Preparation method of organic white light illumination panel with adjustable color temperature

Abstract

The invention discloses an organic white light illumination panel with adjustable color temperature and a preparation method thereof, and belongs to the technical field of organic electroluminescence. Comprising a substrate, a first electrode layer, a second electrode layer and a plurality of upright subunits and inverted subunits located between the first electrode layer and the second electrode layer. Each of the upright subunits and the inverted subunits comprises a yellow light-emitting layer and a blue light-emitting layer which are respectively formed by doping a host material and a guest material. The functional layers of the upright subunit and the inverted subunit comprise a hole injection layer, a hole transport layer, an electron transport layer and an electron injection layer which are structurally separated from each other. The panel is driven by an alternating current power supply, and independent adjustment of brightness and color temperature is realized through combination of the upright subunits and the inverted subunits. The preparation method comprises the steps of cleaning, drying, vacuum evaporation and the like. The problem that color temperature and brightness in an existing OLED device are difficult to independently control is solved, and the OLED device is simple in structure, excellent in performance and suitable for the field of intelligent illumination.

Description

Technical Field

[0001] The invention relates to the technical field of organic electroluminescence, and more particularly to a method for preparing an organic white light lighting panel with adjustable color temperature. Background Art

[0002] Smart lighting systems have gained widespread attention due to their ability to adjust the ambient color temperature according to the user's preferences. A key feature of these systems is their ability to independently control the spectrum and intensity of light, making them indispensable for creating human-centric environments that will have a positive impact on people's physical and mental health. White organic light-emitting diodes (OLEDs) are emerging as promising candidates for next-generation lighting due to their excellent flexibility, lightweight nature, and low production costs. Their ability to emit light over a wide spectral range and precisely adjust the intensity meets the requirements of smart lighting, positioning them as a prime candidate for future applications.

[0003] However, there are currently three main approaches to organic white light-emitting devices with adjustable color temperature. The first is multiple light-emitting layers in OLEDs, which faces the challenge of independent control of spectrum and brightness. The second approach is to solve this problem by vertically stacking multiple OLEDs with a semi-transparent intermediate electrode, which requires additional control logic to optimize current distribution, making the driving circuit and control process complicated. The third approach 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 lighting panel that can independently adjust brightness and color temperature and has good device performance and a preparation method thereof is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides an organic white light lighting panel with adjustable color temperature and a preparation method thereof, which can independently adjust the color temperature and brightness only through AC driving.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: An organic white light lighting panel with adjustable color temperature, the organic white light lighting panel comprising, from bottom to top, a substrate, a first electrode layer, and a second electrode layer; Between the first electrode layer and the second electrode layer are a plurality of upright subunits and a plurality of inverted subunits; The positive subunit is composed of 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 from bottom to top; The inverted subunit is, 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; The upright subunit and the inverted subunit jointly comprise a first light-emitting layer and a second light-emitting layer; The first hole injection layer and the second electron injection layer are structurally separated from each other; The first hole transport layer and the second electron transport layer are structurally separated from each other; The first electron transport layer and the second hole transport layer are structurally separated from each other; The first electron injection layer and the second hole injection layer are structurally separated from each other; The first electrode layer and the second electrode layer are connected together through an alternating current power supply.

[0007] Further, the substrate is glass or a polymer; Further, the polymer is polyimide or polyethylene naphthalate; Furthermore, the transmittance of the substrate in the visible light range is greater than 20%.

[0008] The present invention adopts glass or polyimide, polyethylene naphthalate as the design of the substrate is mainly used to enhance the light transmittance and mechanical stability of the organic white light lighting panel. The components work synergistically to ensure that the transmittance of the substrate in the visible light range is greater than 20%, thereby providing a stable basic support for the color temperature adjustment and light efficiency output of the panel.

[0009] Furthermore, the plane size of the upright subunit and the inverted subunit is 300 μm×300 μm~1000 μm×1000 μm, and the unit gap is 100~500 μm.

[0010] Furthermore, the first light-emitting layer and the second light-emitting layer are respectively a yellow light-emitting layer and a blue light-emitting layer; Furthermore, the yellow light-emitting layer and the blue light-emitting layer are composed of a doped host material and a guest material; Furthermore, the host material of the yellow light-emitting layer is 4,4'-di(9-carbazole)biphenyl (CBP); the guest material of the yellow light-emitting layer is acetylacetonate di(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) (PO-01); Furthermore, the blue light-emitting layer is a host material of 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2) iridium pyridine carboxylate (FIrPic); Furthermore, the doping mass ratio between the host material and the guest material is (20~1):1.

[0011] The present invention adopts the design of upright subunits and inverted subunits mainly to enhance the color temperature adjustment performance of the organic white light lighting panel. The precise design of the plane size and gap of the upright subunits and the inverted subunits ensures the light emission uniformity and structural stability. The yellow light-emitting layer is synergistically formed by 4,4'-di(9-carbazole)biphenyl (CBP) and acetylacetonate di(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) (PO-01), and the blue light-emitting layer is synergistically formed by 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA) and bis(4,6-difluorophenylpyridine-N,C2)picolinyliridium (FIrPic). The two light-emitting layers achieve spectral balance and controllable adjustment of color temperature by optimizing the doping ratio of the host material and the guest material. The components cooperate with each other in structure, which further improves the light efficiency output and stability of the panel.

[0012] Furthermore, 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.

[0013] Furthermore, the first electrode layer is an indium tin oxide electrode, and its transmittance in the visible light range is greater than 50%.

[0014] Furthermore, the thickness of the first electrode layer is 10-500 nm; Furthermore, the first hole transport layer and the second hole transport layer are equal-thickness transport layers, with a thickness of 20 to 100 nm; Furthermore, the first electron transport layer and the second electron transport layer are equal-thickness transport layers, with a thickness of 20 to 100 nm; Furthermore, the first light-emitting layer and the second light-emitting layer are light-emitting layers of equal thickness, with a thickness of 20 to 100 nm; Furthermore, the first electron injection layer and the second electron injection layer are equal-thickness injection layers, with a thickness of 5 to 30 nm; Furthermore, the second electrode layer is made of metal aluminum or metal silver, and has a thickness of 10-200 nm.

[0015] The present invention adopts the optimized design of functional layers mainly to enhance the light output and structural stability of organic white light lighting panels. The second electron injection layer is formed by doping magnesium with 4,7-diphenyl-1,10-phenanthroline (Bphen), and the electron injection efficiency is improved by adjusting the mass ratio. The first electrode layer is an indium tin oxide electrode, which has high light transmittance and synergizes with the hole transport layer, electron transport layer and light-emitting layer designed with equal thickness of each functional layer, effectively balancing carrier transport and light output. The thickness optimization of the first electron injection layer and the second electron injection layer further improves the interface injection effect. The second electrode layer is composed of metal aluminum or metal silver to ensure conductivity and stability. The precise design of each component jointly improves the photoelectric conversion efficiency and service life of the panel.

[0016] Furthermore, the first hole injection layer and the second hole injection layer are 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline](TAPC); Furthermore, the first hole transport layer is 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA); the second electron transport layer is 4,7-diphenyl-1,10-phenanthroline (Bphen); 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]bipyridine (TmPyPB); The present invention adopts a multifunctional layer collaborative design mainly for enhancing the carrier injection and transport performance of an organic white light lighting panel. The first hole injection layer and the second hole injection layer are composed of 4,4'-cyclohexyldi-N,N-di(4-methylphenyl)aniline to provide efficient hole injection. The first hole transport layer is composed of 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA), which synergistically optimizes the balanced transmission of holes and electrons with the second electron transport layer 4,7-diphenyl-1,10-phenanthroline (Bphen). 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]bipyridine (TmPyPB) to improve the electron injection efficiency. Each component realizes efficient injection and uniform distribution of carriers in the device through precise material selection and interlayer matching, thereby significantly improving the luminescence performance and stability of the panel.

[0017] The present invention also provides a method for preparing an organic white light lighting panel with adjustable color temperature, comprising the following steps: Step S1: cleaning the surface of the first electrode layer on the substrate with Decon 90 alkaline cleaning solution, and ultrasonically cleaning with deionized water for three times, each time for 5 to 30 minutes; after cleaning, removing moisture from the surface of the substrate with nitrogen, and heating and drying, the drying temperature is 100 to 200° C., the drying time is 10 to 60 minutes, and after drying, oxygen plasma treatment is used for 5 to 20 minutes; Step S2: Place the substrate and the first electrode layer processed in step 1 into a multi-source organic molecular vapor deposition system and evacuate to 6×10 -4 Pa, evaporating a first hole injection layer and a first hole transport layer on the first electrode layer through a positive subunit precision metal mask; Step S3: replacing the upright subunit precision metal mask, and sequentially evaporating a second electron injection layer and a second electron transport layer on the first electrode layer; Step S4: replacing a large-area mask, and sequentially evaporating a first light-emitting layer and a second light-emitting layer on the first hole transport layer and the second electron transport layer; Step S5: replacing the upright subunit precision metal mask, and sequentially evaporating the first electron transport layer and the first electron injection layer on the second light-emitting layer; Step S6: Replace the inverted subunit precision metal mask, and sequentially evaporate the second hole transport layer and the second hole injection layer on the second light-emitting layer; Step S7: replacing the metal electrode mask, and evaporating a second metal electrode on the first electron injection layer and the second hole injection layer.

[0018] The present invention adopts a step-by-step evaporation preparation method design mainly for enhancing the structural precision and luminescence performance of organic white light lighting panels. Decon 90 alkaline cleaning solution and oxygen plasma treatment are used to ensure the surface cleanliness and activity of the substrate and the first electrode layer, providing reliable guarantee for the attachment of subsequent functional layers. The sequential evaporation of the upright functional layer, the inverted functional layer and the light-emitting functional layer realizes precise positioning and thickness control between layers through a precision 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 balance transmission performance. Finally, a stable device structure is formed by evaporating the second metal electrode. The step design ensures the efficient luminescence and stability of the panel. Beneficial Effects

[0019] 1. The present invention improves the light transmittance and mechanical stability of the organic white light lighting panel by using glass or polyimide, polyethylene naphthalate as a substrate, and significantly improves the accuracy of the panel color temperature adjustment and the stability of the light output compared with the prior art. The precise design of the upright subunit and the inverted subunit achieves luminous uniformity, and the yellow light-emitting layer and the blue light-emitting layer are optimized by the coordinated doping of the host material and the guest material to ensure the spectral balance and color temperature controllability. The optimized design of the functional layer, such as the high light transmittance of the Bphen-doped magnesium electron injection layer and the indium tin oxide electrode, works in synergy with the hole transport layer, electron transport layer and light-emitting layer of equal thickness design, which not only improves the carrier transfer efficiency, but also enhances the photoelectric conversion performance. The precise ratio and thickness control of each component ensure structural stability and long service life. The design effectively solves the pain point that the color temperature and brightness are difficult to adjust independently in the prior art, promotes the development of the field of intelligent lighting, and has broad application prospects and irreplaceable advantages.

[0020] 2. The present invention significantly improves the carrier injection efficiency, transmission balance and luminescence stability of the organic white light lighting panel through the coordinated design and precise preparation process of the multifunctional layer. Compared with the prior art, its innovation lies in the use of materials such as 4,4'-cyclohexyldi-N,N-di(4-methylphenyl)aniline and 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1''-terphenyl]-3,3''-diyl]bipyridine (TmPyPB), and optimizes hole and electron injection through precise ratio and interlayer matching, solving the problems of uneven carrier distribution and low luminescence 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 achieving a high stability of the device structure. The synergistic effect of each component in material selection, transmission performance and thickness control optimizes the photoelectric conversion efficiency, improves the application prospects of the panel in the fields of intelligent lighting, energy-saving display, etc., and reduces the preparation complexity and cost, which has an important industry driving role and irreplaceability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 This is a schematic diagram of the structure of an organic white light lighting panel with adjustable color temperature according to the present invention; Figure 2The electroluminescence spectrum of the color temperature adjustable organic white light lighting panel under the change of AC voltage in embodiment 1 of the present invention; Figure 3 are the CIE 1931 color coordinates of the color temperature adjustable organic white light lighting panel under different voltages in Example 1 of the present invention; Figure 4 is a current density-voltage-brightness curve of the color temperature adjustable organic white light lighting panel in Example 1 of the present invention; Figure 5 is a preparation flow chart of Example 1 of the present invention; Figure 6 The mask plates are the upright subunit and the inverted subunit of embodiment 1 of the present invention; Figure 7 These are photos of Example 2 of the present invention when working under different voltages; 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, AC power supply 14. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention. Example

[0024] like Figure 1As shown, an organic white light lighting panel with adjustable color temperature, 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 upright subunits 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 subunits 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, and a second hole transport layer 4. 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.

[0025] The substrate 1 of this embodiment is glass; the transmittance of the substrate 1 in the visible light range is 40%.

[0026] The plane size of the upright subunit and the inverted subunit of this embodiment is 300 μm×300 μm, and the cell gap is 100 μm.

[0027] In this embodiment, the first light-emitting layer 7 and the second light-emitting layer 8 are respectively a yellow light-emitting layer and a blue light-emitting layer; the yellow light-emitting layer and the blue light-emitting layer are doped with a host material and a guest material; the host material of the yellow light-emitting layer is 4,4'-di(9-carbazole)biphenyl (CBP); the guest material of the yellow light-emitting layer is acetylacetonate di(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) (PO-01); the host material of the blue light-emitting layer is 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2)pyridinecarboxylateiridium (FIrPic); the doping mass ratio between the host material and the guest material is 10:1.

[0028] The second electron injection layer 5 of this 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 its transmittance in the visible light range is 60%.

[0029] The thickness of the first electrode layer 2 of this embodiment is 120nm; the first hole transport layer 4 and the second hole transport layer 11 are transport layers of equal thickness with a thickness of 20nm; the first electron transport layer 9 and the second electron transport layer 6 are transport layers of equal thickness with a thickness of 20nm; the first light-emitting layer 7 and the second light-emitting layer 8 are light-emitting layers of equal thickness with a thickness of 20nm; the first electron injection layer 10 and the second electron injection layer 5 are injection layers of equal thickness with a thickness of 30nm; the second electrode layer 13 is metal aluminum with a thickness of 120nm.

[0030] In this embodiment, the first hole injection layer 3 and the second hole injection layer 12 are 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC); the first hole transport layer 4 is 4,4',4'-tri(carbazole-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]bipyridine (TmPyPB).

[0031] A method for preparing an organic white light lighting panel with adjustable color temperature in this embodiment includes the following steps: Step S1: cleaning the surface of the first electrode layer 2 on the substrate 1 with Decon 90 alkaline cleaning solution, and ultrasonically cleaning with deionized water for three times, each time for 5 minutes; after cleaning, removing moisture from the surface of the substrate with nitrogen, and heating and drying at a drying temperature of 100° C. for 10 minutes, and then using oxygen plasma treatment for 5 minutes after drying; Step S2: Place the substrate 1 and the first electrode layer 2 processed in step 1 into a multi-source organic molecular vapor deposition system and evacuate the system to a vacuum of 6×10 -4 Pa, evaporating the first hole injection layer 3 and the first hole transport layer 4 on the first electrode layer 2 through the upright sub-unit precision metal mask; Step S3: replacing the inverted subunit precision metal mask, and sequentially evaporating the second electron injection layer 5 and the second electron transport layer 6 on the first electrode layer 2; Step S4: replacing a large-area mask, and sequentially evaporating 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: Replace the inverted subunit precision metal mask, sequentially depositing the second hole transport layer 11 and the second hole injection layer 12 on the second light-emitting layer 8; Step S7 : replacing the metal electrode mask, and evaporating the second metal electrode 13 on the first electron injection layer 10 and the second hole injection layer 12 .

[0032] The thickness and growth rate of the thin film grown by the vacuum thermal evaporation process in Example 1 were controlled by an L-400 film thickness controller made in the United States, and the performance of the prepared device was tested under room temperature conditions in air using a photoelectric testing system based on a Keithley 2400 current and voltage source and an Otsuka Electronics MCPD-9800 spectrometer.

[0033] The test results of this embodiment show that the electroluminescence spectrum of the color temperature adjustable OLED under the alternating voltage is as follows: Figure 2 As shown, it can be seen that under the 9V bias, the blue light intensity remains unchanged while the intensity at the yellow light peak of 562nm increases with the negative bias amplitude and thus becomes stronger. Similarly, under the -9V bias, the yellow light intensity remains unchanged while the blue light peak of 470nm increases with the positive bias amplitude and thus becomes stronger. Therefore, the AC input amplitude is controlled to achieve the conversion of various color temperatures.

[0034] The CIE1931 color coordinates of color temperature adjustable OLED under different AC voltages are as follows Figure 3 As shown, the device can be changed from high color temperature to low color temperature.

[0035] The current density-voltage-brightness curve of color temperature adjustable OLED is as follows: Figure 4 As shown, its positive and negative turn-on voltages are 3.25 V and 3.75 V respectively, and the brightness increases with increasing voltage.

[0036] Device preparation flow chart Figure 5 As shown, the inverted subunit and the upright subunit mask are as follows Figure 6 The final effect is shown in the figure Figure 7 As shown in the figure, under positive bias, the device presents a high color temperature (9V, 0V, and by continuously increasing the negative bias amplitude, the device changes from high color temperature to low color temperature. Example

[0037] like Figure 1As shown, an organic white light lighting panel with adjustable color temperature, 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 upright subunits 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 subunits 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, and a second hole transport layer 4. 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.

[0038] The substrate 1 of this embodiment is polyimide; the transmittance of the substrate 1 in the visible light range is 30%.

[0039] The plane size of the upright subunit and the inverted subunit of this embodiment is 510μm×510μm, and the unit gap is 220μm. The first light-emitting layer 7 and the second light-emitting layer 8 are yellow light-emitting layer and blue light-emitting layer respectively; the yellow light-emitting layer and the blue light-emitting layer are doped with a host material and a guest material; the host material of the yellow light-emitting layer is 4,4'-di(9-carbazole)biphenyl (CBP); the guest material of the yellow light-emitting layer is acetylacetonate di(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) (PO-01); the host material of the blue light-emitting layer is 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2)pyridinecarboxylateiridium (FIrPic); the doping mass ratio between the host material and the guest material is 14:1.

[0040] The second electron injection layer 5 of this 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 its transmittance in the visible light range is 60%.

[0041] The thickness of the first electrode layer 2 of this embodiment is 136nm; the first hole transport layer 4 and the second hole transport layer 11 are equal thickness transport layers with a thickness of 44nm; the first electron transport layer 9 and the second electron transport layer 6 are equal thickness transport layers with a thickness of 50nm; the first light-emitting layer 7 and the second light-emitting layer 8 are equal thickness light-emitting layers with a thickness of 60nm; the first electron injection layer 10 and the second electron injection layer 5 are equal thickness injection layers with a thickness of 15nm; the second electrode layer 13 is metal aluminum with a thickness of 100nm.

[0042] The first hole injection layer 3 and the second hole injection layer 12 of this embodiment are 4,4'-cyclohexyldi-N,N-di(4-methylphenyl)aniline; the first hole transport layer 4 is 4,4',4'-tri(carbazole-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]bipyridine (TmPyPB).

[0043] A method for preparing an organic white light lighting panel with adjustable color temperature in this embodiment includes the following steps: Step S1: cleaning the surface of the first electrode layer 2 on the substrate 1 with Decon 90 alkaline cleaning solution, and ultrasonically cleaning with deionized water for three times, each time for 14 minutes; after cleaning, removing moisture from the surface of the substrate with nitrogen, and heating and drying, the drying temperature is 130° C., the drying time is 28 minutes, and after drying, oxygen plasma treatment is used for 10 minutes; Step S2: Place the substrate 1 and the first electrode layer 2 processed in step 1 into a multi-source organic molecular vapor deposition system and evacuate the system to a vacuum of 6×10⁻ 4 Pa, evaporating the first hole injection layer 3 and the first hole transport layer 4 on the first electrode layer 2 through the upright sub-unit precision metal mask; Step S3: replacing the inverted subunit precision metal mask, and sequentially evaporating the second electron injection layer 5 and the second electron transport layer 6 on the first electrode layer 2; Step S4: replacing a large-area mask, and sequentially evaporating 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, and sequentially evaporating the second hole transport layer 11 and the second hole injection layer 12 on the second light-emitting layer 8; Step S7 : replacing the metal electrode mask, and evaporating the second metal electrode 13 on the first electron injection layer 10 and the second hole injection layer 12 . Example

[0044] like Figure 1 As shown, an organic white light lighting panel with adjustable color temperature, 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 upright subunits 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 subunits 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, and a second hole transport layer 4. 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.

[0045] The substrate 1 of this embodiment is polyethylene naphthalate; the transmittance of the substrate 1 in the visible light range is 60%.

[0046] The plane size of the upright subunit and the inverted subunit of this embodiment is 1000μm×1000μm, and the unit gap is 500μm. The first light-emitting layer 7 and the second light-emitting layer 8 are yellow light-emitting layer and blue light-emitting layer respectively; the yellow light-emitting layer and the blue light-emitting layer are doped with a host material and a guest material; the host material of the yellow light-emitting layer is 4,4'-di(9-carbazole)biphenyl (CBP); the guest material of the yellow light-emitting layer is acetylacetonate di(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) (PO-01); the host material of the blue light-emitting layer is 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2)pyridinecarboxylateiridium (FIrPic); the doping mass ratio between the host material and the guest material is 20:1.

[0047] The second electron injection layer 5 of this 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 its transmittance in the visible light range is 65%.

[0048] The thickness of the first electrode layer 2 of this embodiment is 500nm; the first hole transport layer 4 and the second hole transport layer 11 are equal thickness transport layers with a thickness of 100nm; the first electron transport layer 9 and the second electron transport layer 6 are equal thickness transport layers with a thickness of 100nm; the first light-emitting layer 7 and the second light-emitting layer 8 are equal thickness light-emitting layers with a thickness of 100nm; the first electron injection layer 10 and the second electron injection layer 5 are equal thickness injection layers with a thickness of 30nm; the second electrode layer 13 is metallic silver with a thickness of 200nm.

[0049] The first hole injection layer 3 and the second hole injection layer 12 of this embodiment are 4,4'-cyclohexyldi-N,N-di(4-methylphenyl)aniline; the first hole transport layer 4 is 4,4',4'-tri(carbazole-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]bipyridine (TmPyPB).

[0050] A method for preparing an organic white light lighting panel with adjustable color temperature in this embodiment includes the following steps: Step S1: cleaning the surface of the first electrode layer 2 on the substrate 1 with Decon 90 alkaline cleaning solution, and ultrasonically cleaning with deionized water for three times, each time for 30 minutes; after cleaning, removing moisture from the surface of the substrate with nitrogen, and heating and drying at a drying temperature of 200° C. for 60 minutes, and then treating with oxygen plasma for 20 minutes after drying; Step S2: Place the substrate 1 and the first electrode layer 2 processed in step 1 into a multi-source organic molecular vapor deposition system and evacuate the system to a vacuum of 6×10⁻ 4 Pa, evaporating the first hole injection layer 3 and the first hole transport layer 4 on the first electrode layer 2 through the upright sub-unit precision metal mask; Step S3: replacing the inverted subunit precision metal mask, and sequentially evaporating the second electron injection layer 5 and the second electron transport layer 6 on the first electrode layer 2; Step S4: replacing a large-area mask, and sequentially evaporating 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, and sequentially evaporating the second hole transport layer 11 and the second hole injection layer 12 on the second light-emitting layer 8; Step S7 : replacing the metal electrode mask, and evaporating the second metal electrode 13 on the first electron injection layer 10 and the second hole injection layer 12 .

[0051] Comparative Example 1 The method is basically the same as Example 1, except 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.

[0052] 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. Compared with 10:1 in 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 luminous efficiency of yellow light, and a failure to significantly enhance the intensity of the yellow light peak (562nm) under negative bias. In addition, due to the low luminous efficiency of yellow light, the color temperature adjustment range of the device under various AC bias conditions becomes narrower, the change range of the CIE1931 color coordinates is significantly reduced, and the overall color rendering and brightness performance of the device are not as good as those of Example 1.

[0053] Comparative Example 2 The method is basically the same as Example 1, except that the doping mass ratio of the host material (TCTA) to the guest material (FIrPic) of the blue light-emitting layer is 1:5.

[0054] 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. Compared with 10:1 in Example 1, the excessively high guest material ratio leads to an enhanced exciton quenching effect of the blue light, and the intensity of the blue light peak (470nm) fails to increase significantly under positive bias, and the blue light luminescence efficiency decreases. This decrease in blue light luminescence efficiency directly affects the range of color temperature adjustment, making it impossible for the device to achieve a high color temperature state under positive bias, and the overall brightness is significantly lower than that of Example 1.

[0055] Comparative Example 3 It is basically the same as Example 1, except that the mass ratio of magnesium to Bphen in the magnesium-doped Bphen in the second electron injection layer is 1:60.

[0056] 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 capacity 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 4.5V and 5.0V, respectively, the slope of the brightness-voltage curve decreases, and the rate at which the brightness increases with the voltage decreases. In addition, due to the lack of electron injection, the exciton recombination efficiency in the light-emitting layer is reduced, which affects the luminous intensity of yellow light and blue light, and the color temperature adjustment performance of the device under AC drive is significantly inferior to that of Example 1.

[0057] Comparative Example 4 It is basically the same as Example 1, except that the thickness of the first electron injection layer (10) and the second electron injection layer (5) is 50 nm.

[0058] 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. Too thick electron injection layers increase the resistance of the device, affecting the charge injection efficiency, resulting in the positive and negative turn-on voltages of the device being increased 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 light and yellow light is weakened under AC bias conditions, 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, and the variation range of the CIE1931 color coordinates is reduced, and a good color temperature conversion effect cannot be achieved.

[0059] The solution of the present invention achieves efficient charge injection and transmission by accurately designing the structure of the upright subunit and the inverted subunit, optimizing the doping ratio of the light-emitting layer, the material ratio of the electron injection and transport layers, and the thickness distribution of each functional layer, and significantly improves the luminous efficiency, brightness and stability of the device. At the same time, with the help of AC power drive, the luminous intensity of blue light and yellow light can be accurately adjusted, thereby achieving a wide range of color temperature adjustment effects. Compared with the design in the comparative example, the solution of the present invention shows obvious advantages in terms of optoelectronic performance, adjustable color temperature range and process feasibility, and provides innovative technical support for the development of efficient, color temperature adjustable organic white light lighting panels.

[0060] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0061] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic white light lighting panel with adjustable color temperature, characterized in that: The organic white light illumination 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 sub-units and a plurality of inverted sub-units; The positive subunits 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 subunits 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 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 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 via an alternating current power source (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; The 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~1000 μm×1000 μm, and the unit gap is 100~500 μm.

4. The color temperature adjustable organic white light lighting panel according to claim 1, characterized in that: The first light-emitting layer (7) and the second light-emitting layer (8) are respectively a yellow light-emitting layer and a blue light-emitting layer; The yellow light-emitting layer and the blue light-emitting layer are formed by doping a host material and a guest material; The host material of the yellow light-emitting layer is 4,4'-di(9-carbazole)biphenyl (CBP); the guest material of the yellow light-emitting layer is acetylacetonate di(4-phenyl-thiophene[3,2-c]pyridine-C2,N)iridium(III) (PO-01); The blue light-emitting layer is a main material of 4,4',4'-tri(carbazole-9-yl)triphenylamine (TCTA); the guest material of the blue light-emitting layer is bis(4,6-difluorophenylpyridine-N,C2) iridium pyridine (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 20-100 nm; The first electron transport layer (9) and the second electron transport layer (6) are transport layers of equal thickness, with a thickness of 20 to 100 nm; The first light-emitting layer (7) and the second light-emitting layer (8) are light-emitting 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'-tri(carbazole-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]bipyridine (TmPyPB).

9. The method for preparing a color temperature adjustable organic white light lighting panel according to any one of claims 1 to 8, characterized in that: 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 with deionized water for three times, each time for 5 to 30 minutes; after cleaning, removing moisture from the surface of the substrate with nitrogen, and heating and drying, the drying temperature is 100 to 200° C., the drying time is 10 to 60 minutes, and after drying, oxygen plasma treatment is used for 5 to 20 minutes; Step S2: Place the substrate (1) and the first electrode layer (2) processed in step 1 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, and 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).

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