the working voltage is reduced by 4V-7V under the same brightness.

The preparation method of infrared light-sensitive material solution is to disperse PbS quantum dots and PbSe quantum dots with PCBM and P3HT in chlorobenzene respectively to form four kinds of solutions, and mix these four kinds of solutions according to the ratio of 2:1:1:1 to form infrared Light-sensitive material solution.

Example 4

As shown in Figure 1 and Figure 6, a quantum dot infrared detection and display device, sequentially includes the substrate as zinc sulfide, the anode as the ITO layer, the hole blocking layer as 45nm thick TiO ₂ , the infrared light sensitive layer as 45nm thick TiO 2 The mixture layer of PbS quantum dots and PbSe quantum dots with PCBM and P3HT, the light-emitting layer is an 80nm thick MEH-PPV layer, the electron transport layer is a 60nm thick BCP layer, and the cathode is an ATO electrode. The preparation method is shown in Example 3. The base of the device is transparent to infrared light and opaque to visible light, the infrared light is incident from the base, and the visible light emitted by the light-emitting layer is emitted from the cathode, so the concealment effect is better.

Claims (10)

1. a quantum dot infrared acquisition and display device, it is characterised in that: including: substrate, anode, sky Barrier layer, cave, infrared light sensitive layer, luminescent layer, electron transfer layer and negative electrode；Anode, hole blocking layer, Infrared light sensitive layer, luminescent layer, electron transfer layer and negative electrode pass sequentially through the method for coating growth and are deposited on base At at the end；Described infrared light sensitive layer is infrared Colloidal Quantum Dots, infrared Colloidal Quantum Dots and hole mobile material Mix, infrared Colloidal Quantum Dots and electron transport material mix or infrared Colloidal Quantum Dots and hole Transmission material and electron transport material mix.

2. a kind of quantum dot infrared acquisition as claimed in claim 1 and display device, it is characterised in that: institute Stating infrared Colloidal Quantum Dots is to have the relatively strong Colloidal Quantum Dots absorbed at infrared band.

3. a kind of quantum dot infrared acquisition as claimed in claim 1 or 2 and display device, it is characterised in that: Described infrared Colloidal Quantum Dots includes: PbS, PbSe, PbS_xSe_1-xWith one or more in PbTe.

4. a kind of quantum dot infrared acquisition as claimed in claim 1 and display device, it is characterised in that: institute State hole mobile material to include: 1-double [(two-4-toluidinos) phenyl] hexamethylene, P3HT, N, N '- Diphenyl-N, N ' (2-naphthyl)-(1,1 '-phenyl)-4,4 '-two amidos and N, N '-diphenyl-N, N '- In two (tolyl) benzidine one or more；Described electron transport material includes: 2,9-dimethyl-4, 7-diphenyl-phenanthroline, C₆₀, Graphene, TiO₂, three-(8-hydroxyquinoline) aluminum, in ZnO and PCBM One or more.

5. a kind of quantum dot infrared acquisition as claimed in claim 1 and display device, it is characterised in that: institute State negative electrode or at least one electrode of anode is transparent or semitransparent, and when infrared incident illumination is incident from substrate direction Time, should select infrared light transparent or translucent substrate, the electrode of infrared light incident direction is necessary for simultaneously Transparent or semitransparent.

6. a kind of quantum dot infrared acquisition as claimed in claim 1 and display device, it is characterised in that: institute State anode material to include: tin-oxide, indium-zinc oxide, aluminum tin-oxide, aluminum zinc oxide and carbon are received One in mitron；The material of described hole blocking layer and electron transfer layer includes: 2,9-dimethyl-4, 7-diphenyl-phenanthroline, TiO₂, three-(8-hydroxyquinoline) aluminum, one or more in ZnO and PCBM； Described luminescent layer includes: three-(2-phenylpyridine) closes iridium, poly-[2-methoxyl group, 5-(2 '-second class-hexyloxy) Phenylene vinylidene], three-(8-hydroxyquinoline) aluminum or double [(4,6-difluorophenyl)-pyridine-N, C2] pyrrole Pyridine formyl closes one or more in iridium (III)；Described cathode material includes: Ag, Ga, Mg, Al, LiF/Al, One in indium-zinc oxide, tin-oxide, aluminum tin-oxide or aluminum zinc oxide；Described substrate is flat The materials such as glass sheet, organic plastics, germanium wafer, silicon chip, zinc sulfide, zinc selenide, chalcogenide glass.

7. a kind of quantum dot infrared acquisition as described in claim 1 or 6 and display device, it is characterised in that: Described hole barrier layer thickness is 15nm-45nm；Described infrared light sensitive layer thickness is 20nm-60nm； Described light emitting layer thickness is 25nm-100nm；Described electric transmission layer thickness is 10nm-60nm.

8. a quantum dot infrared acquisition and the preparation method of display device, it is characterised in that: concrete steps are such as Under:

1. prepared by anode: plated by anode material by the method for magnetron sputtering or vacuum evaporation in clean substrate System is at substrate surface；

2. the preparation of hole transmission layer: anode surface by vacuum evaporation, coating method by hole transport material Material is grown in anode surface；

3. the preparation of infrared light sensitive layer: on hole transmission layer surface, infrared-sensitive material solution is coated in sky On barrier layer, cave, dried formation infrared light sensitive layer；

4. the preparation of luminescent layer: according to the wavelength of required luminescence, selects suitable luminescent material, uses vacuum to steam The method of plating, is deposited with infrared light sensitive layer surface by luminescent layer；

5. the preparation of electron transfer layer: electron transport material is grown in luminescent layer table by the method for vacuum evaporation Face；

6. prepared by negative electrode: be deposited with on the surface of electron transfer layer by the method for vacuum evaporation by cathode material.

A kind of quantum dot infrared acquisition the most as claimed in claim 8 and the preparation method of display device, it is special Levy and be: the preparation method of described infrared light sensitive material solution is: according to infrared Colloidal Quantum Dots, electronics Transmission material and the feature of hole mobile material, respectively by infrared Colloidal Quantum Dots, electron transport material and sky Hole transport materials is distributed to same organic solvent, or is distributed to the different organic solvent that can dissolve each other respectively In, form different organic solution；Then infrared light is formed after these solution being mixed and are sufficiently stirred for sensitive Material solution.

A kind of quantum dot infrared acquisition the most as claimed in claim 8 or 9 and the preparation method of display device, It is characterized in that: shared by described infrared Colloidal Quantum Dots, the mass ratio of infrared light sensitive material solution is not less than 40%.