CN109004096A - A kind of structure is simple and efficient blue-fluorescence Organic Light Emitting Diode - Google Patents

Abstract

The simple and efficient blue-fluorescence Organic Light Emitting Diode the present invention relates to a kind of structure, belong to basic electrical component technical field, which includes the substrate being cascading, anode layer, anode interface layer, hole transport and luminescent layer, electron transfer layer, cathode interface layer and cathode layer.Wherein, hole transport and luminescent layer doped with 2- methyl -9,10- bis- (2- naphthalene) anthracene of 1-4- bis--[4- (N, N- diphenyl) amino] styryl benzene by being made.Blue-fluorescence Organic Light Emitting Diode not only has simple structure, and efficiency also with higher overcomes multilayered structure in the prior art and is conducive to the technology prejudice that final efficiency improves, can be widely used in the fields such as high efficiency organic light emitting display and illumination.

Description

A Simple and High Efficiency Blue Fluorescent Organic Light-Emitting Diode

technical field

The invention belongs to the technical field of basic electrical components, and in particular relates to a blue fluorescent organic light-emitting diode with simple structure and high efficiency.

Background technique

In 1963, Pope et al. in the United States discovered the phenomenon of electroluminescence for the first time by passing direct current on single crystal anthracene, and this single-layer structure device (as shown in Figure 1) was too thick (20 microns) due to the organic layer anthracene, resulting in The driving voltage is as high as 400V, and the luminous efficiency and brightness are extremely low, so it has not received much attention. In 1987, Tang et al. proposed a double-layer structure device with hole transport (as shown in Figure 2). Compared with the single-layer structure, the double-layer structure greatly improves the hole injection due to the introduction of the hole transport layer, so this device structure can effectively solve the problems of carrier injection, transport and recombination, thereby reducing the driving voltage. And the brightness of the device is improved. In 1988, Adachi and others in Japan proposed a three-layer device structure. They extended the three-layer structure on the basis of the double-layer structure (as shown in Figure 3). It is characterized in that the hole transport layer, the light-emitting layer, and the electron transport layer use Different materials can make the energy level of the device structure well matched; and the carrier recombination and exciton diffusion are limited in the light-emitting layer, and the recombination area is far away from the electrode, thereby reducing the quenching of excitons and balancing The injection efficiency of carriers can improve the luminous efficiency and brightness of the device, but the disadvantage is that it increases the complexity of the preparation process. In recent years, in order to optimize the energy level matching between the functional layers of the organic light-emitting diode (OLED) device and balance the carrier transport capability of the device so as to improve the luminous efficiency of the organic electroluminescent device, people will introduce A variety of functional layers with different roles (as shown in Figure 4), such as the introduction of a hole blocking layer and an electron blocking layer. For the introduction of the hole blocking layer and the electron blocking layer, the deeper highest occupied orbital (HOMO) energy level of the hole blocking layer and the lower lowest unoccupied orbital (LUMO) energy level of the electron blocking layer are used to block holes respectively. And the migration of electrons, reduce the leakage current, limit the carrier area, and improve the luminous efficiency of the device.

Due to the energy level mismatch between the anode layer and the cathode layer and the organic layer (such as hole transport layer, electron transport layer). At the same time, there are micro-defects such as pinholes and grain boundaries in the anode layer and the cathode layer, and the anode layer and the cathode layer need to be respectively introduced into the anode interface layer (hole injection layer) and the cathode interface layer (electron injection layer) for modification. On the one hand, it can effectively reduce the injection barrier of holes and electrons, making it easier for holes and electrons to be injected from the anode and cathode into the organic layer, thereby reducing the starting voltage and working voltage of the device and improving the power efficiency of the device. In addition, the anode interface layer and the cathode interface layer are also conducive to improving the interface characteristics between the electrode and the organic layer, and also play a very effective role in reducing leakage current and improving device stability. Therefore, in the existing OLED structure, the anode interface layer Both the cathode interface layer and the cathode interface layer are essential functional modification layers.

In order to improve the luminous efficiency and brightness of OLED devices and reduce the start-up voltage and working voltage of OLED devices, conventional research ideas are achieved by adding corresponding functional layers. For example, the introduction of a hole transport layer improves the luminous efficiency and Brightness, and reduce the driving voltage; the three-layer structure (hole transport layer, light-emitting layer and electron transport layer) improves the luminous efficiency and brightness compared with the two-layer structure. At present, OLED devices in practical use basically use three-layer or more structures. Although single-layer and two-layer structures are simple in structure, they are basically not used due to poor performance such as luminous efficiency and brightness.

Blue light, one of the three primary colors, is essential to realize OLED-based full-color displays and solid-state lighting. Compared with high-efficiency and long-life red and green OLEDs, blue fluorescent OLEDs still suffer from poor performance in terms of efficiency and stability. Among them, the bottleneck restricting the performance of blue fluorescent OLED devices is the wide bandgap (about 3.0eV) of blue light-emitting materials, and it is difficult for wide-bandgap organic materials to meet the dual requirements of high fluorescence efficiency and structural stability at the same time. On the one hand, the wide bandgap restricts the luminescent material from having a large conjugated structure, that is, the molecular size cannot be too large, and the small molecular structure will reduce the thermal stability of the material; on the other hand, efficient fluorescent blue light strongly depends on large molecules Rigid structure, and too much rigidity of the molecular structure leads to poor stability of the film material. In addition, the wide band gap makes the balanced injection and transport of electrons and holes difficult, thus restricting the improvement of luminous efficiency. In addition, the exciton formation and light-emitting region of blue light is relatively wide, which easily causes the interface exciplex to emit light, and the spectrum is red-shifted, resulting in unsatisfactory spectral characteristics. Since the hole mobility of the hole transport material is generally superior to the electron mobility of the electron transport material, a large number of holes will accumulate in the light-emitting layer and impair the carrier balance, and it is usually necessary to improve the structure of the light-emitting layer. For example, increasing the number of layers of the light-emitting layer or introducing a hole blocking layer to achieve the function of adjusting the carrier balance, this method increases the process cost and complicates the device structure.

In summary, the current technical solutions in this field are mainly to improve the performance indicators such as luminous efficiency, power efficiency and brightness of blue fluorescent OLED devices by adding different functional layers. Therefore, today's high-efficiency blue fluorescent OLED devices are basically It adopts a multi-layer structure, that is, several functional layers are added between the electrode and the light-emitting layer of the blue fluorescent OLED, such as a multi-layer light-emitting layer, a hole blocking layer, etc. Although the multi-layer structure is conducive to the realization of the final high efficiency, the use of Such a structure also brings a series of problems such as high cost, low reliability, complex process, and low production efficiency, which seriously restricts the low cost and large-scale application of blue fluorescent OLED production. Therefore, there is an urgent need for a blue fluorescent OLED device structure with simple structure and high efficiency.

Contents of the invention

In view of this, one of the objectives of the present invention is to provide a blue fluorescent organic light emitting diode with simple structure and high efficiency.

To achieve the above object, the present invention provides the following technical solutions:

1. A blue fluorescent organic light-emitting diode with simple structure and high efficiency, the diode includes a hole transport and light emitting layer and an electron transport layer, and the hole transport and light emitting layer is doped with 1-4-di- [4-(N,N-diphenyl)amino]styrylbenzene from 2-methyl-9,10-bis(2-naphthyl)anthracene.

Preferably, the diode also includes a substrate, an anode layer, an anode interface layer, a cathode interface layer, and a cathode layer; The cathode layer and the cathode layer are stacked in sequence.

Preferably, the substrate is made of glass, quartz or polyethylene terephthalate.

Preferably, the anode layer is made of indium tin oxide, Al ₂ O ₃ doped ZnO or fluorine doped SnO ₂ ; the cathode layer is made of Al, Sm or Ca.

Preferably, the anode interface layer is made of poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, MoO ₃ , WO ₃ or V ₂ O ₅ .

Preferably, the electron transport layer is composed of 4,7-diphenyl-1,10-phenanthroline, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 2,9-Dimethyl-4,7-biphenyl-1,10-phenanthroline, 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)- 1,3,4-oxadiazole] or 3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole to make.

Preferably, the cathode interface layer is made of LiF, Cs ₂ CO ₃ or 8-hydroxyquinoline-lithium.

Preferably, the doping of 1-4-bis-[4-(N,N-diphenyl)amino]styrylbenzene in the 2-methyl-9,10-bis(2-naphthyl)anthracene The amount is 1-5 wt%.

Preferably, the thickness of the hole transport and light emitting layer is 60-90 nm.

Preferably, when the anode interface layer is poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid, the thickness is 20-40nm, and when the anode interface layer is MoO3, the thickness is _0.5-15nm , and the anode interface layer is The thickness of WO ₃ is 0.5-5nm, the thickness of the anode interface layer is 0.5-5nm when V ₂ O ₅ ; the thickness of the electron transport layer is 20-50nm; the thickness of the cathode interface layer is 0.5-1nm when the cathode interface layer is LiF Cs ₂ CO ₃ has a thickness of 1-20nm, and a cathode interface layer of 8-hydroxyquinoline-lithium has a thickness of 1-5nm.

The working principle and beneficial effects of the present invention are: the present invention provides a blue fluorescent organic light-emitting diode with simple structure and high efficiency. In the diode, the hole transport layer and the light-emitting layer are integrated to construct a The light-emitting layer, on the one hand, reduces the interface between the hole transport layer and the light-emitting layer in the traditional structure, and simplifies the structure of the device; on the other hand, the thickness of the hole transport and light-emitting layer is larger than that of the simple light-emitting layer in the traditional structure. , thus expanding the recombination region of the excitons, which is beneficial to the energy transfer between the host and the guest, improving the recombination rate and utilization rate of the excitons, thereby improving the luminous efficiency of the diode; The material of the hole transport and light-emitting layer and the doping amount in the material. The hole transport and light-emitting layer prepared with this material not only serves as a carrier for energy transfer between the host and the guest, but also effectively performs exciton recombination to achieve high-efficiency light emission. function, and can also play a role in regulating the hole transport ability, because the dopant in the material can act as a trap that affects the charge transport mechanism and has a scattering effect, so that the excess holes injected from the anode layer are captured by the trap or pass through The effect of scattering is delayed, which can regulate the number of holes entering the light-emitting layer, thereby improving the balance of carriers, and finally improving the efficiency of the diode. The blue fluorescent organic light-emitting diode in the present invention not only has a simple structure, but also has high efficiency, which overcomes the technical prejudice that the multi-layer structure is beneficial to the improvement of the final efficiency of the diode generally believed by those skilled in the art. The double-layer structure that people abandon due to technical prejudice not only makes the luminous efficiency of the blue fluorescent organic light-emitting diode finally prepared far higher than that of the blue fluorescent organic light-emitting diode with multi-layer structure in the prior art, but also overcomes the existing problems. A series of problems such as high cost, low reliability, complex process, and low production efficiency brought about by the multilayer structure in the technology have effectively promoted the low cost and large-scale application of blue fluorescent organic light-emitting diodes, and have great potential Economic Value.

Description of drawings

In order to make the purpose, technical scheme and beneficial effect of the present invention clearer, the present invention provides the following drawings for illustration:

1 is a schematic diagram of an organic light-emitting diode with a single-layer structure;

2 is a schematic diagram of an organic light emitting diode with a double-layer structure;

3 is a schematic diagram of an organic light emitting diode with a three-layer structure;

4 is a schematic diagram of an organic light emitting diode with a multilayer structure;

5 is a schematic diagram of a blue fluorescent organic light-emitting diode in the present invention;

Fig. 6 is a performance test diagram of the blue fluorescent organic light-emitting diode in the implementation 1;

FIG. 7 is a performance test diagram of blue fluorescent organic light-emitting diodes in implementation 2;

Fig. 8 is a performance test diagram of blue fluorescent organic light-emitting diode in implementation 3;

Fig. 9 is a performance test diagram of blue fluorescent organic light-emitting diodes in implementation 4;

Fig. 10 is a performance test diagram of blue fluorescent organic light-emitting diode in implementation 5;

Fig. 11 is a performance test diagram of the blue fluorescent organic light-emitting diode in implementation 6;

Fig. 12 is a performance test chart of the blue fluorescent organic light-emitting diode in comparative implementation 1;

Fig. 13 is a performance test diagram of blue fluorescent organic light-emitting diodes in comparative implementation 2;

14 is a graph showing the current-voltage (I-V) characteristics and impedance spectrum analysis results of three single-hole devices in Example 7.

Among them, in Figure 6 to Figure 13, a is the maximum luminous efficiency test chart of the blue fluorescent organic light emitting diode, b is the maximum power efficiency test chart of the blue fluorescent organic light emitting diode, c is the blue fluorescent organic light emitting diode The maximum external quantum efficiency test chart, d is the electroluminescence spectrum test chart. In Fig. 14, a is the IV diagram of three kinds of single hole devices, b is the impedance-voltage (ZV) diagram of three kinds of single hole devices, and c is the phase angle-voltage of three kinds of single hole devices Figure, d is the capacitance-voltage (CV) diagram of three single-hole devices.

Detailed ways

Preferred embodiments of the present invention will be described in detail below.

Fig. 5 is a schematic diagram of a blue fluorescent organic light-emitting diode with simple structure and high efficiency in the present invention. As can be seen from Fig. 5, the diode is sequentially stacked with substrate, anode layer, anode interface layer, hole Transport and light-emitting layer, electron transport layer, cathode interface layer and cathode layer.

In each embodiment,

ITO is indium tin oxide;

PEDOT:PSS is poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid;

NPB is N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine;

DSA-Ph is 1-4-bis-[4-(N,N-diphenyl)amino]styrylbenzene, the structure of which is shown in formula I;

MADN is 2-methyl-9,10-di(2-naphthyl)anthracene, its structure is shown in formula II;

BPhen is 4,7-diphenyl-1,10-phenanthroline;

LiF is lithium fluoride;

Al is aluminum.

Example 1

A blue fluorescent organic light-emitting diode with simple structure and high efficiency, which includes a 1mm thick glass substrate, an ITO anode layer with a square resistance of 15Ω/□, a 30nm thick PEDOT:PSS anode interface layer, A 60nm-thick MADN:DSA-Ph hole-transport and light-emitting layer with a doping amount of 3wt%, a 30nm-thick BPhen electron-transport layer, a 0.7nm-thick LiF cathode interface layer and a 100nm-thick Al cathode layer. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency, and electroluminescent spectrum and color coordinates of the diode were tested respectively, and the results are shown in Figure 6, wherein a in Figure 6 is the maximum luminous efficiency test chart, and b in Figure 6 is the maximum Power efficiency test chart, c in Figure 6 is the maximum external quantum efficiency test chart, d in Figure 6 is the electroluminescent spectrum test chart, and the color coordinates are listed in Table 1.

Example 2

The difference from Example 1 is that the thickness of the MADN:DSA-Ph hole-transporting and light-emitting layer with a doping amount of 3wt% is 70nm. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency and CIE color coordinates of the diode were tested respectively, and the results are shown in Figure 7, wherein a in Figure 7 is the maximum luminous efficiency test chart, and b in Figure 7 is the maximum power efficiency test chart , c in Figure 7 is the maximum external quantum efficiency test chart, d in Figure 7 is the electroluminescent spectrum test chart, and the color coordinates are listed in Table 1.

Example 3

The difference from Example 1 is that the thickness of the MADN:DSA-Ph hole-transporting and light-emitting layer with a doping amount of 3wt% is 80nm. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency and CIE color coordinates of the diode were tested respectively, and the results are shown in Figure 8, wherein a in Figure 8 is the maximum luminous efficiency test chart, and b in Figure 8 is the maximum power efficiency test chart , c in Figure 8 is the maximum external quantum efficiency test chart, d in Figure 8 is the electroluminescent spectrum test chart, and the color coordinates are listed in Table 1.

Example 4

The difference from Example 1 is that the thickness of the MADN:DSA-Ph hole-transporting and light-emitting layer with a doping amount of 3wt% is 90nm. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency and CIE color coordinates of the diode were tested respectively, and the results are shown in Figure 9, wherein a in Figure 9 is the maximum luminous efficiency test chart, and b in Figure 9 is the maximum power efficiency test chart , c in Figure 9 is the maximum external quantum efficiency test chart, d in Figure 9 is the electroluminescence spectrum test chart, and the color coordinates are listed in Table 1.

Example 5

The difference from Example 3 is that the doping amount of DSA-Ph in the MADN:DSA-Ph hole-transporting and light-emitting layer is 1 wt%. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency and CIE color coordinates of the diode were tested respectively, and the results are shown in Figure 10, wherein a in Figure 10 is the maximum luminous efficiency test chart, and b in Figure 10 is the maximum power efficiency test chart , c in Figure 10 is the maximum external quantum efficiency test chart, d in Figure 10 is the electroluminescent spectrum test chart, and the color coordinates are listed in Table 1.

Example 6

The difference from Example 5 is that the doping amount of DSA-Ph in the MADN:DSA-Ph hole transport and light-emitting layer is 5 wt%. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency and CIE color coordinates of the diode were tested respectively, and the results are shown in Figure 11, wherein a in Figure 11 is the maximum luminous efficiency test chart, and b in Figure 11 is the maximum power efficiency test chart , c in Figure 11 is the maximum external quantum efficiency test chart, d in Figure 11 is the electroluminescence spectrum test chart, and the color coordinates are listed in Table 1.

Comparative example 1

A blue fluorescent organic light-emitting diode, which includes a 1mm-thick glass substrate, an ITO anode layer with a square resistance of 15Ω/□, a 30nm-thick PEDOT:PSS anode interface layer, and a 35nm-thick NPB hole Transport layer, 45nm-thick MADN:DSA-Ph emitting layer with a doping amount of 3wt%, 30nm-thick BPhen electron-transport layer, 0.7nm-thick LiF cathode interface layer and 100nm-thick Al cathode layer. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency, electroluminescence spectrum and color coordinates of the diode were tested respectively, and the results are shown in Figure 12, wherein a in Figure 12 is the maximum luminous efficiency test chart, and b in Figure 12 is the maximum Power efficiency test chart, c in Figure 12 is the maximum external quantum efficiency test chart, d in Figure 12 is the electroluminescence spectrum test chart, and the color coordinates are listed in Table 1.

Comparative example 2

The difference from Comparative Example 1 is that the hole transport layer is MADN with a thickness of 35 nm. The maximum luminous efficiency, maximum power efficiency, maximum external quantum efficiency and CIE color coordinates of the diode were tested respectively, and the results are shown in Figure 13, wherein a in Figure 13 is the maximum luminous efficiency test chart, and b in Figure 13 is the maximum power efficiency test chart , c in Figure 13 is the maximum external quantum efficiency test chart, d in Figure 13 is the electroluminescence spectrum test chart, and the color coordinates are listed in Table 1.

Comparative example 3

Existing documents: CHLiao, MTLee, CHTsai, CHChen, Highly efficient blueorganic light-emitting devices incorporating a composite hole transportlayer, the blue fluorescent organic light-emitting diode recorded in Appl.Phys.Lett.86(2005) 203507, its structure is: ITO/CF _x /[NPB:CuPc](40nm)/NPB(30nm)/[MADN:DSA-Ph](40nm)/Alq ₃ (10nm)/LiF(1nm)/Al(200nm), where, ITO is anode; CF _x is the anode interface layer; [NPB:CuPc](40nm)/NPB(30nm) is the double-layer hole transport layer; [MADN:DSA-Ph](40nm) is the blue fluorescent layer; Alq ₃ ( 10nm) is the electron transport layer; LiF (1nm) is the cathode interface layer; Al (200nm) is the cathode. The maximum luminous efficiency of the diode is 16.2cd/A, the maximum power efficiency is 7.9lm/W, the maximum external quantum efficiency is 8.7%, and the 1931CIE color coordinates are (0.15,0.29).

Comparative example 4

Existing literature: S. Yue, S. Zhang, Z. Zhang, Y. Wu, P. Wang, R. Guo, Y. Chen, D. Qu, Q. Wu, Y. Zhao, S. Liu, Improved power The blue fluorescent organic light-emitting diode described in efficiency of blue fluorescent organic light-emitting diode with intermixed host structure, J.Lumin.143(2013) 619, its structure is: ITO/NPB(40nm)/[NPB:DSA-Ph ](9nm)/[NPB:MADN:DSA-Ph](2nm)/[MADN:DSA-Ph](9nm)/BPhen(40nm)/LiF(1nm)/Al(100nm), where ITO is the anode; NPB (40nm) is a hole transport layer; [NPB:DSA-Ph](9nm)/[NPB:MADN:DSA-Ph](2nm)/[MADN:DSA-Ph](9nm) is a multilayer blue fluorescence Light-emitting layer; BPhen (40nm) is the electron transport layer; LiF (1nm) is the cathode interface layer; Al (100nm) is the cathode. The maximum luminous efficiency of the diode is 10.5cd/A, the maximum power efficiency is 8.7lm/W, and the 1931CIE color coordinates are (0.15,0.29).

According to the test results in Fig. 6 to Fig. 13, the blue fluorescent organic light emitting diodes prepared in Examples 1 to 6 with simple structure and high efficiency and the blue fluorescent organic light emitting diodes prepared in Comparative Example 1 and Comparative Example 2 The various performance data of the diodes in Comparative Example 3 and Comparative Example 4 are listed in Table 1 at the same time.

Table 1

It can be seen from Table 1 that the maximum luminous efficiency, maximum power efficiency, and maximum external quantum efficiency of the blue fluorescent organic light-emitting diodes prepared in Examples 1 to 6 are all higher than those of Comparative Example 1, Comparative Example 2 and Comparative Example 4, Both the maximum power efficiency and the maximum external quantum efficiency are higher than those of Comparative Example 3, wherein the blue fluorescent organic light-emitting diodes in Comparative Examples 1 to 4 all have multilayer complex structures. After comparison, it is found that the blue fluorescent organic light emitting diode with only a double-layer structure in the present invention has higher efficiency than the blue fluorescent organic light emitting diode with a multilayer complex structure.

Example 7

Verification of the hole transport ability of the MADN:DSA-Ph hole-transport and light-emitting layer with a doping amount of 3wt%

By constructing a single-hole device composed of NPB, MADN and MADN:DSA-Ph with a doping amount of 3wt%, and analyzing the three single-hole devices by current-voltage (IV) characteristics and impedance spectroscopy Analysis is carried out, and the analysis results are shown in Figure 14, wherein a in Figure 14 is the IV diagram of three kinds of single-hole devices, b in Figure 14 is the impedance-voltage (ZV) diagram of three kinds of single-hole devices, and c in Figure 14 is Phase Angle-Voltage of Three Single-hole Devices Fig. 14 d is the capacitance-voltage (CV) diagram of three kinds of single-hole devices.

The structures of the three single-hole devices are as follows:

Device H1:ITO/PEDOT:PSS/NPB(90nm)/Al(100nm)

Device H2: ITO/PEDOT:PSS/MADN(60nm)/NPB(30nm)/Al

Device H3:ITO/PEDOT:PSS/[MADN:DSA-Ph](60nm)/NPB(30nm)/Al

Among them, the 30 nm thick NPB in device H2 and device H3 acted as an electron blocking layer.

It can be seen from a in Figure 14 that at the same voltage, device H1 shows the highest current, followed by device H2 and device H3, indicating that MADN:DSA-Ph with a doping amount of 3wt% has the lowest hole mobility.

From Figure 14b and Figure 14c, it can be seen that the three single-hole devices have a high impedance of 10 ⁵ Ω and a phase of -90° at a low voltage (<1.3V), and all exhibit an insulating state. increase, all three hole-only devices show a semiconducting state, as a sharply decreasing impedance and a phase around 0° are observed. corresponding to the ZV graph and The transition voltages of the graphs increase in the order of device H1<device H2<device H3, which is sufficient to illustrate that the hole transport capabilities of the three single-hole devices gradually weaken in the same order.

It can be seen from d in Figure 14 that almost the same capacitance is observed at low voltage for the three hole-only devices, but as the voltage increases, the capacitance increases due to the accumulation of injected holes, and as the voltage is further increased, the observed When the capacitance peaks (shown by the arrow in the figure), it means that holes-electrons start to recombine. It can be seen from d in Figure 14 that the voltage corresponding to the peak value is device H1 (3.1V)<device H2 (6.1V ) < the sequence of device H3 (9.0 V) increased enough to indicate a gradual decrease in hole transport.

Comprehensive analysis of a, b, c, and d in Figure 14 shows that the hole mobility decreases in the order of μ _NPB > μ _MADN > μ _{3wt% MADN} :DSA-Ph.

In the present invention, in addition to being glass, the substrate can also be quartz or polyethylene terephthalate; the anode layer can also be Al ₂ O ₃ doped ZnO or fluorine doped SnO ₂ in addition to indium tin oxide. ; The anode interface layer can be MoO ₃ , WO ₃ or V ₂ O ₅ in addition to poly(3,4-ethylenedioxythiophene)-polystyrene sulfonic acid; the electron transport layer can be 4,7-diphenyl -1,10-phenanthroline, can also be 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 2,9-dimethyl-4,7-bis Benzene-1,10-phenanthroline, 2,2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole] or 3- (Biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole; in addition to LiF, the cathode interface layer can also be Cs ₂ CO ₃ or 8-hydroxyquinoline-lithium, the cathode can be Sm or Ca in addition to Al, and the same technical effect can be achieved after using the above materials for each functional layer.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in terms of form and Various changes may be made in the details without departing from the scope of the invention defined by the claims.

Claims (10)

1. A blue fluorescent organic light-emitting diode with simple structure and high efficiency, characterized in that, the diode includes a hole transport and light-emitting layer and an electron transport layer, and the hole transport and light-emitting layer is doped with 1- 4-bis-[4-(N,N-diphenyl)amino]styrylbenzene from 2-methyl-9,10-bis(2-naphthyl)anthracene. 2. A kind of blue fluorescent organic light-emitting diode with simple structure and high efficiency as claimed in claim 1, is characterized in that, described diode also comprises substrate, anode layer, anode interface layer, cathode interface layer and cathode layer; The substrate, the anode layer, the anode interface layer, the hole transport and light-emitting layer, the electron transport layer, the cathode interface layer and the cathode layer are sequentially stacked. 3. A blue fluorescent organic light-emitting diode with simple structure and high efficiency according to claim 1, wherein the substrate is made of glass, quartz or polyethylene terephthalate. 4. A blue fluorescent organic light-emitting diode with simple structure and high efficiency as claimed in claim 1, wherein the anode layer is made of indium tin oxide, Al ₂ O ₃ doped ZnO or fluorine doped made of SnO ₂ ; the cathode layer is made of Al, Sm or Ca. 5. A kind of blue fluorescent organic light-emitting diode with simple structure and high efficiency as claimed in claim 1, is characterized in that, described anode interface layer is made of poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate acid, MoO ₃ , WO ₃ or V ₂ O ₅ . 6. A kind of blue fluorescent organic light-emitting diode with simple structure and high efficiency as claimed in claim 1, is characterized in that, described electron transport layer is made of 4,7-diphenyl-1,10-phenanthroline, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline, 2, 2'-(1,3-phenyl)bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole] or 3-(biphenyl-4-yl)-5-( 4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole. 7. A kind of simple structure and high-efficiency blue fluorescent organic light-emitting diode as claimed in claim 1, it is characterized in that, described cathode interfacial layer is made of LiF, Cs ₂ CO ₃ or 8-hydroxyquinoline-lithium . 8. A blue fluorescent organic light-emitting diode with simple structure and high efficiency as claimed in any one of claims 1-7, wherein the 2-methyl-9,10-bis(2-naphthyl ) The doping amount of 1-4-di-[4-(N,N-diphenyl)amino]styrylbenzene in anthracene is 1-5wt%. 9 . The blue fluorescent organic light emitting diode with simple structure and high efficiency according to claim 8 , wherein the thickness of the hole transport and light emitting layer is 60-90 nm. 10. A blue fluorescent organic light-emitting diode with simple structure and high efficiency as claimed in claim 9, wherein the anode interface layer is poly(3,4-ethylenedioxythiophene)-polystyrenesulfonate The thickness is 20-40nm when it is acidic, the thickness is 0.5-15nm when the anode interface layer is MoO3, the thickness is _0.5-5nm when the anode interface layer is WO3, and the thickness is _0.5-5nm when the anode interface layer is _{V2O5 ;} The thickness of the transport layer is 20-50nm; when the cathode interface layer is LiF, the thickness is 0.5-1nm; when the cathode interface layer is _Cs2CO3 , the thickness is 1-20nm _; when the cathode interface layer is 8-hydroxyquinoline-lithium, the thickness is 1-5nm.