OLED light-emitting device and preparation method thereof

Abstract

The invention discloses an OLED light-emitting device and a preparation method thereof, and belongs to the technical field of organic electroluminescence, the OLED light-emitting device sequentially comprises a transparent substrate, an ITO anode, an anode modification layer, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode modification layer and a cathode from bottom to top, the anode modification layer adopts a PTAA thin film processed by PLASA equipment, and the cathode modification layer adopts a PTAA thin film processed by PLASA equipment. The main body material of the light emitting layer is DTBDQ or 2, 9-bis (naphthalene-2-yl)-4, 7-diphenyl-1, 10-phenanthroline; according to the invention, DTBDQ or NBPhen is introduced as a main body material and PTAA is adopted as an anode modification layer material, so that the organic electroluminescent device which can regulate and control the carrier density of a composite region, avoid direct injection luminescence of an electrode, reduce exciton non-radiative recombination and improve the luminous efficiency and the stability of the device is obtained; the maximum external quantum efficiency and the maximum current efficiency are improved, and the efficiency roll-off of the device is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescence, and particularly relates to an OLED light-emitting device and a preparation method thereof. Background Art

[0002] The performance of an organic light-emitting diode (OLED) with a sandwich p-i-n structure depends to a large extent on the efficiency of charge injection; in order to optimize the injection and transport of electrons and holes, a hole transport layer (HTL) is usually introduced between the indium tin oxide (ITO) electrode and the light-emitting layer to improve the light-emitting performance of the device. However, among currently commonly used organic semiconductor materials, the electron transport ability is generally weaker than the hole transport ability, resulting in the accumulation of carriers inside the device, the narrowing of the recombination region, and the aggravation of exciton quenching phenomenon, thereby affecting the efficiency and stability of the device.

[0003] The work function of the ITO electrode is about 4.7 eV, while the highest occupied molecular orbital (HOMO) energy level of most hole transport materials is close to -5.5 eV, which results in a large potential barrier during hole injection. In addition, the mismatch between the energy levels of organic materials and the work function of the electrode further aggravates the imbalance of charge injection and limits the migration efficiency of electrons. At the same time, metal electrode materials with low work function are easily affected by oxygen and moisture in the air, resulting in unstable interfaces, and thus reducing the lifetime and stability of OLEDs.

[0004] Poly[bis(4-phenyl)-(2,4,6-trimethylphenyl)amine] (PTAA), as a p-type polymer hole transport material, has been widely used in the field of solar cells due to its high carrier mobility, good conductivity, excellent optical transparency, and thermal stability. The HOMO energy level of PTAA is about -5.1 eV. Although its charge injection ability is strong, the HOMO energy level gap between it and the organic light-emitting layer is large, resulting in a large voltage loss during the operation of the device and limiting the improvement of the open-circuit voltage. In addition, the surface tension of the PTAA film is high, making it difficult to deposit a high-quality light-emitting layer film on it.

[0005] The interface characteristics between different materials have an important impact on charge separation and transport. By forming an internal electric field at the interface, charge separation can be effectively promoted. However, due to the complex interactions between materials, achieving ideal energy band alignment remains a technical challenge. Summary of the Invention

[0006] Aiming at the above problems existing in the prior art, the present invention provides an organic electroluminescent device and a preparation method thereof that can regulate the carrier density in the recombination region, avoid direct injection of light by the electrode, reduce non-radiative recombination of excitons, and improve the light-emitting efficiency and device stability.

[0007] The present invention is achieved through the following technical solutions:

[0008] An OLED light-emitting device, which includes a transparent substrate, an ITO anode, an anode modification layer, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode modification layer, and a cathode from bottom to top. The anode modification layer is a PTAA thin film treated by a PLASMA device. The host material of the light-emitting layer is DTBDQ or 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (NBPhen).

[0009] Further, the anode modification layer is obtained by spin-coating a PTAA solution at a high rotation speed of 5000 - 6000 r / min for 50 - 60 s in a nitrogen environment, then annealing at a temperature of 110 °C, and then moving it to a plasma processor for treatment at medium power for 5 - 10 min to obtain a PTAA thin film.

[0010] Further, the anode modification layer is a two-dimensional thin film formed by spin-coating a PTAA solution in a nitrogen atmosphere.

[0011] Further, the concentration of the PTAA solution used for spin-coating is 2 mg / mL.

[0012] Further, the material of the hole transport layer is 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC).

[0013] Further, the guest material of the light-emitting layer is the phosphorescent material bis(1-phenylisoquinolinato)acetylacetonate (Ir(piq)2acac), and the molar ratio of the guest material is 10%.

[0014] Further, the material of the electron transport layer is 1,3,5-tris(1-phenyl-1H-benzoimidazol-2-yl)benzene (TPBi) or 2,9-diphenyl-4,7-diphenyl-1,10-phenanthroline (NBPhen).

[0015] Further, the material of the cathode modification layer is lithium fluoride (LiF), and the cathode is aluminum (Al).

[0016] Further, the thickness of the hole transport layer is 40 nm, the thickness of the light-emitting layer is 20 nm, the thickness of the electron transport layer is 60 nm, the thickness of the cathode modification layer is 1 nm, and the thickness of the cathode is 100 nm.

[0017] On the other hand, the present invention also provides a method for preparing an OLED light-emitting device, and the specific steps are as follows:

[0018] Step 1: Take out the transparent substrate with pre-etched and deposited indium tin oxide (ITO) electrodes, remove the floating dust with a high-surface activity cleaner, and wash away the residual cleaner on the surface with deionized water;

[0019] Step 2: Take out the substrate, blow away the residual liquid on the surface with a nitrogen stream, and perform baking and plasma surface treatment in sequence;

[0020] Step 3: Dissolve an appropriate amount of PTAA powder in toluene and stir it with a magnetic stirrer for a certain time to prepare a clear solution;

[0021] Step 4: Take 100 μL of PTAA solution and spin-coat it on the substrate at a high speed of 5000 - 6000 r / min for 50 - 60 s in a nitrogen environment, then anneal it at a temperature of 110 °C for 8 - 12 min, and then move it to a plasma processor for treatment with medium power for 5 - 10 min to obtain a PTAA thin film on the substrate;

[0022] Step 5: Place the substrate with the PTAA thin film into a multi-source organic molecule deposition device, and control the sequential evaporation of a 40-nm hole transport layer, a 20-nm light-emitting layer, a 60-nm electron transport layer, a 1-nm cathode modification layer, and a 100-nm cathode under a pressure of 6×10 -4 Pa; the evaporation rate of the organic material is per second, the evaporation rate of LiF is per second, and the deposition rate of the Al electrode is approximately per second.

[0023] Further, in Step 2, the conditions for plasma surface treatment are: power of 300 W and time of 60 s.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] 1. For an OLED light-emitting device and its preparation method of the present invention, the host materials DTBDQ or NBPhen are used. Among them, when DTBD is selected as the bipolar host material, due to its high hole and electron mobilities, it can effectively expand the exciton recombination region in the light-emitting layer and achieve the dynamic balance of carriers; experiments show that for the device using DTBDQ, the maximum current efficiency is increased to 11.20 cd / A compared with the traditional host material (such as CBP), and the maximum external quantum efficiency of the device is also increased from 9.02% to 16.67%; when NBPhen is selected as the host material, due to the significant separation distribution of HOMO and LUMO in its molecule and the small overlap of wave functions, a small singlet-triplet energy level difference (ΔE ST) Experiments show that for the device using NBPhen, the maximum external quantum efficiency has increased from that of the traditional host material to 11.02%, and the maximum current efficiency has also increased from 4.272 cd / A to 6.292 cd / A.

[0026] 2. The present invention uses PTAA as the material for the anode modification layer. The PTAA thin film can increase the surface roughness of the anode. In addition, the film morphology of PTAA changes the flat morphology of the electrode and the surface electric field distribution. At this time, electrons can easily transfer from the LUMO of TAPC; introducing the PTAA thin film can reduce the width of the electroluminescence waveform diagram of the device from 87 nm to 84 nm, making the color display more concentrated; and by introducing the PTAA thin film modification, the probability of defects or impurities in the electrode and the organic layer becoming non-radiative recombination centers is reduced, so that the efficiency roll-off of the device at 1000 cd / m 2 in the working state decreases from 14.7% to 12.5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally denoted by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0028] Figure 1 : Schematic structural diagram of the organic electroluminescent device prepared by the present invention;

[0029] Figure 2 : Characteristic curve diagram of the organic electroluminescent device in Example 1 of the present invention;

[0030] Among them, (a) is the current density-voltage-luminance characteristic curve, (b) is the current efficiency-luminance-power efficiency characteristic curve, (c) is the external quantum efficiency-luminance characteristic curve, and (d) is the normalized electroluminescence spectrum;

[0031] Figure 3 : Characteristic curve diagram of the organic electroluminescent device in Example 2 of the present invention;

[0032] Among them, (a) is the current density-voltage-luminance characteristic curve, (b) is the current efficiency-luminance-power efficiency characteristic curve, (c) is the external quantum efficiency-luminance characteristic curve, and (d) is the normalized electroluminescence spectrum;

[0033] Figure 4 : Characteristic curve diagram of the organic electroluminescent device in Comparative Example 1 of the present invention;

[0034] Among them, (a) is the current efficiency-voltage characteristic curve, (b) is the power efficiency-voltage characteristic curve, and (c) is the external quantum efficiency-voltage characteristic curve;

[0035] Figure 5 : The external quantum efficiency-luminance characteristic curve of the organic electroluminescent device in Comparative Example 2 of the present invention;

[0036] Among them, (a) is the current efficiency-voltage characteristic curve, (b) is the power efficiency-voltage characteristic curve, and (c) is the external quantum efficiency-voltage characteristic curve; Detailed implementation manners

[0037] To clearly and completely describe the technical solutions of the present invention and their specific working processes, in combination with the accompanying drawings of the specification, the detailed implementation manners of the present invention are as follows:

[0038] The present invention uses DTBDQ and NBPhen as the host materials of the light-emitting layer. The thermal stability of the host materials of the light-emitting layer has a great influence on the operation of the OLED device under high-brightness conditions. Good thermal stability is beneficial to increasing the device stability and lifespan. In the TGA test, under the protection of a nitrogen atmosphere, the experimental host materials were heated at a rate of 10 °C / min. The thermal decomposition temperature (T d ) of DTBDQ at 5% weight loss is 466 °C. Comparison with other host materials shows that DTBDQ has good thermal stability, as shown in Table 1;

[0039] Table 1 Comparison of thermal stability of host materials

[0040] Host material of the light-emitting layer <![CDATA[T d (5%℃)]]> DTBDQ 466 NBPhen 340 CBP 320

[0041] The present invention uses PTAA as the anode modification layer. PEDOT:PSS, as a highly conductive organic material with self-assembly ability, is often used as a hole transport layer alone in solution-processable OLED devices. However, the conductivity of PTAA, also a polymer organic material, is better than that of PEDOT:PSS under experimental conditions, verifying the potential of PTAA in carrier transport, as shown in Table 2 specifically;

[0042] Table 2: Comparison of the conductivity of PEDOT:PSS and PTAA thin films prepared under the same laboratory conditions

[0043] Material name Conductivity (S / cm) PEDOT:PSS 414.564 PTAA 538.5472

[0044] Example 1

[0045] Such as Figure 1As shown in the figure, this embodiment provides an OLED light-emitting device, which includes a transparent substrate, an ITO anode, an anode modification layer, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode modification layer, and a cathode from bottom to top. The anode modification layer is a PTAA thin film treated by PLASMA, and the host material selected in this embodiment is NBPhen.

[0046] In this embodiment, a red phosphorescent organic light-emitting device with a device structure of ITO / PTAA / TAPC(40nm) / NBPhen:Ir(piq)2acac = 10:1(20nm) / TPBi(50nm) / LiF(1nm) / Al(100nm) is prepared using NBPhen as the host material. Among them, the doping molar ratio of the light-emitting layer Ir(piq)2acac is 10%.

[0047] This embodiment also provides a method for manufacturing an OLED light-emitting device, which specifically includes the following steps:

[0048] Clean the substrate composed of the ITO anode and the glass substrate, dry the substrate with a nitrogen stream and bake it at 100 °C for 10 min. Then, perform plasma surface treatment with the maximum power of the O2-Plasma equipment for 10 min. After that, take 100 μL of the PTAA solution and spin-coat it at a speed of 5000 - 6000 r / min for 50 - 60 s in a nitrogen environment. Subsequently, perform annealing treatment at a temperature of 110 °C for 8 - 12 min. Then, move the thin film to the plasma processor and process it for 5 min in the "mid" gear. After the treatment, take it out and place it in a multi-source organic vacuum evaporation equipment. In a 6*10 -4 Pa air pressure environment, sequentially evaporate the hole transport layer TAPC on the ITO, with a thickness of 40 nm and an evaporation rate The light-emitting layer is NBPhen: and Ir(piq)2acac. The mass ratio of the host material to the red phosphorescent guest material in the light-emitting layer is 10:1, with a thickness of 20 nm and an evaporation rate The electron transport layer TPBi has a thickness of 50 nm and an evaporation rate The cathode modification layer LiF, evaporation rate With a thickness of 1 nm. Then, transfer the substrate to the metal evaporation area, keep the above vacuum conditions unchanged, and continue to evaporate Al as the metal cathode above LiF, with an evaporation rate With a thickness of greater than or equal to 100 nm.

[0049] As Figure 2 shown in (a)-(d) in the figure, the device prepared in this embodiment can achieve a luminous intensity of 6067 cd / m at a driving voltage of 9.5 V 2, the current efficiency and power efficiency can reach 8.62 cd / A and 4.66 lm / W, and the external quantum efficiency can reach 12.89%, 1000 cd / m 2 Under the working conditions, the current efficiency, power efficiency, and external quantum efficiency can still be maintained at 11.02%, and the efficiency roll-off is 14.5%.

[0050] Example 2

[0051] In this example, an OLED light-emitting device is prepared using DTBDQ as the host material;

[0052] Specifically, in this example, a red phosphorescent OLED device with a structure of ITO / PTAA / TAPC(40 nm) / DTBDQ:Ir(piq)2acac = 10:1(20 nm) / TPBi(50 nm) / LiF(1 nm) / Al(100 nm) is prepared using DTBDQ as the host;

[0053] As Figure 3 shown in (a)-(d) of 2 , the luminous intensity of the device prepared in this example can reach 7691 cd / m 2 under a driving voltage of 9.5 V, the current efficiency and power efficiency can reach 11.20 cd / A and 4.40 m / W, and the external quantum efficiency can reach 16.67%, 1000 cd / m

[0054] Comparative Example 1

[0055] As a control group with Example 1, the process parameters were adjusted during the production of the PTAA film to observe the performance changes. This comparative example includes 3 components, namely:

[0056] Device ① is different from Example 1 in that the PTAA processing method is evaporation coating on the ITO glass substrate at a pressure of 6*10 -4 Pa and a temperature of 220 - 300 °C, and the structure is:

[0057] ITO / PTAA / TAPC(40 nm) / NBPhen:Ir(piq)2acac = 10:1 20 nm / TPBi

[0058] (50 nm) / LiF 1 nm / Al(100 nm).

[0059] Device ② is different from Example 1 in that the rotation speed of the spin coater during the PTAA processing is 800 - 1000 r / s and spin coating is performed at a low speed for 10 s, and the structure is:

[0060] ITO / PTAA / TAPC (40 nm) / NBPhen:Ir(piq)2acac = 10:1 20 nm / TPBi

[0061] (50 nm) / LiF (1 nm) / Al (100 nm);

[0062] The difference between Device ③ and Example 1 is that after PTAA is spin-coated, it is not processed by a PLASMA device. The structure is:

[0063] ITO / PTAA / TAPC (40 nm) / NBPhen:Ir(piq)2acac = 10:1 20 nm / TPBi

[0064] 50 nm / LiF 1 nm / Al 100 nm;

[0065] The performance parameters of the organic light-emitting devices in Comparative Example 1 are shown in Table 1.

[0066] Table 1 Comparison of the luminescence performance of Devices ①-③ and the devices prepared in Example 1

[0067]

[0068]

[0069] From the comparison of the experimental device results, it can be seen that the processing conditions of PTAA do not significantly affect the color display and purity of OLED devices. The peaks are all in the 624-630 nm red light band, showing high consistency. When using the vacuum evaporation processing method, Device ① effectively avoids the introduction of organic solvents during the processing. Not only is the emission peak closer to the pure red region specified by CIE, but also has a higher current efficiency. However, the high processing temperature damages the purity and stability of PTAA, showing a lower device efficiency; the low solubility of PTAA in solvents results in unsatisfactory film formation uniformity at low rotation speeds. Therefore, while the performance of Device ② decreases, the overall thickness of PTAA increases, and the electron transport barrier between ITO and the light-emitting layer is higher, accompanied by an increase in the turn-on voltage; the performance degradation of Device ③ indicates that the introduction of the PLASMA treatment process effectively increases the surface roughness of PTAA, reduces the surface tension, and enables the light-emitting layer material to adhere to it uniformly and effectively.

[0070] Comparative Example 2

[0071] As the control group of Example 2, other organic semiconductor light-emitting materials are used as the host and guest of the light-emitting layer. This comparative example includes 5 devices:

[0072] The structure of Device ① is:

[0073] ITO / PTAA / TAPC(40 nm) / CBP:Ir(piq)2acac = 10:1(20 nm) / TPBi

[0074] (50 nm) / LiF 1 nm / Al(100 nm);

[0075] Device Structure ②: ITO / PTAA / TAPC(40 nm) / mCP:Ir(dmdppr-dmp)2(dvim) = 10:1(20 nm) / TPBi(50 nm) / LiF 1 nm / Al(100 nm);

[0076] Device Structure ③: ITO / PTAA / TAPC(40 nm) / PO-T2T:Ir(dmdppr-dmp)2(dvim) = 10:1(20 nm) / TPBi(50 nm) / LiF

[0077] 1 nm / Al(100 nm);

[0078] Device Structure ④: ITO / PTAA / TAPC(40 nm) / 26DCzPPy:Ir(piq)2acac = 10:1(20 nm) / TPBi(50 nm) / LiF 1 nm / Al(100 nm);

[0079] Device Structure ⑤: ITO / PTAA / TAPC(40 nm) / BCP:Ir(piq)2acac = 10:1(20 nm) / TPBi(50 nm) / LiF 1 nm / Al(100 nm);

[0080] The comparison performance table of different host and guest materials in the light-emitting layer is shown in Table 4;

[0081] Table 4 Comparative Example 2: Comparison of the light-emitting performance of Devices ① - ⑤:

[0082]

[0083] It can be seen from the test results of the above devices in Table 5 that: as a key factor in device performance, the host material of the light-emitting layer disperses and provides a rigid environment for the guest light-emitting material (Emitter / Dopant), while regulating the carrier transport and energy transfer processes. Since most traditional host materials such as CBP are hole-type host materials, showing stronger hole transport ability, there is a huge difference between the hole transport and electron transport properties of materials such as CBP. Taking CBP as an example, the LUMO energy level of CBP is 2.9 eV, the LUMO energy level of TPBi is 2.8 eV, and the electron injection barrier is 0.1 eV. Compared with the device using DTBDQ as the host material of the light-emitting layer, the injection speed of carriers is significantly slowed down, resulting in a decrease in the overall current density of the device.

[0084] Table 5 Photophysical Properties of Host Materials

[0085] Name <![CDATA[Energy level of T1 (eV)]]> HOMO (eV) LUMO (eV) CBP 2.6 6.0 2.9 mCP 3.0 5.9 2.4 PO-T2T 2.9 7.5 3.0 BCP 2.6 6.4 2.9 26DCzPPy 3.0 6.1 2.6

[0086] The triplet energy levels of carbazole-pyridine materials are usually in the range of 2.7–3.0 eV. The high triplet energy levels make them match the T1 energy levels of phosphorescent materials such as Ir complexes. In OLED devices, it is usually required that the T1 energy level of the host material is 0.2–0.3 eV higher than that of the guest. In this example, using host materials such as mCP results in energy level mismatch, leading to carrier recombination at non-ideal positions, reducing device efficiency or causing non-radiative recombination.

[0087] The electron-donating group dibenzothiophene in the bipolar host material DTBDQ used in the present invention is a hole-transporting group with strong hole-transporting ability. The electron-accepting dibenzo[f,h]quinoxaline group has two nitrogen atoms with strong electronegativity. The two groups are connected by a meta-phenylene, maintaining a relatively high triplet energy level. The overall molecule exhibits bipolar transport characteristics. The current efficiency of the OLED device prepared with DTBDQ as the host can reach 11.20 cd / A, and the power efficiency can reach 4.40 lm / W. It can improve the device luminescence efficiency to 16.67% and reduce efficiency roll-off.

[0088] The molecular structure of the host material DTBDQ is as follows:

[0089]

[0090] The molecular structure of the phosphorescent material Ir(piq)2acac is as follows:

[0091]

[0092] (Iridium bis[2-[5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyridyl-kN1]-4,6-dimethylphenyl-kC]-(2,8-dimethyl-4,6-nonanedionato-kO4,kO6)) The molecular structure of Ir(dmdppr-dmp)2(dvim) is as follows:

[0093]

[0094] The molecular structures of the host materials CBP and BCP are as follows:

[0095]

[0096] The molecular structure of NBPhen is as follows:

[0097]

[0098] The molecular structures of the hole and electron transport materials TAPC and TPBi are as follows:

[0099]

[0100] The molecular structures of the traditional host materials mCP and PO-T2T are as follows:

[0101]

[0102] In the examples of the present invention, the thickness and growth rate of the thin film grown by the vacuum thermal evaporation process were measured by an L-400 film thickness controller produced in the United States. The performance of the fabricated devices was tested under normal temperature conditions in air using an optoelectronic test system based on a Keithley 2400 current-voltage source and an Otsuka Electronics MPCD-9800 spectrometer.

[0103] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0104] In addition, it should be noted that, in the case of no conflict, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0105] Furthermore, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. An OLED light-emitting device, characterized in that, From bottom to top are a transparent substrate, an ITO anode, an anode modification layer, a hole transport layer, a light-emitting layer, an electron transport layer, a cathode modification layer, and a cathode. The anode modification layer uses a PTAA thin film treated by a PLASMA device. The host material of the light-emitting layer is DTBDQ or 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline.

2. An OLED light-emitting device according to claim 1, characterized in that, The anode modification layer is obtained by spin-coating a PTAA solution at a high rotation speed of 5000 - 6000 r / min for 50 - 60 s in a nitrogen environment, then annealing at a temperature of 110 °C, and then moving it to a plasma processor for treatment with medium power for 5 - 10 min to obtain a PTAA thin film.

3. An OLED light-emitting device according to claim 1, characterized in that, The anode modification layer is a two-dimensional thin film formed by spin-coating a PTAA solution in a nitrogen atmosphere.

4. An OLED light-emitting device according to claim 3, characterized in that, The concentration of the PTAA solution used for spin-coating is 2 mg / mL.

5. An OLED light-emitting device according to claim 1, wherein The material of the hole transport layer is 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline].

6. An OLED light-emitting device according to claim 1, characterized in that, The guest material of the light-emitting layer is the phosphorescent material bis(1-phenylisoquinolinato)acetylacetonate, and the molar ratio of the guest material is 10%.

7. An OLED light-emitting device according to claim 1, characterized in that, The material of the electron transport layer is 1,3,5-tris(1-phenyl-1H-benzoimidazol-2-yl)benzene or 2,9-diphenyl-4,7-diphenyl-1,10-phenanthroline.

8. An OLED light-emitting device according to claim 1, characterized in that, The material of the cathode modification layer is lithium fluoride, and the cathode is aluminum.

9. An OLED light-emitting device according to claim 1, characterized in that, The thickness of the hole transport layer is 40 nm, the thickness of the light-emitting layer is 20 nm, the thickness of the electron transport layer is 60 nm, the thickness of the cathode modification layer is 1 nm, and the thickness of the cathode is 100 nm.

10. The manufacturing method of an OLED light-emitting device according to claim 1, characterized in that, The specific steps are as follows: Step 1: First, take out the transparent substrate with a pre-etched and deposited indium tin oxide electrode and remove the floating dust with a high-surface-activity cleaner, and use deionized water to wash away the residual cleaner on the surface. Step 2: Take out the substrate and blow away the residual liquid on the surface with a nitrogen stream, and perform baking and plasma surface treatment in sequence; among them, the conditions for plasma surface treatment are: power is 300 W, and time is 60 s. Step 3: Take an appropriate amount of PTAA powder and dissolve it in toluene, and configure it into a clear solution after stirring for a certain time with a magnetic stirrer. Step 4: Take 100 μL of the PTAA solution and spin-coat it on the substrate at a high rotation speed of 5000 - 6000 r / min for 50 - 60 s in a nitrogen environment, then anneal at a temperature of 110 °C for 8 - 12 min, and then move it to a plasma processor for treatment with medium power for 5 - 10 min to obtain a PTAA thin film on the substrate. Step Five: Place the substrate with the PTAA film into a multi-source organic molecule deposition equipment, and control the sequential evaporation of a 40-nm hole transport layer, a 20-nm light-emitting layer, a 60-nm electron transport layer, a 1-nm cathode modification layer, and a 100-nm cathode under a pressure of 6×10 -4 Pa; the evaporation rate of the organic material is per second, the evaporation rate of LiF is per second, and the deposition rate of the Al electrode is approximately per second.

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