Display panel and display apparatus

Abstract

Disclosed in the present application are a display panel and a display apparatus. An organic light-emitting layer comprises a doped region and a non-doped region, wherein the non-doped region is located between the doped region and a hole barrier layer, and when the display panel is in a low-grayscale display state, an exciton concentration distribution curve of the organic light-emitting layer comprises a first crest located in the doped region and a second crest located in the non-doped region, a crest value of the second crest being less than a crest value of the first crest.

Description

Display panel and display device Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display panel and a display device. Background Art

[0002] Organic Light Emitting Display (OLED) has the characteristics of self-luminescence, fast response, and wide viewing angle. It has a very broad application prospect and has gradually replaced LCD in the display field.

[0003] An OLED display panel consists of a driver backplane and OLED light-emitting devices. The driver backplane adjusts the current flowing into the OLED light-emitting devices based on display requirements, turning them on or off. OLED light-emitting devices can emit light of varying wavelengths and brightness, creating different display images. As OLED light-emitting devices become more efficient, the current required to achieve the same brightness decreases. When displaying low-grayscale images, the current required to flow into the OLED light-emitting devices is even smaller.

[0004] When the required current becomes small to a certain extent and reaches the limit that the driver backplane can control, inaccurate current control will occur, resulting in uneven display of the OLED display panel when displaying low grayscale images. SUMMARY OF THE INVENTION

[0005] The embodiments of the present application provide a display panel and a display device, which can reduce the luminous efficiency of the light-emitting device layer at low grayscales to avoid the occurrence of uneven display due to inaccurate current control.

[0006] An embodiment of the present application provides a display panel, comprising a substrate, a thin film transistor layer disposed on the substrate, and a light emitting device layer disposed on a side of the thin film transistor layer away from the substrate;

[0007] The light emitting device layer includes:

[0008] an anode, disposed on a side of the thin film transistor layer away from the substrate;

[0009] an organic light-emitting layer, disposed on a side of the anode away from the thin film transistor layer;

[0010] a hole blocking layer, disposed on a side of the organic light-emitting layer away from the anode;

[0011] a cathode, disposed on a side of the hole blocking layer away from the organic light-emitting layer;

[0012] In which, the organic light-emitting layer includes a doped region and a non-doped region, and the non-doped region is located between the doped region and the hole blocking layer; when the display panel is in a low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer includes a first peak located in the doped region and a second peak located in the non-doped region, and the peak value of the second peak is smaller than the peak value of the first peak.

[0013] According to the above-mentioned object of the present application, an embodiment of the present application further provides a display device, the display device comprising a display panel, the display panel comprising a substrate, a thin film transistor layer disposed on the substrate, and a light emitting device layer disposed on a side of the thin film transistor layer away from the substrate;

[0014] The light emitting device layer includes:

[0015] an anode, disposed on a side of the thin film transistor layer away from the substrate;

[0016] an organic light-emitting layer, disposed on a side of the anode away from the thin film transistor layer;

[0017] a hole blocking layer, disposed on a side of the organic light-emitting layer away from the anode;

[0018] a cathode, disposed on a side of the hole blocking layer away from the organic light-emitting layer;

[0019] In which, the organic light-emitting layer includes a doped region and a non-doped region, and the non-doped region is located between the doped region and the hole blocking layer; when the display panel is in a low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer includes a first peak located in the doped region and a second peak located in the non-doped region, and the peak value of the second peak is smaller than the peak value of the first peak. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0021] FIG1 is a graph showing an exciton concentration distribution curve of an organic light-emitting layer under low grayscale display according to an embodiment of the present application;

[0022] FIG2 is a schematic structural diagram of a display panel provided in an embodiment of the present application;

[0023] FIG3 is a graph showing an exciton concentration distribution curve of an organic light-emitting layer under high grayscale display according to an embodiment of the present application;

[0024] 4 to 7 are schematic diagrams of a test process for an exciton concentration distribution curve of an organic light-emitting layer according to an embodiment of the present application;

[0025] FIG8 is a schematic diagram of an energy level distribution of a light-emitting device layer provided in an embodiment of the present application;

[0026] FIG9 is a schematic diagram of another energy level distribution of a light-emitting device layer provided in an embodiment of the present application;

[0027] FIG10 is another exciton concentration distribution curve of the organic light-emitting layer provided in an embodiment of the present application under low grayscale display;

[0028] FIG11 is another exciton concentration distribution curve diagram of the organic light-emitting layer provided in an embodiment of the present application under low grayscale display. Modes for Carrying Out the Invention

[0029] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0030] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0031] 1 and 2 , an embodiment of the present application provides a display panel including a substrate 10 , a thin film transistor layer 20 disposed on the substrate 10 , and a light emitting device layer 30 disposed on a side of the thin film transistor layer 20 away from the substrate 10 .

[0032] Among them, the light-emitting device layer 30 includes an anode 31, an organic light-emitting layer 32, a hole blocking layer 33 and a cathode 34; the anode 31 is arranged on the side of the thin film transistor layer 20 away from the substrate 10, the organic light-emitting layer 32 is arranged on the side of the anode 31 away from the thin film transistor layer 20, the hole blocking layer 33 is arranged on the side of the organic light-emitting layer 32 away from the anode 31, and the cathode 34 is arranged on the side of the hole blocking layer 33 away from the organic light-emitting layer 32.

[0033] Furthermore, the organic light-emitting layer 32 includes a doped region 321 and a non-doped region 322, and the non-doped region 322 is located between the doped region 321 and the hole blocking layer 33. When the display panel is in a low grayscale display state, the exciton concentration distribution curve 40 of the organic light-emitting layer 32 includes a first peak 41 located in the doped region 321 and a second peak 42 located in the non-doped region 322, and the peak value of the second peak 42 is smaller than the peak value of the first peak 41.

[0034] During the implementation of the application, the embodiment of the present application verified and calculated the exciton concentration distribution curve 40 of the organic light-emitting layer 32, and obtained that the organic light-emitting layer 32 has a first peak 41 and a second peak 42 in the exciton concentration distribution curve 40 at low grayscale, and the second peak 42 is on the side of the organic light-emitting layer 32 close to the hole blocking layer 33. Then, the embodiment of the present application sets the area corresponding to the second peak 42 to be undoped to form a non-doped area 322, thereby reducing the luminous efficiency of the light-emitting device layer 32 at low grayscale to avoid the occurrence of uneven display due to inaccurate current control.

[0035] Specifically, referring to FIG. 1 , FIG. 2 and FIG. 3 , the display panel provided in the embodiment of the present application includes a substrate 10 , a thin film transistor layer 20 and a light emitting device layer 30 .

[0036] Among them, the thin film transistor layer 20 is arranged on the substrate 10, and a plurality of thin film transistors, a plurality of scan lines and a plurality of data lines arranged in an array are formed on the thin film transistor layer 20, and the plurality of scan lines and the plurality of data lines intersect to form a plurality of pixel areas, and a thin film transistor is provided in each pixel area to transmit the transmission control signal into the pixel area. For example, the scan line can be connected to the gate of the thin film transistor, and the data line can be connected to the source of the thin film transistor, and then the thin film transistor transmits the data signal in the data line to the pixel area under the control of the scan line to realize the display function.

[0037] The light emitting device layer 30 is disposed on a side of the thin film transistor layer 20 away from the substrate 10 , and the light emitting device layer 30 includes a plurality of light emitting devices disposed corresponding to the plurality of pixel regions.

[0038] In one embodiment, each light-emitting device may include an anode 31, a hole transport layer 36, an electron blocking layer 37, an organic light-emitting layer 32, a hole blocking layer 33, an electron transport layer 35, and a cathode 34 arranged in sequence along the direction of the substrate 10 pointing to the thin film transistor layer 20.

[0039] In the embodiment of the present application, the organic light-emitting layer 32 includes a doped region 321 and a non-doped region 322 , and the non-doped region 322 is located between the doped region 321 and the hole blocking layer 33 , and the doped region 321 is located between the non-doped region 322 and the electron blocking layer 37 .

[0040] Among them, the organic light-emitting layer 32 includes a main material and a light-emitting guest material, and the light-emitting guest material is doped in the main material, thereby realizing the excitation light emission of the organic light-emitting layer 32. In the embodiment of the present application, the main material doped with the light-emitting guest material is provided in the doped region 321, and the main material not doped with the light-emitting guest material is provided in the non-doped region 322.

[0041] When the display panel is in a low grayscale display state, the exciton concentration distribution curve 40 of the organic light-emitting layer 32 includes a first peak 41 located in the doped region 321 and a second peak 42 located in the undoped region 322, and the peak value of the second peak 42 is smaller than the peak value of the first peak 41. This indicates that during low grayscale display, the organic light-emitting layer 32 can be excited to emit light in both the doped region 321 and the undoped region 322. However, in the embodiment of the present application, no luminescent guest material is provided in the undoped region 322. Therefore, the exciton recombination process to emit light does not occur in the undoped region 322, which can effectively reduce the luminous efficiency of the light-emitting device layer 30 in the low grayscale display state. Therefore, when displaying at low grayscale, a larger current input is required under the premise of maintaining the same luminous efficiency to avoid the current being reduced to a certain extent and reaching the control limit of the driving backplane, which may cause inaccurate current control. This effectively avoids unevenness of the display panel when displaying low grayscale images, thereby improving the display effect of the display panel at low grayscale.

[0042] In one embodiment, when the display panel is in a high grayscale display state, the exciton concentration distribution curve 40 of the organic light-emitting layer 32 includes a third peak 43 located in the doped area 321, and the highest height of the exciton concentration distribution curve of the organic light-emitting layer 32 in the non-doped area 322 is less than or equal to 10% of the height of the third peak 43. At this time, no peak is formed in the non-doped area 322 of the exciton concentration distribution curve 40, which indicates that when the display panel is in a high grayscale display, the doped area 321 of the organic light-emitting layer 32 can perform exciton recombination and emit light, while the organic light-emitting layer 32 cannot perform exciton recombination and emit light in the non-doped area 322. Therefore, even if the luminescent guest material is not provided in the non-doped area 322 in claim 1 of the present application, it will not affect the luminous efficiency of the display panel during high grayscale display, and the luminous effect of the display panel during high grayscale display can be guaranteed.

[0043] It should be noted that, referring to Figures 4 to 7 , the process of testing the exciton concentration distribution curve 40 of the organic light-emitting layer 32 in accordance with an embodiment of the present application is illustrated. The organic light-emitting layer 32 can be divided into a first region 1, a second region 2, a third region 3, and a fourth region 4, arranged sequentially from the electron blocking layer 37 toward the hole blocking layer 33. When the luminescent guest material is doped only in the organic light-emitting layer 32 corresponding to the first region 1, the second region 2, and the third region 3, as shown in Figures 4, 5, 6, and 7 , the efficiency of the light-emitting device at high and low current densities is very similar. This indicates that the exciton recombination areas in the first region 1, the second region 2, and the third region 3 are similar at high and low grayscales. This indicates that the exciton concentration distribution curve 40 forms first peaks 41 in the first region 1, the second region 2, and the third region 3 when the display panel is performing high and low grayscale displays. When the luminescent guest material is doped only in the organic light-emitting layer 32 corresponding to the fourth region 4, the low current density efficiency is significantly higher than the high current density, indicating that at low current density, there is a high exciton density distribution area in the fourth region 4, that is, when the display panel performs low grayscale display, the exciton concentration distribution curve 40 forms a second peak 42 in the fourth region 4.

[0044] As mentioned above, in the display panel provided in the embodiment of the present application, the doped region 321 in the organic light-emitting layer 32 can be regarded as a combination of the first region 1, the second region 2 and the third region 3, and the undoped region 322 can be regarded as the fourth region 4. Therefore, the embodiment of the present application verifies and measures the exciton concentration distribution curve 40 of the organic light-emitting layer 32, and obtains that the organic light-emitting layer 32 has a first peak 41 and a second peak 42 in the exciton concentration distribution curve 40 at low grayscale, and the second peak 42 is on the side of the organic light-emitting layer 32 close to the hole blocking layer 33. Therefore, the embodiment of the present application sets the area corresponding to the second peak 42 to be undoped to form the undoped region 322, thereby reducing the luminous efficiency of the light-emitting device layer 32 at low grayscale, thereby avoiding the occurrence of uneven display due to inaccurate current control. At the same time, since the exciton concentration distribution curve 40 does not have a peak in the undoped region 322 when the display panel displays at high grayscale, the setting of the undoped region 322 will not affect the luminous efficiency of the display panel when displaying at high grayscale.

[0045] Furthermore, the embodiment of the present application designs the energy level distribution and thickness of the hole transport layer 36, the electron blocking layer 37, the organic light-emitting layer 32, the hole blocking layer 33 and the electron transport layer 35 so that the exciton concentration distribution curve 40 of the organic light-emitting layer 32 forms a distribution of a first peak 41, a second peak 42 and a third peak 43.

[0046] Referring to Figure 8, in one embodiment of the present application, the HOMO energy level of the hole transport layer 36 is greater than or equal to the HOMO energy level of the electron blocking layer 37, and the absolute value of the difference between the HOMO energy level of the hole transport layer 36 and the HOMO energy level of the electron blocking layer 37 is less than or equal to 0.1eV; the HOMO energy level of the electron blocking layer 37 is less than or equal to the HOMO energy level of the main material in the organic light-emitting layer 32, and the absolute value of the difference between the HOMO energy level of the electron blocking layer 37 and the HOMO energy level of the main material in the organic light-emitting layer 32 is less than or equal to 0.2eV, so as to promote hole injection.

[0047] The LUMO energy level of the hole blocking layer 33 is greater than the LUMO energy level of the electron transport layer 35, and the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the LUMO energy level of the electron transport layer 35 is greater than or equal to 0.1 eV and less than or equal to 0.3 eV; the LUMO energy level of the hole blocking layer 33 is greater than the HOMO energy level of the main material in the organic light-emitting layer 32, and the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32 is greater than or equal to 0.1 eV and less than or equal to 0.3 eV; the LUMO energy level of the main material in the organic light-emitting layer 32 is greater than the LUMO energy level of the electron transport layer 35 to weaken the injection of electrons.

[0048] Furthermore, the absolute value of the difference between the HOMO energy level of the electron blocking layer 37 and the HOMO energy level of the main material in the organic light-emitting layer 32 is smaller than the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32, so as to achieve the purpose of enhancing hole injection and weakening electron injection in the light-emitting device, thereby achieving the exciton concentration distribution curve 40 in the low grayscale display state. The first peak 41 located in the doped area 321 and the second peak 42 located in the non-doped area 322 can be formed, and the peak value of the second peak 42 is smaller than the peak value of the first peak 41.

[0049] Referring to Figure 9, in another embodiment of the present application, the HOMO energy level of the hole transport layer 36, the HOMO energy level of the electron blocking layer 37, and the HOMO energy level of the main material in the organic light-emitting layer 32 are arranged in a stepped manner. For example, the HOMO energy level of the hole transport layer 36 is greater than the HOMO energy level of the electron blocking layer 37, and the HOMO energy level of the electron blocking layer 37 is greater than the HOMO energy level of the main material in the organic light-emitting layer 32. The absolute value of the energy level difference between adjacent film layers is less than or equal to 0.1 eV to promote hole injection.

[0050] The LUMO energy level of the hole blocking layer 33 is greater than the LUMO energy level of the electron transport layer 35, and the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the LUMO energy level of the electron transport layer 35 is greater than or equal to 0.1 eV and less than or equal to 0.3 eV; the LUMO energy level of the hole blocking layer 33 is greater than the HOMO energy level of the main material in the organic light-emitting layer 32, and the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32 is greater than or equal to 0.1 eV and less than or equal to 0.3 eV; the LUMO energy level of the main material in the organic light-emitting layer 32 is greater than the LUMO energy level of the electron transport layer 35 to weaken the injection of electrons.

[0051] Furthermore, the absolute value of the difference between the HOMO energy level of the electron blocking layer 37 and the HOMO energy level of the main material in the organic light-emitting layer 32 is smaller than the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32, so as to achieve the purpose of enhancing hole injection and weakening electron injection in the light-emitting device, thereby achieving the exciton concentration distribution curve 40 in the low grayscale display state. The first peak 41 located in the doped area 321 and the second peak 42 located in the non-doped area 322 can be formed, and the peak value of the second peak 42 is smaller than the peak value of the first peak 41.

[0052] It should be noted that in the embodiment of the present application, due to the provision of the hole blocking layer 33, a larger energy level barrier can be formed between the organic light-emitting layer 32 and the electron transport layer 35, which in turn provides a basis for enhancing hole injection and weakening electron injection, as well as forming an exciton concentration distribution curve 40 having a first peak 41 and a second peak 42.

[0053] In the implementation of the present application, when the LUMO energy level of the hole blocking layer 33 becomes larger, the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32 becomes larger, so that the carrier balance in the organic light-emitting layer 32 is biased towards hole excess. At this time, the thickness of the organic light-emitting layer 32 in the non-doped area 322 can be reduced; when the LUMO energy level of the hole blocking layer 33 becomes smaller, the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32 is reduced, so that the carrier balance in the organic light-emitting layer 32 is biased towards electron excess. At this time, the thickness of the organic light-emitting layer 32 in the non-doped area 322 can be increased.

[0054] The thickness of the organic light-emitting layer 32 in the non-doped region 322 decreases as the LUMO energy level of the hole blocking layer 33 increases; the thickness of the organic light-emitting layer 32 in the non-doped region 322 increases as the LUMO energy level of the hole blocking layer 33 decreases.

[0055] In one embodiment, the ratio of the thickness of the organic light-emitting layer 32 in the non-doped region 322 to the total thickness of the organic light-emitting layer 32 is greater than 0% and less than or equal to 60%. Specifically, the thickness of the organic light-emitting layer 32 in the non-doped region 322 and the LUMO energy level of the hole blocking layer 33 can satisfy the following conditions:

[0056] In one embodiment, the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the main material in the organic light-emitting layer 32 is greater than or equal to 0.1eV and less than or equal to 0.3eV. At this time, the carrier balance in the organic light-emitting layer 32 is good, and the ratio of the thickness of the organic light-emitting layer 32 in the non-doped region 322 to the thickness of the organic light-emitting layer 32 is greater than or equal to 10% and less than or equal to 20%.

[0057] In one embodiment, the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the host material in the organic light-emitting layer 32 is greater than 0.3 eV. In this case, the carrier balance in the organic light-emitting layer 32 is biased toward a hole excess. The absolute value of the ratio of the thickness of the organic light-emitting layer 32 in the undoped region 322 to the thickness of the organic light-emitting layer 32 is greater than or equal to 2% and less than 10%. Furthermore, referring to FIG10 , when the display panel is in a low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer 32 further includes: a first valley 44 located between a first peak 41 and a second peak 42; the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the host material in the organic light-emitting layer 32 is greater than 0.3 eV, and the contact cross-section between the doped region 321 and the undoped region 322 is located between the first valley 44 and the second peak 42.

[0058] In one embodiment, the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the host material in the organic light-emitting layer 32 is less than 0.1 eV. In this case, the carrier balance in the organic light-emitting layer 32 is biased toward electron excess, and the ratio of the thickness of the organic light-emitting layer 32 in the undoped region 322 to the total thickness of the organic light-emitting layer 32 is greater than 20% and less than or equal to 30%. Furthermore, referring to FIG11 , when the display panel is in a low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer 32 further includes: a second valley 45 located between the first peak 41 and the second peak 42; the absolute value of the difference between the LUMO energy level of the hole blocking layer 33 and the HOMO energy level of the host material in the organic light-emitting layer 32 is less than 0.1 eV, and the contact cross-section between the doped region 321 and the undoped region 322 is located between the second valley 45 and the first peak 41.

[0059] Furthermore, in the embodiment of the present application, the position of the organic light-emitting layer 32 in the non-doped region 322 is adjusted and tested to verify the luminous efficiency of the light-emitting device when the non-doped region 322 is at different positions in the organic light-emitting layer 32 .

[0060] The present application provides comparative examples, namely, Example 1 to Example 3, wherein the organic light-emitting layer 32 in the comparative examples is a uniformly doped film layer.

[0061] In the first embodiment, the thickness of the non-doped region 322 in the organic light-emitting layer 32 is 5 nm. The non-doped region 322 is located on a side of the organic light-emitting layer 32 close to the hole blocking layer 33 and is connected to the hole blocking layer 33 .

[0062] In the second embodiment, the thickness of the non-doped region 322 in the organic light-emitting layer 32 is 5 nanometers, and the non-doped region 322 is located in the middle of the organic light-emitting layer 32 .

[0063] In the third embodiment, the thickness of the non-doped region 322 in the organic light-emitting layer 32 is 5 nm. The non-doped region 322 is located on a side of the organic light-emitting layer 32 close to the electron blocking layer 37 and is connected to the electron blocking layer 37 .

[0064] The manufacturing process of the light-emitting device in the embodiment of the present application includes:

[0065] The anode 31 is made of ITO, the hole transport layer 36 is made of NPB and has a thickness of 120 nm, the electron blocking layer 37 is made of TCTA and has a thickness of 40 nm, the organic light-emitting layer 32 is 40 nm thick, the host material is mCBP, the luminescent guest material is Ir(ppy)3, and the doping concentration of the luminescent guest material in the host material is 6%, the electron transport layer 35 is made of TPBi and has a thickness of 35 nm, and the cathode 34 is a Mg:Ag (1:10) mixed electrode and has a thickness of 12 nm. During device fabrication, the organic material is deposited at a rate of 1 A / s, and the metal material at a rate of 2 A / s. The chemical structures of the above organic materials are shown below:

[0066]

[0067] It can be understood that in each embodiment, the positions and thicknesses of the doped region 321 and the non-doped region 322 in the organic light-emitting layer 32 are set differently to obtain the first, second and third embodiments.

[0068] The present invention calculates the luminous efficiency of the light-emitting devices in the comparative example, examples 1, 2 and 3 at brightness of 0.5 nits, 2 nits, 10 nits, 2000 nits and 20000 nits respectively, and records them as CE 0.5 ,CE2.0 ,CE 10 ,CE 2k , and CE 20k When the brightness of the light emitting device is less than or equal to 10 nits, the display panel can be considered to be in a low grayscale display state, and the test calculation results are shown in Table 1 below.

[0069] Table 1

[0070] Voltage@J10LT95@J50CE0.5CE2.0CE10CE2kCE20kComparative Example3.4589166175172170167Example 13.478889124156169164Example 23.4379126131135134128Example 33.458010510710610295

[0071] Among them, J10 and J50 represent the current density of 10mA / cm 3 LT95 represents the time it takes for the brightness to decay to 95% of the initial brightness, and the unit is hours.

[0072] As can be seen from Table 1, Example 1 can reduce the luminous efficiency of the light-emitting device in the low grayscale display state, and maintain the luminous efficiency of the light-emitting device in the high grayscale display state. That is, when the non-doped region 322 is located on the side of the organic light-emitting layer 32 close to the hole blocking layer 33, it can meet the requirements of reducing the luminous efficiency of the light-emitting device in the low grayscale display state and maintaining the luminous efficiency of the light-emitting device in the high grayscale display state. This can effectively avoid the occurrence of uneven display due to inaccurate current control, and can also avoid affecting the luminous efficiency of the display panel in the high grayscale display state.

[0073] Furthermore, the embodiment of the present application also adjusts and tests the thickness of the organic light-emitting layer 32 in the non-doped region 322 to verify the luminous efficiency of the light-emitting device when the thickness of the non-doped region 322 in the organic light-emitting layer 32 is different.

[0074] The present application provides embodiments 4 to 8. It should be noted that in embodiments 4 to 8, the non-doped region 322 is located on the side of the organic light-emitting layer 32 close to the hole blocking layer 33 .

[0075] In Example 4, the thickness of the organic light-emitting layer 32 in the non-doped area 322 is 1 nanometer; in Example 5, the thickness of the organic light-emitting layer 32 in the non-doped area 322 is 3 nanometers; in Example 6, the thickness of the organic light-emitting layer 32 in the non-doped area 322 is 7 nanometers; in Example 7, the thickness of the organic light-emitting layer 32 in the non-doped area 322 is 10 nanometers; in Example 8, the thickness of the organic light-emitting layer 32 in the non-doped area 322 is 20 nanometers, and the test calculations are shown in Table 2 below.

[0076] Table 2

[0077] Voltage @J10LT95@J50CE0.5CE2.0CE10CE2kCE20kComparative Example 3.4589166175172170167Example 4 3.4587168173174171168Example 5 3.4888101146160168165Example 2 3.478889124156169164Example 6 3.468285120149169164Example 7 3.507579115140164160Example 8 3.55407079818277

[0078] As shown in Table 2, as the thickness of the organic light-emitting layer 32 in the undoped region 322 increases, the low-grayscale efficiency gradually decreases. When the thickness of the organic light-emitting layer 32 in the undoped region 322 exceeds 10 nm, the high-grayscale efficiency also begins to be affected. When the thickness of the organic light-emitting layer 32 in the undoped region 322 is less than 3 nm, the effect of regulating the low-grayscale efficiency is limited. Therefore, the thickness of the organic light-emitting layer 32 in the undoped region 322 is greater than or equal to 3 nm and less than or equal to 10 nm to meet the requirement of reducing the luminous efficiency at low grayscales without affecting the luminous efficiency at high grayscales.

[0079] To sum up, the embodiment of the present application sets a non-doped area 322 on the side of the organic light-emitting layer 32 close to the hole blocking layer 33, and no light-emitting guest material is set in the non-doped area 322, so that the process of exciton recombination and light emission will not occur in the non-doped area 322, which can effectively reduce the luminous efficiency of the light-emitting device layer 30 in the low grayscale display state. In the low grayscale display state, under the premise of the same luminous efficiency, a larger current input is required to avoid the current being too small to a certain extent and reaching the limit that the driving backplane can control, resulting in inaccurate current control, thereby effectively avoiding unevenness of the display panel in low grayscale images, thereby improving the display effect of the display panel in low grayscale; at the same time, it will not affect the luminous efficiency of the display panel in high grayscale images.

[0080] In addition, an embodiment of the present application further provides a display device, which includes the display panel described in the above embodiment.

[0081] Since the display device provided in the embodiment of the present application has the same display panel as that in the above embodiment, the display device has the same beneficial effects as the display panel described in the above embodiment, which will not be described in detail here.

[0082] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0083] The above is a detailed introduction to a display panel and a display device provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A display panel, comprising a substrate, a thin film transistor layer disposed on the substrate, and a light emitting device layer disposed on a side of the thin film transistor layer away from the substrate; The light emitting device layer comprises: an anode, disposed on a side of the thin film transistor layer away from the substrate; An organic light-emitting layer is arranged on a side of the anode away from the thin film transistor layer; A hole blocking layer, disposed on a side of the organic light-emitting layer away from the anode; A cathode, disposed on a side of the hole blocking layer away from the organic light-emitting layer; Wherein, the organic light-emitting layer includes a doped region and a non-doped region, and the non-doped region is located between the doped region and the hole blocking layer; when the display panel is in a low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer includes a first peak located in the doped region, and a second peak located in the non-doped region, and the peak value of the second peak is smaller than the peak value of the first peak.

2. The display panel according to claim 1, wherein: The organic light-emitting layer includes a main material, and the light-emitting device layer also includes an electron transport layer arranged between the hole blocking layer and the cathode, the LUMO energy level of the hole blocking layer is greater than the HOMO energy level of the main material, and the LUMO energy level of the hole blocking layer is greater than the LUMO energy level of the electron transport layer.

3. The display panel according to claim 2, wherein: The light emitting device layer further includes an electron blocking layer disposed between the organic light emitting layer and the anode, and a HOMO energy level of the electron blocking layer is less than or equal to a HOMO energy level of the host material.

4. The display panel according to claim 3, wherein: An absolute value of a difference between a HOMO energy level of the electron blocking layer and a HOMO energy level of the host material is smaller than an absolute value of a difference between a LUMO energy level of the hole blocking layer and a HOMO energy level of the host material.

5. The display panel according to claim 3, wherein: An absolute value of a difference between a HOMO energy level of the electron blocking layer and a HOMO energy level of the host material is less than or equal to 0.2 eV.

6. The display panel according to claim 2, wherein: The absolute value of the difference between the LUMO energy level of the hole blocking layer and the HOMO energy level of the main material is greater than or equal to 0.1eV and less than or equal to 0.3eV, and the ratio of the thickness of the organic light-emitting layer in the non-doped area to the thickness of the organic light-emitting layer is greater than or equal to 10% and less than or equal to 20%.

7. The display panel according to claim 2, wherein: The absolute value of the difference between the LUMO energy level of the hole blocking layer and the HOMO energy level of the main material is greater than 0.3 eV, and the ratio of the thickness of the organic light-emitting layer in the non-doped area to the thickness of the organic light-emitting layer is greater than or equal to 2% and less than 10%.

8. The display panel according to claim 7, wherein: When the display panel is in the low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer further includes: a first wave valley located between the first wave peak and the second wave peak; An absolute value of a difference between a LUMO energy level of the hole blocking layer and a HOMO energy level of the host material is greater than 0.3 eV, and a contact cross section between the doped region and the non-doped region is between the first wave valley and the second wave peak.

9. The display panel according to claim 2, wherein: The absolute value of the difference between the LUMO energy level of the hole blocking layer and the HOMO energy level of the main material is less than 0.1 eV, and the ratio of the thickness of the organic light-emitting layer in the non-doped area to the thickness of the organic light-emitting layer is greater than 20% and less than or equal to 30%.

10. The display panel according to claim 9, wherein: When the display panel is in the low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer further includes: a second wave valley located between the first wave peak and the second wave peak; An absolute value of a difference between a LUMO energy level of the hole blocking layer and a HOMO energy level of the host material is less than 0.1 eV, and a contact cross section between the doped region and the non-doped region is between the second wave valley and the first wave peak.

11. The display panel according to claim 1, wherein: The thickness of the organic light-emitting layer in the non-doped region decreases as the LUMO energy level of the hole blocking layer increases.

12. The display panel according to claim 1, wherein: The thickness of the organic light-emitting layer in the non-doped region increases as the LUMO energy level of the hole blocking layer decreases.

13. The display panel according to claim 1, wherein: A ratio of the thickness of the organic light-emitting layer in the non-doped region to the thickness of the organic light-emitting layer is greater than 0% and less than or equal to 60%.

14. The display panel according to claim 1, wherein: The thickness of the organic light-emitting layer in the non-doped region is greater than or equal to 3 nanometers and less than or equal to 10 nanometers.

15. The display panel according to claim 1, wherein: The organic light-emitting layer further includes a light-emitting guest material, and the host material is disposed in the doping region and the non-doping region, and the light-emitting guest material is disposed in the doping region.

16. The display panel according to claim 1, wherein: When the display panel is in a high grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer includes a third peak located in the doped area, and the highest height of the exciton concentration distribution curve of the organic light-emitting layer in the non-doped area is less than or equal to 10% of the height of the third peak.

17. A display device, comprising a display panel, wherein the display panel comprises a substrate, a thin film transistor layer disposed on the substrate, and a light emitting device layer disposed on a side of the thin film transistor layer away from the substrate; The light emitting device layer comprises: an anode, disposed on a side of the thin film transistor layer away from the substrate; An organic light-emitting layer is arranged on a side of the anode away from the thin film transistor layer; A hole blocking layer, disposed on a side of the organic light-emitting layer away from the anode; A cathode, disposed on a side of the hole blocking layer away from the organic light-emitting layer; Wherein, the organic light-emitting layer includes a doped region and a non-doped region, and the non-doped region is located between the doped region and the hole blocking layer; when the display panel is in a low grayscale display state, the exciton concentration distribution curve of the organic light-emitting layer includes a first peak located in the doped region, and a second peak located in the non-doped region, and the peak value of the second peak is smaller than the peak value of the first peak.

18. The display device according to claim 17, wherein: The organic light-emitting layer includes a main material, and the light-emitting device layer also includes an electron transport layer arranged between the hole blocking layer and the cathode, the LUMO energy level of the hole blocking layer is greater than the HOMO energy level of the main material, and the LUMO energy level of the hole blocking layer is greater than the LUMO energy level of the electron transport layer.

19. The display device according to claim 18, wherein: The light emitting device layer further includes an electron blocking layer disposed between the organic light emitting layer and the anode, and a HOMO energy level of the electron blocking layer is less than or equal to a HOMO energy level of the host material.

20. The display device according to claim 19, wherein: An absolute value of a difference between a HOMO energy level of the electron blocking layer and a HOMO energy level of the host material is smaller than an absolute value of a difference between a LUMO energy level of the hole blocking layer and a HOMO energy level of the host material.

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