A method for producing a color temperature adjustable organic white light illumination panel

Abstract

The application discloses a color temperature adjustable organic white light illuminating panel and a preparation method thereof, and belongs to the technical field of organic electroluminescence. The panel comprises a substrate, a first electrode layer, a second electrode layer and a plurality of normal and inverted subunits between the two. The normal and inverted subunits both comprise a yellow light emitting layer and a blue light emitting layer, which are respectively composed of a host material and a guest material. The functional layers of the normal and inverted subunits comprise a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer, which are all separated from each other in structure. The panel is driven by an alternating current power supply, and the combination of the normal and inverted subunits realizes independent adjustment of brightness and color temperature. The preparation method comprises steps such as cleaning, drying and vacuum evaporation. The application solves the problem that the color temperature and brightness are difficult to be independently controlled in the existing OLED device, and has simple device structure, excellent performance and application in the field of intelligent lighting.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic electroluminescence, in particular to a preparation method of an organic white light illumination panel with adjustable color temperature. BACKGROUND

[0002] Smart lighting systems are able to adjust the ambient color temperature according to the user's preferences, and therefore have received extensive attention. A key feature of these systems is that they can independently control the spectrum and intensity of light, which makes them indispensable for creating a human-centered environment that will have a positive impact on people's physical and mental health. White organic light-emitting diodes (OLEDs) are becoming promising candidates for the next generation of lighting due to their excellent flexibility, lightweight nature and lower production cost. Their ability to emit light over a wide spectral range and precisely adjust the intensity meets the requirements of smart lighting, positioning them as the main choice for future applications.

[0003] However, there are currently three methods for color temperature adjustable organic white light emitting devices. The first is multiple light-emitting layers in OLEDs, which faces the challenge of independent control of spectrum and brightness. The second method is to vertically stack multiple OLEDs with a semi-transparent intermediate electrode to solve this problem, which requires additional control logic to optimize the current distribution, making the driving circuit and control process complex. The third method is to arrange complementary color OLEDs horizontally, but the narrow gap between the electrodes makes them susceptible to leakage current from growth defects. The high aspect ratio of the strip electrodes also increases the series resistance, limiting brightness and power efficiency.

[0004] Therefore, how to provide an organic white light illumination panel with good device performance that can independently adjust brightness and color temperature, and a preparation method thereof is a problem that those skilled in the art need to solve. SUMMARY

[0005] Therefore, the present application provides an organic white light illumination panel with adjustable color temperature and a preparation method thereof, which can independently adjust the color temperature and brightness by AC driving only.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] An organic white light illumination panel with adjustable color temperature, the organic white light illumination panel comprises a substrate from bottom to top, a first electrode layer, a second electrode layer;

[0008] The first electrode layer and the second electrode layer are a plurality of upright sub-units and a plurality of inverted sub-units;

[0009] The normal subunit comprises, from bottom to top, a first hole injection layer, a first hole transport layer, a first light emitting layer, a second light emitting layer, a first electron transport layer, and a first electron injection layer.

[0010] The inverted subunit comprises, from bottom to top, a second electron injection layer, a second electron transport layer, a first light emitting layer, a second light emitting layer, a second hole transport layer, and a second hole injection layer.

[0011] The normal subunit and the inverted subunit jointly comprise the first light emitting layer and the second light emitting layer.

[0012] The first hole injection layer and the second electron injection layer are separated from each other in structure.

[0013] The first hole transport layer and the second electron transport layer are separated from each other in structure.

[0014] The first electron transport layer and the second hole transport layer are separated from each other in structure.

[0015] The first electron injection layer and the second hole injection layer are separated from each other in structure.

[0016] The first electrode layer and the second electrode layer are connected together by an alternating current power supply.

[0017] Further, the substrate is glass or a polymer.

[0018] Further, the polymer is polyimide or polyethylene naphthalate.

[0019] Further, the substrate has a transmittance greater than 20% in the visible light range.

[0020] The design of using glass or polyimide or polyethylene naphthalate as the substrate is mainly used to enhance the light transmittance and mechanical stability of the organic white light illumination panel, and the components ensure that the transmittance of the substrate is greater than 20% in the visible light range through synergistic effect, thereby providing stable foundation support for color temperature adjustment and light efficiency output of the panel.

[0021] Further, the planar size of the normal subunit and the inverted subunit is 300 μm x 300 μm to 1000 μm x 1000 μm, and the unit gap is 100 to 500 μm.

[0022] Further, the first light emitting layer and the second light emitting layer are a yellow light emitting layer and a blue light emitting layer, respectively.

[0023] Further, the yellow light emitting layer and the blue light emitting layer are composed of a host material and a guest material.

[0024] Further, the host material of the yellow light-emitting layer is 4,4'-bis(9-carbazole) biphenyl (CBP), and the guest material of the yellow light-emitting layer is di(4-phenyl-thiophene[3,2-c]pyridine-C2,N) iridium (III) acetylacetone acid (PO-01);

[0025] Further, the host material of the blue light-emitting layer is 4,4',4'-tris(9-carbazole-9-yl) triphenylamine (TCTA), and the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2) iridium picolinoyl (FIrPic);

[0026] Further, the doping mass ratio between the host material and the guest material is (20~1):1.

[0027] The present application adopts the design of upright sub-units and inverted sub-units, which is mainly used to enhance the color temperature adjustment performance of the organic white light illumination panel. The precise design of the planar size and gap of the upright sub-units and the inverted sub-units ensures the light-emitting uniformity and structural stability. The yellow light-emitting layer is formed by 4,4'-bis(9-carbazole) biphenyl (CBP) and di(4-phenyl-thiophene[3,2-c]pyridine-C2,N) iridium (III) acetylacetone acid (PO-01), and the blue light-emitting layer is composed of 4,4',4'-tris(9-carbazole-9-yl) triphenylamine (TCTA) and bis(4,6-difluorophenylpyridine-N,C2) iridium picolinoyl (FIrPic). The balance of the spectrum and the controllable adjustment of the color temperature are realized by optimizing the doping ratio of the host material and the guest material of the two light-emitting layers. The components cooperate with each other in structure, further improving the light efficiency output and stability of the panel.

[0028] Further, the second electron injection layer is 4,7-diphenyl-1,10-phenanthroline (Bphen) doped with magnesium, and the mass ratio of 4,7-diphenyl-1,10-phenanthroline to magnesium is (50~2):1.

[0029] Further, the first electrode layer is an indium tin oxide electrode with a transmittance greater than 50% in the visible light range.

[0030] Further, the thickness of the first electrode layer is 10~500nm;

[0031] Further, the first hole transport layer and the second hole transport layer are equal-thickness transport layers with a thickness of 20~100nm;

[0032] Further, the first electron transport layer and the second electron transport layer are equal-thickness transport layers with a thickness of 20~100nm;

[0033] Further, the first light-emitting layer and the second light-emitting layer are equal-thickness light-emitting layers with a thickness of 20~100nm;

[0034] Further, the first and second electron injection layers are equal-thickness injection layers with a thickness of 5-30nm.

[0035] Further, the second electrode layer is made of metal aluminum or metal silver with a thickness of 10-200nm.

[0036] The functional layer optimization design of the present application is mainly used for enhancing the light efficiency output and structural stability of the organic white light illumination panel, the second electron injection layer is formed by 4,7-diphenyl-1,10-phenanthroline (Bphen) doped magnesium, the electron injection efficiency is improved by adjusting the mass ratio, the first electrode layer is an indium tin oxide electrode with high light transmission performance and cooperates with the hole transport layer, the electron transport layer and the light emitting layer with equal-thickness design to effectively balance the carrier transport and light output, the thickness optimization of the first and second electron injection layers further improves the interface injection effect, the second electrode layer is composed of metal aluminum or metal silver to ensure the conductivity and stability, and the precise design of each component improves the photoelectric conversion efficiency and service life of the panel.

[0037] Further, the first and second hole injection layers are 4,4'-cyclohexyl di[N,N-di(4-methylphenyl) aniline] (TAPC).

[0038] Further, the first hole transport layer is 4,4',4'-tris(carbazole-9-yl) triphenylamine (TCTA), and the second electron transport layer is 4,7-diphenyl-1,10-phenanthroline (Bphen).

[0039] Further, the first electron transport layer and the first electron injection layer are 3,3'-[5'-[3-(3-pyridyl) phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB).

[0040] The application adopts multi-functional layer cooperative design and is mainly used for enhancing the carrier injection and transmission performance of an organic white light illumination panel, the first hole injection layer and the second hole injection layer are composed of 4,4'-cyclohexyl di-N,N-di(4-methylphenyl) aniline, high-efficiency hole injection is provided, the first hole transport layer is composed of 4,4',4'-tris(carbazole-9-yl) triphenylamine (TCTA), and the second electron transport layer 4,7-diphenyl-1,10-phenanthroline (Bphen) cooperatively optimizes the balanced transmission of holes and electrons, the first electron transport layer and the first electron injection layer are composed of 3,3'-[5'-[3-(3-pyridyl) phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB), and the electron injection efficiency is improved, and through accurate material selection and interlayer matching, the high-efficiency injection and uniform distribution of carriers in the device are realized, so that the light-emitting performance and stability of the panel are significantly improved.

[0041] The application further provides a preparation method of the organic white light illumination panel with adjustable color temperature.

[0042] Step S1: the surface of the first electrode layer located on the substrate is cleaned by a Decon 90 alkaline cleaning solution, and deionized water is used for ultrasonic cleaning three times, each time for 5-30 min; after cleaning, the water on the surface of the substrate is removed by nitrogen, and heating and drying are performed, the drying temperature is 100-200 DEG C, the drying time is 10-60 min, and after drying, oxygen plasma treatment is performed for 5-20 min;

[0043] Step S2: the substrate and the first electrode layer treated in step 1 are placed into a multi-source organic molecular vapor deposition system, and vacuumized to 6*10 -4 Pa, the first hole injection layer and the first hole transport layer are evaporated on the first electrode layer by a positive subunit precision metal mask plate;

[0044] Step S3: the positive subunit precision metal mask plate is replaced, and the second electron injection layer and the second electron transport layer are evaporated on the first electrode layer in sequence;

[0045] Step S4: a large-area mask plate is replaced, and the first light-emitting layer and the second light-emitting layer are evaporated on the first hole transport layer and the second electron transport layer in sequence;

[0046] Step S5: the positive subunit precision metal mask plate is replaced, and the first electron transport layer and the first electron injection layer are evaporated on the second light-emitting layer in sequence;

[0047] Step S6: the inverted subunit precision metal mask plate is replaced, and the second hole transport layer and the second hole injection layer are evaporated on the second light-emitting layer in sequence;

[0048] Step S7: replace the metal electrode mask, and evaporate a second metal electrode on the first electron injection layer and the second hole injection layer.

[0049] The application adopts a preparation method of step-by-step evaporation to design a structure mainly used for enhancing the structural precision and light-emitting performance of an organic white light illumination panel. The surface cleanliness and activity of the substrate and the first electrode layer are ensured by Decon 90 alkaline cleaning solution and oxygen plasma treatment, which provides reliable guarantee for the attachment of subsequent functional layers. The evaporation of the normal functional layer, the inverted functional layer and the light-emitting functional layer realizes the precise positioning and thickness control between layers through a precise metal mask. The evaporation of the first hole injection layer and the second electron injection layer optimizes the injection efficiency of holes and electrons. The synergistic effect of each functional layer improves the carrier balanced transport performance. Finally, a stable device structure is formed by evaporating a second metal electrode. The step design ensures the efficient light emission and stability of the panel. Advantages

[0050] 1. The application improves the light transmission performance and mechanical stability of the organic white light illumination panel by using glass or polyimide, polyethylene naphthalate as the substrate. Compared with the prior art, the accuracy of color temperature adjustment and the stability of light efficiency output are significantly improved. The precise design of the normal sub-unit and the inverted sub-unit realizes the light-emitting uniformity. The yellow light-emitting layer and the blue light-emitting layer are optimized by the synergistic doping of the host material and the guest material, which ensures the spectral balance and the controllability of color temperature. The optimized design of the functional layer, such as the Bphen-doped magnesium electron injection layer and the high light transmission performance of the indium tin oxide electrode, cooperates with the hole transport layer, the electron transport layer and the light-emitting layer with equal thickness design, which not only improves the carrier transport efficiency, but also enhances the photoelectric conversion performance. The precise proportioning and thickness control of each component ensure the structural stability and long service life. This design effectively solves the pain point that the color temperature and brightness are difficult to be independently adjusted in the prior art, promotes the development of the intelligent lighting field, and has broad application prospect and irreplaceable advantages.

[0051] 2.The organic white light illumination panel of the present application significantly improves the carrier injection efficiency, transmission balance and light emission stability of the organic white light illumination panel through the synergistic design of the multifunctional layer and the precise preparation process. Compared with the prior art, the innovation lies in the use of 4,4'-cyclohexyl di-N,N-di(4-methylphenyl) aniline and 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB) and other materials, which optimizes the hole and electron injection through precise proportioning and interlayer matching, solving the problems of uneven carrier distribution and low light emission efficiency in the prior art. The step-by-step evaporation process combined with Decon90 cleaning and oxygen plasma treatment ensures the adhesion and thickness accuracy of the functional layer, thereby realizing the high stability of the device structure. The synergistic effect of the components in material selection, transmission performance and thickness control optimizes the photoelectric conversion efficiency, improves the application prospect of the panel in the fields of intelligent lighting, energy-saving display, etc., while reducing the preparation complexity and cost, and has important industry promoting effect and irreplaceability. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0053] Figure 1 The structure diagram of the organic white light illumination panel with adjustable color temperature of the present application;

[0054] Figure 2 The electroluminescence spectrum of the organic white light illumination panel with adjustable color temperature in embodiment 1 of the present application under alternating voltage change;

[0055] Figure 3 The CIE 1931 color coordinates of the organic white light illumination panel with adjustable color temperature in embodiment 1 of the present application under different voltages;

[0056] Figure 4 The current density-voltage-brightness curve of the organic white light illumination panel with adjustable color temperature in embodiment 1 of the present application;

[0057] Figure 5 The preparation flowchart of embodiment 1 of the present application;

[0058] Figure 6 The mask plate of the upright subunit and the inverted subunit in embodiment 1 of the present application;

[0059] Figure 7 The photo of the working under different voltages in embodiment 2 of the present application;

[0060] In the figure: substrate 1, first electrode layer 2, second electrode layer 13, first electrode layer 2, second electrode layer 13, first hole injection layer 3, first hole transport layer 4, first light-emitting layer 7, second light-emitting layer 8, first electron transport layer 9, first electron injection layer 10, second electron injection layer 5, second electron transport layer 6, second hole transport layer 11, second hole injection layer 12, and AC power supply 14. DETAILED DESCRIPTION

[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention. Example

[0062] like Figure 1 As shown, an organic white light lighting panel with adjustable color temperature, the organic white light lighting panel includes, from bottom to top, a substrate 1, a first electrode layer 2, and a second electrode layer 13; between the first electrode layer 2 and the second electrode layer 13 are a plurality of upright sub-units and a plurality of inverted sub-units; the upright sub-units are, from bottom to top, a first hole injection layer 3, a first hole transport layer 4, a first light-emitting layer 7, a second light-emitting layer 8, a first electron transport layer 9, and a first electron injection layer 10; the inverted sub-units are, from bottom to top, a second electron injection layer 5, a second electron transport layer 6, a first light-emitting layer 7, a second electron injection layer 10, a second hole transport layer 4, a first light-emitting layer 7, a second electron transport layer 8, a first electron transport layer 9, and a first electron injection layer 10. A light-emitting layer 8, a second hole transport layer 11, and a second hole injection layer 12; the upright subunit and the inverted subunit jointly include a first light-emitting layer 7 and a second light-emitting layer 8; the first hole injection layer 3 and the second electron injection layer 5 are structurally separated from each other; the first hole transport layer 4 and the second electron transport layer 6 are structurally separated from each other; the first electron transport layer 9 and the second hole transport layer 11 are structurally separated from each other; the first electron injection layer 10 and the second hole injection layer 12 are structurally separated from each other; the first electrode layer 2 and the second electrode layer 13 are connected together through an AC power supply 14.

[0063] The substrate 1 of this embodiment is glass; the transmittance of the substrate 1 in the visible light range is 40%.

[0064] The planar dimensions of the upright sub-unit and the inverted sub-unit of this embodiment are 300 μm×300 μm, and the cell gap is 100 μm.

[0065] The first light-emitting layer 7 and the second light-emitting layer 8 of the embodiment are yellow light-emitting layer and blue light-emitting layer respectively; the yellow light-emitting layer and the blue light-emitting layer are composed of host material and guest material; the host material of the yellow light-emitting layer is 4,4'-bis(9-carbazolyl)biphenyl (CBP); the guest material of the yellow light-emitting layer is bis(4-phenyl-thieno[3,2-c]pyridin-C2,N) iridium(III) acetylacetonate (PO-01); the host material of the blue light-emitting layer is 4,4',4'-tris(carbazol-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridin-N,C2) picolyl iridium (FIrPic); the doping mass ratio between the host material and the guest material is 10:1.

[0066] The second electron injection layer 5 of the embodiment is 4,7-diphenyl-1,10-phenanthroline (Bphen) doped with magnesium, and the mass ratio of 4,7-diphenyl-1,10-phenanthroline to magnesium is 20:1. The first electrode layer 2 is an indium tin oxide electrode, and the transmittance of the indium tin oxide electrode in the visible light range is 60%.

[0067] The thickness of the first electrode layer 2 of the embodiment is 120 nm; the first hole transport layer 4 and the second hole transport layer 11 are equal-thickness transport layers, and the thickness is 20 nm; the first electron transport layer 9 and the second electron transport layer 6 are equal-thickness transport layers, and the thickness is 20 nm; the first light-emitting layer 7 and the second light-emitting layer 8 are equal-thickness light-emitting layers, and the thickness is 20 nm; the first electron injection layer 10 and the second electron injection layer 5 are equal-thickness injection layers, and the thickness is 30 nm; the second electrode layer 13 is aluminum, and the thickness is 120 nm.

[0068] The first hole injection layer 3 and the second hole injection layer 12 of the embodiment are 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)benzenamine] (TAPC); the first hole transport layer 4 is 4,4',4'-tris(carbazol-9-yl)triphenylamine (TCTA); the second electron transport layer 6 is 4,7-diphenyl-1,10-phenanthroline (Bphen); the first electron transport layer 9 and the first electron injection layer 10 are 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB).

[0069] The preparation method of the color temperature adjustable organic white light illumination panel of the embodiment comprises the following steps:

[0070] Step S1: clean the surface of the first electrode layer 2 on the substrate 1 by Decon 90 alkaline cleaning solution, and use deionized water to ultrasonic clean three times, each time for 5 min; after cleaning, remove the water on the surface of the substrate by nitrogen, and heat to dry, the drying temperature is 100°C, the drying time is 10 min, and after drying, use oxygen plasma to treat for 5 min;

[0071] Step S2: place the substrate 1 and the first electrode layer 2 after step 1 into a multi-source organic molecule vapor deposition system, and vacuumize to 6×10 -4 Pa, evaporate the first hole injection layer 3 and the first hole transport layer 4 on the first electrode layer 2 by the upright sub-unit precision metal mask plate;

[0072] Step S3: replace the inverted sub-unit precision metal mask plate, and evaporate the second electron injection layer 5 and the second electron transport layer 6 on the first electrode layer 2 in turn;

[0073] Step S4: replace the large-area mask plate, and evaporate the first light-emitting layer 7 and the second light-emitting layer 8 on the first hole transport layer 4 and the second electron transport layer 6 in turn;

[0074] Step S5: replace the upright sub-unit precision metal mask plate, and evaporate the first electron transport layer 9 and the first electron injection layer 10 on the second light-emitting layer 8 in turn;

[0075] Step S6: replace the inverted sub-unit precision metal mask plate, and evaporate the second hole transport layer 11 and the second hole injection layer 12 on the second light-emitting layer 8 in turn;

[0076] Step S7: replace the metal electrode mask plate, and evaporate the second metal electrode 13 on the first electron injection layer 10 and the second hole injection layer 12.

[0077] The thickness and growth rate of the thin film grown by the vacuum thermal evaporation process in Example 1 are controlled by an L-400 film thickness controller produced in the United States, and the performance of the prepared device is tested at room temperature in air by using a photoelectric test system based on a Keithley 2400 current-voltage source and an Otsuka Electronics MCPD-9800 spectrometer.

[0078] The test results in this embodiment show that the electroluminescence spectrum of the color temperature adjustable OLED under alternating voltage change is as shown in FIG. 4. Figure 2 As can be seen, under a 9V bias, the blue light intensity remains unchanged, and the intensity at the yellow light peak of 562 nm becomes stronger as the negative bias amplitude becomes larger, and for the same reason, under a -9V bias, the yellow light intensity remains unchanged, and the blue light peak at 470 nm becomes stronger as the positive bias amplitude becomes larger, so by controlling the alternating input amplitude, the conversion of multiple color temperatures is realized.

[0079] The CIE1931 color coordinates of the color temperature adjustable OLED under different alternating voltages are as shown in FIG. 5.Figure 3 As shown, the device can change from high color temperature to low color temperature.

[0080] The current density-voltage-brightness curve of the color temperature adjustable OLED is shown in Figure 4 As shown, the positive and negative turn-on voltages are 3.25 V and 3.75 V respectively, and the brightness increases with the increase of voltage.

[0081] The device preparation flow chart is shown in Figure 5 As shown, the final effect diagram is shown in Figure 6 As shown, the device shows high color temperature under positive bias (9 V, 0 V), and changes from high color temperature to low color temperature by continuously increasing the amplitude of negative bias. Figure 7 Embodiment

[0082] As shown in Figure 1 A color temperature adjustable organic white light illumination panel, the organic white light illumination panel comprises from bottom to top a substrate 1, a first electrode layer 2, a second electrode layer 13; between the first electrode layer 2 and the second electrode layer 13 are a plurality of normal sub-units and a plurality of inverted sub-units; the normal sub-unit comprises from bottom to top a first hole injection layer 3, a first hole transport layer 4, a first light emitting layer 7, a second light emitting layer 8, a first electron transport layer 9, and a first electron injection layer 10; the inverted sub-unit comprises from bottom to top a second electron injection layer 5, a second electron transport layer 6, a first light emitting layer 7, a second light emitting layer 8, a second hole transport layer 11, and a second hole injection layer 12; the normal sub-unit and the inverted sub-unit jointly comprise the first light emitting layer 7 and the second light emitting layer 8; the first hole injection layer 3 and the second electron injection layer 5 are separated from each other in structure; the first hole transport layer 4 and the second electron transport layer 6 are separated from each other in structure; the first electron transport layer 9 and the second hole transport layer 11 are separated from each other in structure; the first electron injection layer 10 and the second hole injection layer 12 are separated from each other in structure; the first electrode layer 2 and the second electrode layer 13 are connected together by an alternating current power supply 14.

[0083] The substrate 1 of the embodiment is polyimide; the transmittance of the substrate 1 in the visible light range is 30%.

[0084] ​The planar size of the upright sub-unit and the inverted sub-unit of the embodiment is 510 μm x 510 μm, and the unit gap is 220 μm. The first light-emitting layer 7 and the second light-emitting layer 8 are a yellow light-emitting layer and a blue light-emitting layer respectively; the yellow light-emitting layer and the blue light-emitting layer are composed of a host material and a guest material; the host material of the yellow light-emitting layer is 4,4'-bis(9-carbazolyl)biphenyl (CBP); the guest material of the yellow light-emitting layer is bis(4-phenyl-thieno[3,2-c]pyridin-C2,N) iridium(III) acetylacetonate (PO-01); the host material of the blue light-emitting layer is 4,4',4'-tris(3-methylphenylphenylamino)triphenylamine (MTDATA); and the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridin-N,C2) picolyl iridium (FIrPic); the doping mass ratio between the host material and the guest material is 14:1.

[0085] The second electron injection layer 5 of the embodiment is 4,7-diphenyl-1,10-phenanthroline (Bphen) doped with magnesium, and the mass ratio of 4,7-diphenyl-1,10-phenanthroline to magnesium is 16:1. The first electrode layer 2 is an indium tin oxide electrode, and the transmittance of the electrode in the visible light range is 60%.

[0086] The thickness of the first electrode layer 2 of the embodiment is 136 nm; the first hole transport layer 4 and the second hole transport layer 11 are equal-thickness transport layers, and the thickness is 44 nm; the first electron transport layer 9 and the second electron transport layer 6 are equal-thickness transport layers, and the thickness is 50 nm; the first light-emitting layer 7 and the second light-emitting layer 8 are equal-thickness light-emitting layers, and the thickness is 60 nm; the first electron injection layer 10 and the second electron injection layer 5 are equal-thickness injection layers, and the thickness is 15 nm; and the second electrode layer 13 is aluminum, and the thickness is 100 nm.

[0087] The first hole injection layer 3 and the second hole injection layer 12 of the embodiment are 4,4'-cyclohexyl-N,N-bis(4-methylphenyl)benzylamine; the first hole transport layer 4 is 4,4',4'-tris(3-methylphenylphenylamino)triphenylamine (TCTA); the second electron transport layer 6 is 4,7-diphenyl-1,10-phenanthroline (Bphen); the first electron transport layer 9 and the first electron injection layer 10 are 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB).

[0088] The preparation method of the color temperature adjustable organic white light illumination panel of the embodiment comprises the following steps:

[0089] Step S1: clean the surface of the first electrode layer 2 on the substrate 1 by Decon 90 alkaline cleaning solution, and use deionized water to ultrasonic clean three times, each time for 14 min; after cleaning, remove the water on the surface of the substrate by nitrogen, and heat to dry, the drying temperature is 130℃, the drying time is 28 min, and after drying, use oxygen plasma to treat for 10 min;

[0090] Step S2: place the substrate 1 and the first electrode layer 2 treated in step 1 into a multi-source organic molecular vapor deposition system, and vacuumize to 6×10⁻ 4 Pa, evaporate the first hole injection layer 3 and the first hole transport layer 4 on the first electrode layer 2 by the upright sub-unit precision metal mask plate;

[0091] Step S3: replace the inverted sub-unit precision metal mask plate, and evaporate the second electron injection layer 5 and the second electron transport layer 6 on the first electrode layer 2 in turn;

[0092] Step S4: replace the large-area mask plate, and evaporate the first light-emitting layer 7 and the second light-emitting layer 8 on the first hole transport layer 4 and the second electron transport layer 6 in turn;

[0093] Step S5: replace the upright sub-unit precision metal mask plate, and evaporate the first electron transport layer 9 and the first electron injection layer 10 on the second light-emitting layer 8 in turn;

[0094] Step S6: replace the inverted sub-unit precision metal mask plate, and evaporate the second hole transport layer 11 and the second hole injection layer 12 on the second light-emitting layer 8 in turn;

[0095] Step S7: replace the metal electrode mask plate, and evaporate the second metal electrode 13 on the first electron injection layer 10 and the second hole injection layer 12. Embodiment

[0096] As Figure 1As shown in the figure, a color temperature adjustable organic white light illumination panel includes a substrate 1, a first electrode layer 2, and a second electrode layer 13 from bottom to top; a plurality of normal sub-units and a plurality of inverted sub-units are arranged between the first electrode layer 2 and the second electrode layer 13; the normal sub-unit includes, from bottom to top, a first hole injection layer 3, a first hole transport layer 4, a first light emitting layer 7, a second light emitting layer 8, a first electron transport layer 9, and a first electron injection layer 10; the inverted sub-unit includes, from bottom to top, a second electron injection layer 5, a second electron transport layer 6, the first light emitting layer 7, the second light emitting layer 8, a second hole transport layer 11, and a second hole injection layer 12; the normal sub-unit and the inverted sub-unit jointly include the first light emitting layer 7 and the second light emitting layer 8; the first hole injection layer 3 and the second electron injection layer 5 are separated from each other in structure; the first hole transport layer 4 and the second electron transport layer 6 are separated from each other in structure; the first electron transport layer 9 and the second hole transport layer 11 are separated from each other in structure; the first electron injection layer 10 and the second hole injection layer 12 are separated from each other in structure; and the first electrode layer 2 and the second electrode layer 13 are connected together by an alternating current power supply 14.

[0097] The substrate 1 of the embodiment is polyethylene naphthalate; the transmittance of the substrate 1 in the visible light range is 60%.

[0098] The planar size of the normal sub-unit and the inverted sub-unit of the embodiment is 1000 μm x 1000 μm, and the unit gap is 500 μm. The first light emitting layer 7 and the second light emitting layer 8 are a yellow light emitting layer and a blue light emitting layer respectively; the yellow light emitting layer and the blue light emitting layer are composed of a host material and a guest material; the host material of the yellow light emitting layer is 4,4'-bis(9-carbazolyl)biphenyl (CBP); the guest material of the yellow light emitting layer is bis(4-phenyl-thieno[3,2-c]pyridin-C2,N) iridium(III) acetylacetonate (PO-01); the host material of the blue light emitting layer is 4,4',4'-tris(carbazol-9-yl)-triphenylamine (TCTA); the guest material of the blue light emitting layer is bis(4,6-difluorophenylpyridin-N,C2) picolinato iridium (FIrPic); and the doping mass ratio between the host material and the guest material is 20:1.

[0099] The second electron injection layer 5 of the embodiment is 4,7-diphenyl-1,10-phenanthroline (Bphen) doped with magnesium, and the mass ratio of 4,7-diphenyl-1,10-phenanthroline to magnesium is 50:1. The first electrode layer 2 is an indium tin oxide electrode, and the transmittance of the first electrode layer 2 in the visible light range is 65%.

[0100] The thickness of the first electrode layer 2 of the embodiment is 500 nm; the first hole transport layer 4 and the second hole transport layer 11 are equal-thickness transport layers, with a thickness of 100 nm; the first electron transport layer 9 and the second electron transport layer 6 are equal-thickness transport layers, with a thickness of 100 nm; the first light-emitting layer 7 and the second light-emitting layer 8 are equal-thickness light-emitting layers, with a thickness of 100 nm; the first electron injection layer 10 and the second electron injection layer 5 are equal-thickness injection layers, with a thickness of 30 nm; and the second electrode layer 13 is metal silver, with a thickness of 200 nm.

[0101] The first hole injection layer 3 and the second hole injection layer 12 of the embodiment are 4,4'-cyclohexyl di-N,N-di(4-methylphenyl) aniline; the first hole transport layer 4 is 4,4',4'-tris(carbazol-9-yl) triphenylamine (TCTA); the second electron transport layer 6 is 4,7-diphenyl-1,10-phenanthroline (Bphen); the first electron transport layer 9 and the first electron injection layer 10 are 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB).

[0102] The preparation method of the color temperature-adjustable organic white light illumination panel of the embodiment includes the following steps:

[0103] Step S1: The surface of the first electrode layer 2 located on the substrate 1 is cleaned by a Decon 90 alkaline cleaning solution, and deionized water is used for ultrasonic cleaning three times, each time for 30 min; after cleaning, the water on the surface of the substrate is removed by nitrogen, and heating and drying are performed, with a drying temperature of 200°C and a drying time of 60 min; after drying, oxygen plasma treatment is performed for 20 min;

[0104] Step S2: The substrate 1 and the first electrode layer 2 treated in step 1 are placed in a multi-source organic molecular vapor deposition system, and vacuum pumping is performed to 6×10⁻ 4 Pa, the first hole injection layer 3 and the first hole transport layer 4 are evaporated on the first electrode layer 2 by using a positive sub-unit precision metal mask;

[0105] Step S3: The inverted sub-unit precision metal mask is replaced, and the second electron injection layer 5 and the second electron transport layer 6 are sequentially evaporated on the first electrode layer 2;

[0106] Step S4: The large-area mask is replaced, and the first light-emitting layer 7 and the second light-emitting layer 8 are sequentially evaporated on the first hole transport layer 4 and the second electron transport layer 6;

[0107] Step S5: The positive sub-unit precision metal mask is replaced, and the first electron transport layer 9 and the first electron injection layer 10 are sequentially evaporated on the second light-emitting layer 8;

[0108] Step S6: replace the inverted sub-unit precision metal mask, and evaporate the second hole transport layer 11 and the second hole injection layer 12 on the second light-emitting layer 8 in sequence;

[0109] Step S7: replace the metal electrode mask, and evaporate the second metal electrode 13 on the first electron injection layer 10 and the second hole injection layer 12.

[0110] Comparative Example 1

[0111] The difference between Example 1 and Comparative Example 1 is that the doping mass ratio of the host material (CBP) to the guest material (PO-01) of the yellow light-emitting layer is 1:1.

[0112] In Comparative Example 1, the doping mass ratio of the host material (CBP) to the guest material (PO-01) of the yellow light-emitting layer is 1:1, which is significantly different from the 10:1 of Example 1. The significant change in the doping ratio leads to a decrease in the energy transfer efficiency in the light-emitting layer, a decrease in the yellow light-emitting efficiency, and an inability to significantly enhance the intensity of the yellow light wave peak (562 nm) under negative bias voltage. In addition, due to the low yellow light-emitting efficiency, the color temperature adjustment range of the device under various alternating current bias conditions is narrowed, the change amplitude of the CIE1931 color coordinates is significantly reduced, and the overall color rendering and brightness of the device are not as good as those of Example 1.

[0113] Comparative Example 2

[0114] The difference between Example 1 and Comparative Example 2 is that the doping mass ratio of the host material (TCTA) to the guest material (FIrPic) of the blue light-emitting layer is 1:5.

[0115] In Comparative Example 2, the doping mass ratio of the host material (TCTA) to the guest material (FIrPic) of the blue light-emitting layer is 1:5, which is significantly different from the 10:1 of Example 1. The excessively high proportion of the guest material leads to an increase in the exciton quenching effect of the blue light, an inability to significantly increase the intensity of the blue light wave peak (470 nm) under positive bias voltage, and a decrease in the blue light-emitting efficiency. This decrease in blue light-emitting efficiency directly affects the color temperature adjustment range, making it impossible for the device to achieve a high color temperature state under positive bias voltage, and the overall brightness is significantly lower than that of Example 1.

[0116] Comparative Example 3

[0117] The difference between Example 1 and Comparative Example 3 is that the mass ratio of magnesium to Bphen in the second electron injection layer magnesium-doped Bphen is 1:60.

[0118] In Comparative Example 3, the mass ratio of magnesium to Bphen in the second electron injection layer is 1:60, which is much lower than 20:1 in Example 1. The lower magnesium doping concentration significantly reduces the electron injection capability of the electron injection layer, resulting in a significant decrease in the current density of the device. The test results show that the positive and negative turn-on voltages of the device increase to 4.5 V and 5.0 V, respectively, the slope of the luminance-voltage curve becomes smaller, and the rate of luminance increase with voltage decreases. In addition, due to the insufficient electron injection, the exciton recombination efficiency in the light-emitting layer is reduced, affecting the luminous intensity of yellow and blue light, and the color temperature adjustment performance of the device under alternating current driving is significantly inferior to that of Example 1.

[0119] Comparative Example 4

[0120] The first electron injection layer (10) and the second electron injection layer (5) are 50 nm thick, which is substantially the same as Example 1.

[0121] In Comparative Example 4, the thickness of the first electron injection layer (10) and the second electron injection layer (5) is increased from 30 nm in Example 1 to 50 nm. The over-thick electron injection layer increases the resistance of the device, affecting the charge injection efficiency, resulting in an increase in the positive and negative turn-on voltages of the device to 4.0 V and 4.5 V, respectively. In addition, the recombination efficiency of electrons and holes in the light-emitting layer decreases, and the luminous intensity of blue and yellow light under alternating bias conditions is weakened, and the maximum brightness of the device is reduced by about 30% compared with Example 1. At the same time, the color temperature adjustment range is narrowed, the change amplitude of CIE1931 color coordinates is reduced, and good color temperature conversion effect cannot be achieved.

[0122] The scheme of the present application realizes efficient charge injection and transport by precisely designing the structure of the normal subunit and the inverted subunit, optimizing the doping ratio of the light-emitting layer, the material ratio of the electron injection and transport layer, and the thickness distribution of each functional layer, significantly improving the luminous efficiency, brightness and stability of the device. At the same time, with the help of alternating current power supply, the luminous intensity of blue and yellow light can be accurately adjusted, so as to realize wide range of color temperature adjustment effect. Compared with the design in the comparative examples, the scheme of the present application has obvious advantages in photoelectric performance, color temperature adjustable range and process feasibility, and provides innovative technical support for the development of high-efficiency and adjustable color temperature organic white light illumination panel.

[0123] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts of each embodiment can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0124] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Modifications of these embodiments will occur to persons of skill in the art, and, while certain modifications are discussed, it is desired to be protected in accordance with the spirit and scope of the application. Therefore, the application is not limited to the specific embodiments shown and described, but only by the scope of the appended claims, unless otherwise specified.

Claims

1. An organic white light lighting panel with adjustable color temperature, characterized in that: The organic white light lighting panel comprises, from bottom to top, a substrate (1), a first electrode layer (2), and a second electrode layer (13); Between the first electrode layer (2) and the second electrode layer (13) are a plurality of upright subunits and a plurality of inverted subunits; The positive subunit is composed of a first hole injection layer (3), a first hole transport layer (4), a first light-emitting layer (7), a second light-emitting layer (8), a first electron transport layer (9), and a first electron injection layer (10) from bottom to top. The inverted subunit comprises, from bottom to top, a second electron injection layer (5), a second electron transport layer (6), a first light-emitting layer (7), a second light-emitting layer (8), a second hole transport layer (11), and a second hole injection layer (12); The upright subunit and the inverted subunit jointly comprise a first light-emitting layer (7) and a second light-emitting layer (8); The first hole injection layer (3) and the second electron injection layer (5) are structurally separated from each other; The first hole transport layer (4) and the second electron transport layer (6) are structurally separated from each other; The first electron transport layer (9) and the second hole transport layer (11) are structurally separated from each other; The first electron injection layer (10) and the second hole injection layer (12) are structurally separated from each other; The first electrode layer (2) and the second electrode layer (13) are connected together via an AC power supply (14).

2. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The substrate (1) is glass or polymer; Said polymer is polyimide or polyethylene naphthalate; The substrate (1) has a transmittance greater than 20% in the visible light range.

3. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The plane size of the upright subunit and the inverted subunit is 300 μm×300 μm to 1000 μm×1000 μm, and the unit gap is 100 to 500 μm.

4. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The first luminescent layer (7) and the second luminescent layer (8) are respectively a yellow luminescent layer and a blue luminescent layer; The yellow luminescent layer and the blue luminescent layer are composed of a host material and a guest material; The host material of the yellow light-emitting layer is 4,4'-bis(9-carbazole)biphenyl (CBP); the guest material of the yellow light-emitting layer is bis(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) acetylacetonate (PO-01); The blue light-emitting layer is composed of a host material of 4,4',4'-tris(carbazol-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2) picolinyl iridium (FIrPic); The doping mass ratio between the host material and the guest material is (20~1):

1.

5. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The second electron injection layer (5) is 4,7-diphenyl-1,10-phenanthroline (Bphen) doped with magnesium, and the mass ratio of 4,7-diphenyl-1,10-phenanthroline to magnesium is (50-2):

1.

6. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The first electrode layer (2) is an indium tin oxide electrode, and its transmittance in the visible light range is greater than 50%.

7. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The thickness of the first electrode layer (2) is 10-500 nm; The first hole transport layer (4) and the second hole transport layer (11) are equal-thickness transport layers, with a thickness of 20 to 100 nm; The first electron transport layer (9) and the second electron transport layer (6) are equal-thickness transport layers, with a thickness of 20 to 100 nm; The first luminescent layer (7) and the second luminescent layer (8) are luminescent layers of equal thickness, with a thickness of 20 to 100 nm; The first electron injection layer (10) and the second electron injection layer (5) are injection layers of equal thickness, with a thickness of 5 to 30 nm; The second electrode layer (13) is made of metal aluminum or metal silver, and has a thickness of 10-200 nm.

8. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The first hole injection layer (3) and the second hole injection layer (12) are 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC); The first hole transport layer (4) is 4,4',4'-tris(carbazol-9-yl)triphenylamine (TCTA); the second electron transport layer (6) is 4,7-diphenyl-1,10-phenanthroline (Bphen); The first electron transport layer (9) and the first electron injection layer (10) are 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]dipyridine (TmPyPB).

9. The method for preparing a color temperature adjustable organic white light lighting panel according to any one of claims 1 to 8, wherein: The following steps are involved: Step S1: cleaning the surface of the first electrode layer (2) on the substrate (1) with a Decon 90 alkaline cleaning solution, and ultrasonically cleaning it three times with deionized water, each time for 5 to 30 minutes; after cleaning, removing moisture from the surface of the substrate with nitrogen, and heating and drying it at a drying temperature of 100 to 200° C. for a drying time of 10 to 60 minutes, and then treating it with oxygen plasma for 5 to 20 minutes after drying; Step S2: Place the substrate (1) and the first electrode layer (2) processed in step S1 into a multi-source organic molecular vapor deposition system and evacuate the system to a vacuum of 6×10 -4 Pa, evaporating a first hole injection layer (3) and a first hole transport layer (4) on the first electrode layer (2) through a positive sub-unit precision metal mask; Step S3: replacing the inverted subunit precision metal mask, and sequentially evaporating a second electron injection layer (5) and a second electron transport layer (6) on the first electrode layer (2); Step S4: replacing a large-area mask, and sequentially vapor-depositing a first light-emitting layer (7) and a second light-emitting layer (8) on the first hole transport layer (4) and the second electron transport layer (6); Step S5: replacing the upright subunit precision metal mask, and sequentially evaporating the first electron transport layer (9) and the first electron injection layer (10) on the second light-emitting layer (8); Step S6: replacing the inverted subunit precision metal mask, sequentially evaporating a second hole transport layer (11) and a second hole injection layer (12) on the second light-emitting layer (8); Step S7: replacing the metal electrode mask, and vapor-depositing the second metal electrode (13) on the first electron injection layer (10) and the second hole injection layer (12).

Images