CN112201759B - Solution processing serial quantum dot light-emitting diode based on doped connection layer and manufacturing method thereof - Google Patents
Solution processing serial quantum dot light-emitting diode based on doped connection layer and manufacturing method thereof Download PDFInfo
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Abstract
The invention belongs to the technical field of quantum dot light-emitting diodes, in particular to a solution processing series quantum dot light-emitting diode based on a doped connecting layer and a manufacturing method thereof, the series quantum dot light emitting diode is manufactured based on the manufacturing method and comprises a bottom device and a top device, the bottom device comprises a cathode, a first electron injection layer, a first quantum dot light-emitting layer, a first hole transport layer and a first hole injection layer which are sequentially stacked from bottom to top, the top end device comprises a second electron injection layer, a second quantum dot light emitting layer, a second hole transport layer, a second hole injection layer and an anode which are sequentially stacked from bottom to top, the first hole injection layer of the bottom device is stacked with the second electron injection layer of the top device, the first hole injection layer adopts PEDOT: PSS-GO solution, and the second electron injection layer is made of ZnMgO-containing solution. The invention provides an effective method for improving the performance of a quantum dot light-emitting diode processed by a solution.
Description
Technical Field
The invention belongs to the technical field of quantum dot light-emitting diodes, and particularly relates to a solution-processed series quantum dot light-emitting diode based on a doped connection layer and a manufacturing method thereof.
Background
The quantum dot belongs to one of new material-solution nanocrystalline. Solution nanocrystals have the dual properties of crystals and solutions, unlike other nanocrystal materials, quantum dots are based on semiconductor crystals. The size is between 1 and 100 nanometers, and each particle is a single crystal. The name of quantum dots is derived from the quantum confinement effect or quantum size effect of semiconductor nanocrystals. When the semiconductor crystal is small to the nanometer scale, different sizes can emit light with different colors. Semiconductor nanocrystals such as cadmium selenide emit blue light at 2 nm, red light at 8 nm, green, yellow, orange, and so on at intermediate sizes. The chemical components of the quantum dots can cover the whole visible region from blue light to red light in the luminescent color, and the color purity is high and continuously adjustable.
The quantum dot technology can be applied to the field of biological medical treatment, for example, different colors of quantum dots can be easily utilized to simultaneously detect various germs or pesticide residues. The LED lamp can also be applied to the technical field of lighting industry, has higher luminous efficiency and can save energy consumption compared with the traditional lighting technology. The method can also be applied to the technical field of display, and can improve the purity, the color saturation and the like of the display color.
Quantum Dot Light-Emitting diodes (QLEDs) are Light-Emitting diodes with Quantum Dot materials as Light-Emitting layers, and exhibit wide application prospects in the fields of future display and illumination, because colloidal Quantum dots as Light-Emitting layers have unique properties such as solution processability, good monochromaticity, adjustable Light-Emitting color, good stability, high Quantum yield and the like. As research work continues, various optimization schemes including optimization of quantum dots and charge transport materials, optimization of device structures, etc. have been proposed in order to obtain QLEDs with superior performance. The series structure device can work under lower current density, so the service life of the device can be effectively prolonged. In addition, the serial Quantum Dot Light-Emitting Diodes (TQLEDs) include two or more Light-Emitting units, and the Light-Emitting efficiency is multiplied. This all results in TQLEDs showing significant advantages.
In order to meet the requirements of low cost and large-area industrial production, and simultaneously, in order to be directly connected with an N-type transistor, reduce the lattice driving voltage of a device and stabilize the device, a great deal of work is devoted to research and development of a high-performance solution processing inversion type TQLED. In the structural device, how to realize effective connection of two light-emitting units, and preparing a solution processing connection layer with good charge injection and charge generation electrical properties is the most important link for carrying out work. The prior art discloses a solution processing inverted green TQLED, wherein a solution processing connection layer adopts a heterojunction PEDOT: PSS/ZnMgO consisting of PEDOT: PSS with good conductivity and ZnMgO with good electron mobility, but the deposition of aqueous PEDOT: PSS on an organic layer is difficult, which inevitably influences the effective film formation of the organic layer and further influences the effective deposition of subsequent layers. In addition, PEDOT, PSS, has a large hole injection barrier between the organic hole transport layer, which can cause hole injection difficulties and make electron and hole injection unbalanced. These disadvantages greatly limit the application of the solution processed connection layer in the TQLED and also limit the improvement of the TQLED performance.
Disclosure of Invention
One of the objectives of the present invention is to provide a solution processed serial quantum dot light emitting diode based on a doped connection layer, to solve the problems of limited material selection required for the connection layer and poor connection layer properties in the conventional solution processed quantum dot light emitting diode, and to provide a simple and effective method for improving the performance of the solution processed quantum dot light emitting diode
In order to achieve the purpose, the solution processing serial quantum dot light emitting diode based on the doped connection layer comprises a bottom device and a top device, wherein the bottom device comprises a cathode, a first electron injection layer, a first quantum dot light emitting layer, a first hole transmission layer and a first hole injection layer which are sequentially stacked from bottom to top, the top device comprises a second electron injection layer, a second quantum dot light emitting layer, a second hole transmission layer, a second hole injection layer and an anode which are sequentially stacked from bottom to top, the first hole injection layer of the bottom device and the second electron injection layer of the top device are stacked, the second hole injection layer is made of PEDOT PSS solution, the first hole injection layer is made of PEDOT PSS-GO solution, and the second electron injection layer is made of ZnMgO-containing solution.
The principle and the advantages are as follows:
because the first hole injection layer is not made of a PEDOT/PSS solution in the prior art, but made of a PEDOT/PSS-GO solution, and the second electron injection layer is made of a ZnMgO-containing solution, the combination of the first hole injection layer and the second electron injection layer can be used as a solution processing doped connection layer of the series quantum dot light-emitting diode, namely the PEDOT/PSS/ZnMgO. The solution of PEDOT and PSS-GO prepared by the scheme effectively improves the property of the aqueous solution of PEDOT and PSS and increases the conductivity and the work function of the aqueous solution of PEDOT and PSS, so that compared with the solution of the prior art for processing the doped connecting layer PEDOT and PSS/ZnMgO, the solution of the PEDOT and PSS-GO/ZnMgO prepared by the scheme improves the wettability of the solution of the doped connecting layer PEDOT and PSS/ZnMgO on an organic transmission layer, thereby not only avoiding influencing the property of a lower layer film, but also helping the subsequent film to realize effective deposition. In addition, the reactions between PEDOT, PSS-GO and ZnMgO are reduced, the carrier injection and output level at the connecting layer is effectively increased, and the accumulation of carriers at the connecting layer is reduced, so that the non-radiative recombination is reduced, the radiative recombination efficiency is increased, and the electroluminescent performance of the device is improved. The problem of in the current solution processing quantum dot light emitting diode is solved: the selection of materials required by the connecting layer is limited, the properties of adjacent functional layers are influenced in the preparation process of the connecting layer, the carrier transport level at the interface of the connecting layer is limited, and the like, and a simple and effective method for improving the performance of the solution processed quantum dot light-emitting diode is provided.
Further, the first electron injection layer is made of a solution containing ZnO.
Has the advantages that: according to the scheme, the first electron injection layer is made of the solution containing ZnO, and compared with the first electron injection layer made of the ZnMgO solution in the prior art, the first electron injection layer can be better formed into a film on the ITO substrate, the electron mobility is better, the energy levels are more matched, and therefore more electron injection devices are provided.
Furthermore, the PEDOT/PSS solution is prepared by mixing a PEDOT/PSS aqueous solution and isopropanol according to the volume ratio of 1: 1.
Has the advantages that: compared with PEDOT PSS aqueous solution, the conductive material has higher conductivity.
And further, the PEDOT/PSS-GO solution is a mixed solution formed by doping inorganic oxide GO into the PEDOT/PSS solution.
Has the advantages that: the method has the advantages of effectively improving the properties of the PEDOT PSS aqueous solution, increasing the conductivity and the work function, reducing the hole injection and output potential barrier, increasing the wettability of the PEDOT PSS aqueous solution on the organic transmission layer, improving the deposition quality of the adjacent thin film layer and forming the solution processing doped connection layer PEDOT PSS-GO/ZnMgO with better effect.
Furthermore, the volume ratio of PEDOT to PSS to inorganic oxide GO in the PEDOT to PSS-GO solution is 5: 1.
Has the advantages that: compared with other PEDOT/PSS-GO solutions with the doping ratio of 5:1, the PEDOT/PSS-GO solution with the doping ratio of 5:1 has the best conductivity, work function and wettability.
The invention also aims to provide a method for manufacturing a solution-processed series quantum dot light-emitting diode based on a doped connection layer, which comprises the following steps:
s1, preparing material solutions of a hole injection layer and an electron injection layer, wherein the material solutions of the hole injection layer comprise a PEDOT (PSS) solution and a PEDOT (PSS-GO) solution; the material solution of the electron injection layer comprises a ZnMgO solution;
s2, preparing a cathode substrate, and cleaning, drying and carrying out ultraviolet ozone treatment on the cathode substrate;
s3, annealing treatment is carried out on the treated cathode substrate through a solution spin coating technology at different temperatures, a first electron injection layer, a first quantum dot light-emitting layer, a first hole transport layer, a first hole injection layer, a second electron injection layer, a second quantum dot light-emitting layer, a second hole transport layer and a second hole injection layer are sequentially prepared, and finally an anode is prepared through a vacuum thermal deposition technology;
the first hole injection layer is prepared from a PEDOT PSS-GO solution, the second electron injection layer is prepared from a ZnMgO solution, and the second hole injection layer is prepared from a PEDOT PSS solution.
The principle and the advantages are as follows:
compared with the prior art that the solution is used for processing the connection layer PEDOT of the serial quantum dot light-emitting diode, PSS/ZnMgO is doped through the organic oxide GO, the solution prepared by the method effectively improves the properties of the aqueous solution of the PEDOT and the PSS, increases the conductivity and the work function, improves the wettability of the solution on the organic transmission layer, and forms the effective solution processing doped connection layer PEDOT, PSS-GO/ZnMgO. The injection and output levels of carriers at the connecting layer are effectively increased, and the accumulation of the carriers at the connecting layer is reduced, so that the nonradiative recombination is reduced, the radiative recombination efficiency is increased, and the electroluminescent performance of the device is improved.
Furthermore, the PEDOT/PSS solution is prepared by mixing a PEDOT/PSS aqueous solution and isopropanol according to the volume ratio of 1: 1.
Has the beneficial effects that: compared with PEDOT PSS aqueous solution, the conductive material has higher conductivity.
Furthermore, the volume ratio of PEDOT to PSS to inorganic oxide GO in the PEDOT to PSS-GO solution is 5: 1.
Has the advantages that: compared with other PEDOT/PSS-GO solutions with the doping ratio of 5:1, the PEDOT/PSS-GO solution with the doping ratio of 5:1 has the best conductivity, work function and wettability.
Further, in step S3, the first hole injection layer and the second hole injection layer are prepared by a dynamic spin coating technique in an atmospheric environment, and the first electron injection layer, the quantum dot light emitting layer, the first hole transport layer, the second electron injection layer, the quantum dot light emitting layer, and the second hole transport layer are all prepared by a static spin coating technique in a glove box.
Has the advantages that: the best deposition effect of each functional layer can be achieved.
Further, in the step S3, the anode is an Al electrode, and the anode is in a vacuum degree of less than 10-4And (4) depositing and preparing in a high vacuum cavity of Pa.
Has the advantages that: the deposition formation of the anode is simpler and more practical, and the influence of water and oxygen in the air on the performance of the device can be avoided.
Drawings
FIG. 1 is a schematic plane view of a solution processed series quantum dot light emitting diode based on a doped connection layer according to an embodiment of the present invention;
FIG. 2 is a current-voltage characteristic curve of a PN junction formed by solution processing a connection layer under forward and reverse bias voltages;
FIG. 3 is an electroluminescence spectrum of a series quantum dot light emitting diode and a single quantum dot light emitting diode;
FIG. 4 is a graph of current efficiency versus voltage characteristics for a series quantum dot light emitting diode and a single quantum dot light emitting diode;
FIG. 5 shows the UV electron spectra of PEDOT PSS-DW film and PEDOT PSS-GO film;
FIG. 6 shows the contact angles of PEDOT PSS-DW film on the PVK organic layer and PEDOT PSS-GO film, respectively;
FIG. 7 is a current density-voltage characteristic curve of the photoelectric characteristics of a series quantum dot light emitting diode based on a doped connection layer PEDOT, PSS-GO/ZnMgO, and an undoped connection layer PEDOT, PSS-DW/ZnMgO;
FIG. 8 is a graph of luminance versus voltage characteristics of a series quantum dot light emitting diode;
fig. 9 is a current efficiency-voltage characteristic curve in the photoelectric characteristic of the tandem quantum dot light emitting diode;
fig. 10 is a power efficiency-voltage characteristic curve in the photoelectric characteristics of the tandem quantum dot light emitting diode.
Detailed Description
The following is further detailed by way of specific embodiments:
reference numerals in the drawings of the specification include: the cathode comprises a cathode 1, a first electron injection layer 2, a first quantum dot light-emitting layer 3, a first hole transport layer 4, a first hole injection layer 5, a second electron injection layer 6, a second quantum dot light-emitting layer 7, a second hole transport layer 8 and a second hole injection layer 9.
Examples
A solution processed series quantum dot light emitting diode based on a doped junction layer, substantially as shown in figure 1: including bottom devices and top devices. The bottom device comprises a cathode 1, a first electron injection layer 2, a first quantum dot light-emitting layer 3, a first hole transport layer 4 and a first hole injection layer 5 which are sequentially stacked from bottom to top. The top device comprises a second electron injection layer 6, a second quantum dot light emitting layer 7, a second hole transport layer 8, a second hole injection layer 9 and an anode which are sequentially stacked from bottom to top. The first hole injection layer 5 of the bottom device and the second electron injection layer 6 of the top device are arranged in a stacked mode, and the first hole injection layer 5 and the second electron injection layer 6 are used as solution processing doping connection layers of the series quantum dot light-emitting diode.
In this embodiment, the cathode 1 is made of ITO, the first electron injection layer 2 is made of a solution containing ZnO, the second hole injection layer 9 is made of a PEDOT: PSS solution, the first hole injection layer 5 is made of a PEDOT: PSS-GO solution, and the second electron injection layer 6 is made of a solution containing ZnMgO.
The embodiment of the invention also provides a method for manufacturing the solution processing series quantum dot light-emitting diode based on the doped connection layer, which comprises the following steps:
s1, preparing material solutions of a hole injection layer and an electron injection layer, wherein the material solutions of the hole injection layer comprise a PEDOT (PSS) solution and a PEDOT (PSS-GO) solution; the material solution of the electron injection layer comprises a ZnMgO solution and a ZnO solution dissolved in ethanol; the quantum dot light emitting layers are all made of CdSe-ZnS-containing solutions, and the hole transport layers are all made of PVK-containing solutions.
Organic polymers PEDOT, aqueous solutions of PSS (Heraeus-Clevios,4083), inorganic oxide Graphene Oxide (GO) and IPA were purchased and used without any modification.
S101, mixing a PEDOT/PSS aqueous solution with isopropanol IPA at normal temperature according to a volume ratio of 1:1, and stirring for 12 hours to obtain a PEDOT/PSS solution;
s102, proportioning the PEDOT/PSS solution and the inorganic oxide GO according to the volume ratio of 5:1, adding a magnet, and stirring at normal temperature for 12 hours to obtain the PEDOT/PSS-GO solution;
s2, preparing a cathode substrate, wherein the selection of the substrate is not limited strictly, and a hard substrate, such as a glass substrate, or a flexible substrate can be used. In this embodiment, the substrate is a glass substrate, and the cathode 1 is ITO. And then cleaning, drying and ultraviolet ozone treatment are carried out on the cathode substrate, and the method specifically comprises the following steps:
s201, sequentially cleaning the cathode substrate by using a detergent, deionized water, ethanol, acetone and isopropanol;
s202, putting the cleaned cathode substrate into a drying oven for drying;
s203, carrying out ultraviolet ozone treatment on the dried cathode substrate for 5 min.
S3, annealing the processed cathode substrate by a solution spin coating technology at different temperatures, sequentially preparing a first electron injection layer 2, a first quantum dot light-emitting layer 3, a first hole transport layer 4, a first hole injection layer 5, a second electron injection layer 6, a second quantum dot light-emitting layer 7, a second hole transport layer 8 and a second hole injection layer 9, and finally preparing an anode by a vacuum thermal deposition technology;
the method specifically comprises the following steps:
s301, transferring the processed cathode substrate into a glove box filled with nitrogen (the water oxygen content is less than 0.1ppm), putting the glove box on a spin coater, spin-coating a ZnO solution dissolved in ethanol at the speed of 2500r/min, and annealing at 120 ℃ for 20min to prepare a first electron injection layer 2;
s302, performing static spin coating on the first quantum dot light-emitting layer 3 by adopting a solution containing CdSe-ZnS at a speed of 2000r/min, and annealing at 110 ℃ for 30 min;
s303, spin coating and annealing the first hole transport layer 4 at the speed of 2000r/min by adopting a solution containing PVK;
s304, moving the processed device out of a glove box, spin-coating a mixed solution PEDOT (PSS-GO) solution by using a dynamic spin coating technology in an atmospheric environment, and annealing at 90 ℃ for 10min to prepare a first hole injection layer 5;
s305, moving the processed device into a glove box, putting the glove box on a spin coater, spin-coating a ZnMgO solution at the speed of 2500r/min, and annealing at 120 ℃ for 20min to prepare a second electron injection layer 6;
s306, performing static spin coating on the second quantum dot light-emitting layer 7 by adopting a solution containing CdSe-ZnS at a speed of 2000r/min, and annealing at 110 ℃ for 30 min;
s307, performing spin coating and annealing on the second hole transport layer 8 by adopting a solution containing PVK at the speed of 2000 r/min;
s308, moving the processed device out of the glove box, spin-coating the mixed solution PEDOT, namely the PSS solution by using a dynamic spin coating technology in an atmospheric environment, and annealing at 90 ℃ for 10min to prepare a second hole injection layer 9;
s309, transferring the processed device to a vacuum thermal evaporation system connected with a glove box, installing the device on a mask plate, and enabling the pressure in a high vacuum cavity to be lower than 1 x 10-4Growing an anode-Al electrode by thermal deposition under high vacuum condition of Pa (growth rate is about
S), the thickness of the anode is 100 nm.
And S4, packaging the prepared device in a glove box, and then moving out of the glove box for performance test.
The specific implementation process is as follows:
according to the scheme, the inorganic oxide GO is doped with PEDOT (PSS), so that the properties of the aqueous solution of the PEDOT and the PSS are effectively improved, the conductivity and the work function are increased, the wettability of the aqueous solution on an organic transmission layer is improved, and an effective solution processing doped connection layer PEDOT (PSS-GO/ZnMgO) is formed. The injection and output levels of carriers at the interface of the connecting layer are effectively increased, and the accumulation of the carriers at the interface is reduced, so that the non-radiative recombination is reduced, the radiative recombination efficiency is increased, and the electroluminescent performance of the device is improved.
The solution processing inverted serial quantum dot light-emitting diode is optimized by the scheme, the maximum brightness is 40877cd/m2, the maximum current efficiency is 19.6cd/A, and compared with a reference device without GO (the maximum brightness is 33868cd/m2, the maximum current efficiency is 13cd/A), the maximum brightness is increased by 21%, and the maximum current efficiency is improved by 51%. Under the premise of not changing the structure of the device and not increasing the functional layers, the problem of effective deposition of multilayer films in the solution processing TQLEDs is solved. And the method has low cost, simple operation and wide application range, provides a new idea for developing the high-efficiency QLED with low cost and large area in the future, and has great application prospect and research value.
In order to evaluate the effect of the solution processed doped connection layer PEDOT, PSS-GO/ZnMgO, on the series quantum dot light-emitting diode, four groups of ABCD devices are prepared through experiments, and the structures of the devices of each group are shown in the following table.
Table 1: device grouping and device structure table of each group
The group A device represents the device of the scheme and represents two serially connected quantum dot light-emitting diodes, in order to eliminate the influence of solution concentration change caused by doping on the performance of the device, the group B device is also prepared as a comparison group and represents the two serially connected quantum dot light-emitting diodes, and only a PEDOT/PSS-GO solution adopted for preparing the first hole injection layer 5 in the scheme is replaced by a PEDOT/PSS-DW solution according to a single variable principle, and the preparation method of the PEDOT/PSS-DW solution comprises the following steps: the PEDOT/PSS solution and the deionized water are proportioned according to the same volume ratio and stirred for 12 hours at normal temperature to form the PEDOT/PSS-DW solution. In order to show the advantages of the quantum dot light-emitting diode in series connection, quantum dot light-emitting diodes C and D with single structures are also prepared, wherein the group C device is a bottom device of the scheme and represents a single quantum dot light-emitting diode, the group D device is a top device of the scheme and also represents a single quantum dot light-emitting diode.
PSS-GO/ZnMgO, in order to study the carrier injection and output levels of the doped connection layer, PN junctions were prepared on the basis of this connection layer: and ITO/PEDOT, PSS-GO/ZnMgO/Al, and testing the current-voltage characteristics of the alloy under forward and reverse bias. As shown in FIG. 2, the PN junction shows better current-voltage characteristics under forward bias and reverse bias, which indicates that the PEDOT PSS-GO/ZnMgO heterojunction has better carrier injection and output levels at the same time. Therefore, the processing method based on the scheme obtains the solution processed series quantum dot light-emitting diode with excellent performance. As shown in fig. 3, the electroluminescence spectrum of the serial quantum dot light emitting diode a almost coincides with the electroluminescence spectra of the single quantum dot light emitting diodes C and D, which shows that the serial connection method does not affect the light emitting peak position of the device. As shown in fig. 4, the maximum current efficiency of the series quantum dot light emitting diode a is much greater than the maximum current efficiency of the single quantum dot light emitting diodes C and D, and is slightly greater than the sum of the maximum current efficiencies of the devices C and D.
The inverted TQLED processed by full solution can be effectively realized by taking a PEDOT (Primary insulated gate bipolar transistor) -PSS-GO/ZnMgO heterojunction as an intermediate connection layer. The introduction of GO improves the properties of the solution processed doped connection layer PEDOT, namely PSS-GO/ZnMgO comprehensively. As shown in FIG. 5, the work function of PEDOT, PSS-GO is 5.31eV, which is nearly 0.33eV higher than 4.98eV of PEDOT, PSS-DW, and the barrier of hole injection is reduced, thus being beneficial to hole injection devices. In addition, as shown in fig. 6, the contact angle of the liquid drops of PEDOT: PSS-GO on the organic layer PVK is 33 °, which is smaller than the contact angle of the liquid drops of PEDOT: PSS-GO on the PVK by 36 °, i.e. the wettability is better, and the atomic force microscope scanning result shows that the surface roughness of the film of PEDOT: PSS-GO formed on the PVK is 0.676nm, which is lower than 0.840nm of the film of PEDOT: PSS-GO, i.e. the film forming property of water-soluble PEDOT: PSS on the PVK is better due to the incorporation of GO.
And comparing the doped and undoped serial quantum dot light-emitting diodes A and the serial quantum dot light-emitting diodes B, and testing the photoelectric properties of the serial quantum dot light-emitting diodes. As shown in FIG. 7, by comparing and analyzing the current density-voltage change curves of the two, the current density of the serial quantum dot light-emitting diode based on PEDOT, PSS-GO is obviously smaller than that of the reference device, which shows that the electron and hole injection of the device is more balanced by the doping of GO, which is beneficial to improving the exciton recombination efficiency in the serial quantum dot light-emitting diode, and further improving the performances of the serial quantum dot light-emitting diode, such as the light-emitting brightness, the current efficiency and the like. As shown in fig. 8, under the same bias voltage, the light emitting brightness of the GO-doped serial quantum dot light emitting diode is higher, and the maximum value reaches 40877cd/m2, which is increased by 21% compared with the undoped serial quantum dot light emitting diode. As shown in fig. 9, it can be seen from the current efficiency-voltage characteristic curve that the maximum current efficiency of the GO-doped serial qd-led is 19.6cd/a, which is nearly 51% higher than that of the reference device 13 cd/a. As shown in fig. 10, the power efficiency-voltage characteristic curves of the doped and undoped serial quantum dot light emitting diodes are shown, and the power efficiency of the doped serial quantum dot light emitting diodes is 3.2lm/W, which is improved by 52% compared with the reference device (2.1 lm/W).
Based on the experimental results, the simple GO doping method can realize effective solution processing of the connection layer, further realize effective deposition of the solution processing of the series quantum dot light-emitting diode, and improve the electroluminescent performance of the solution processing of the series quantum dot light-emitting diode. And also provides an effective method for preparing the solution-processed multi-working-unit series structure device.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; these modifications and substitutions do not cause the essence of the corresponding technical solution to depart from the scope of the technical solution of the embodiments of the present invention, and are intended to be covered by the claims and the specification of the present invention.
Claims (5)
1. Solution processing series connection quantum dot light emitting diode based on doping connecting layer, its characterized in that: the LED chip comprises a bottom device and a top device, wherein the bottom device comprises a cathode, a first electron injection layer, a first quantum dot light emitting layer, a first hole transport layer and a first hole injection layer which are sequentially stacked from bottom to top, the top device comprises a second electron injection layer, a second quantum dot light emitting layer, a second hole transport layer, a second hole injection layer and an anode which are sequentially stacked from bottom to top, the first hole injection layer of the bottom device and the second electron injection layer of the top device are stacked, the second hole injection layer is made of PEDOT, namely PSS solution, the first hole injection layer is made of PEDOT-PSS-GO solution, and the second electron injection layer is made of ZnMgO-containing solution;
the PEDOT/PSS solution is prepared by mixing a PEDOT/PSS aqueous solution and isopropanol according to the volume ratio of 1: 1;
the PEDOT PSS-GO solution is a mixed solution formed by doping inorganic oxide GO into the PEDOT PSS solution;
the volume ratio of PEDOT to PSS to inorganic oxide GO in the PEDOT to PSS-GO solution is 5: 1.
2. The doped link layer based solution processed series quantum dot light emitting diode of claim 1, wherein: the first electron injection layer is made of a solution containing ZnO.
3. The method for manufacturing the serial quantum dot light-emitting diode based on solution processing of the doped connection layer is characterized by comprising the following steps of: the method comprises the following steps:
s1, preparing material solutions of a hole injection layer and an electron injection layer, wherein the material solutions of the hole injection layer comprise a PEDOT (PSS) solution and a PEDOT (PSS-GO) solution; the material solution of the electron injection layer comprises a ZnMgO solution and a ZnO solution;
s2, preparing a cathode substrate, and cleaning, drying and carrying out ultraviolet ozone treatment on the cathode substrate;
s3, annealing the processed cathode substrate by a solution spin coating technology at different temperatures, sequentially preparing a first electron injection layer, a quantum dot light-emitting layer, a first hole transport layer, a first hole injection layer, a second electron injection layer, a quantum dot light-emitting layer, a second hole transport layer and a second hole injection layer, and finally preparing an anode by a vacuum thermal deposition technology;
the first hole injection layer is prepared from a PEDOT PSS-GO solution, the second electron injection layer is prepared from a ZnMgO solution, and the second hole injection layer is prepared from a PEDOT PSS solution;
the PEDOT/PSS solution is prepared by mixing a PEDOT/PSS aqueous solution and isopropanol according to the volume ratio of 1: 1;
the volume ratio of PEDOT to PSS to inorganic oxide GO in the PEDOT to PSS-GO solution is 5: 1.
4. The method for manufacturing the quantum dot light-emitting diode based on the solution processing of the doped connection layer in series connection according to claim 3, wherein the method comprises the following steps: in the step S3, the first hole injection layer and the second hole injection layer are prepared by a dynamic spin coating technique in an atmospheric environment, and the first electron injection layer, the first quantum dot light emitting layer, the first hole transport layer, the second electron injection layer, the second quantum dot light emitting layer, and the second hole transport layer are all prepared in the glove box by a static spin coating technique.
5. The doped connection layer-based solution processing string of claim 3The manufacturing method of the quantum dot light-emitting diode is characterized in that: in the step S3, the anode is an Al electrode, and the anode is in a vacuum degree of less than 10-4And (4) depositing and preparing in a high vacuum cavity of Pa.
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