High-efficiency and long-service-life dimmable organic light-emitting device and use thereof

Abstract

The present invention relates to a high-efficiency and long-service-life dimmable organic light-emitting device and a use thereof. The light-emitting device comprises: a light-emitting layer. In the light-emitting layer, two or more host materials are mixed together and a luminescent material is doped in the layer; the luminescent material is a platinum complex, and the luminescent material emits light in a monomer emission state and at least one aggregation emission state; the LUMO energy level of at least one host material is lower than the LUMO energy level of the luminescent material or the difference between the LUMO energy level of at least one host material and the LUMO energy level of the luminescent material is less than 0.2 eV, or the host material in the light-emitting layer employs a combination of SF-BCZ and SF-TRZ. The light-emitting layer or the light-emitting device can be applied to fixed visual display units, mobile visual display units, lighting units, keyboards, clothing, decorative items, clothing accessories, wearable devices, medical monitoring devices, wallpapers, tablet computers, laptops, advertising panels, panel display units, household appliances, and office supplies.

Description

[Amended according to Rule 26 on 25.12.2025] A high-efficiency, long-life tunable light organic light-emitting device and its application [Amended according to Rule 26 on 25.12.2025] TECHNICAL FIELD

[0001] [Amended according to Rule 26 on 25.12.2025] The present application relates to the technical field of OLED lighting, in particular to a high-efficiency, long-life tunable light organic light-emitting device and its application. [Amended according to Rule 26 on 25.12.2025] BACKGROUND

[0002] [Amended according to Rule 26 on 25.12.2025] For color-tunable OLEDs (color-tunable OLEDs, CT-OLEDs), there are many disadvantages in the color-tunable scheme using two or more emitters or three or more light-emitting layers or two or more sub-OLEDs, and the problems of "color aging" and the like caused by different lifetimes of different emitters can be avoided by simplifying the device structure so that only a single emitter is needed.

[0003] [Amended according to Rule 26 on 25.12.2025] The prior art discloses many technologies for realizing color-tunable OLEDs, for example, CN102280592A discloses an organic electroluminescent device for realizing color-tunable light emission based on a single light-emitting material; CN116602071A discloses a color-tunable OLED with long service life; CN110945669A discloses a color-tunable organic light-emitting diode device based on a single emitter and a method thereof.

[0004] [Amended according to Rule 26 on 25.12.2025] However, the color-tunable OLED devices (or light-emitting devices) of the prior art have many defects such as low efficiency, poor stability, small tunable light range, etc., which need to be solved. For example, the device with Pt-X-4 used in CN116602071A has an LT 90@100nits estimated to be 19105 hours, and the lifetime is short, and the thermal stability of the emitter Pt-X-4 (T d = 430℃) used is low, which is difficult to meet the requirements of practical application. [Amended according to Rule 26 on 25.12.2025] SUMMARY

[0005] [Amended according to Rule 26 on 25.12.2025] In view of the deficiencies of the prior art, the present application provides a high-efficiency, long-life tunable light organic light-emitting device and its application to solve at least part of the above technical problems.

[0006] [Rule 26 correction 25.12.2025] The present invention discloses a high efficiency, long lifetime, tunable light organic light emitting device, comprising: an anode and a cathode configured to have a driving voltage on both electrodes; and a plurality of organic layers between the two electrodes, wherein at least one of the organic layers is a light emitting layer, in which two or more host materials are mixed together and one light emitting material is doped in the layer; the light emitting material is a platinum complex, and it has a monomer emission state and at least one aggregate emission state; there is at least one host material containing a triazine group, and the LUMO energy level of the host material is lower than that of the light emitting material or the difference between the LUMO energy levels of the two is less than 0.2 eV.

[0007] [Rule 26 correction 25.12.2025] According to a preferred embodiment, the light emitting material in the light emitting layer is selected to be an efficient phosphorescent Pt(II) emitter coordinated by a tetradentate [O^N^C^N] ligand, wherein the emitter is represented by the following chemical formula:

[0008] [Rule 26 correction 25.12.2025] In the chemical formula,

[0009] [Rule 26 correction 25.12.2025] X is independently a 5 or 6 membered heterocycle,

[0010] [Rule 26 correction 25.12.2025] R1-R3 are independently selected from the group consisting of hydrogen, halogen, hydroxyl, unsubstituted alkyl, substituted alkyl, cycloalkyl, unsubstituted aryl, substituted aryl, acyl, alkoxy, acyloxy, amino, nitro, acylamino, aralkyl, cyano, carboxyl, thiol, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl, or alkoxycarbonyl groups,

[0011] [Rule 26 correction 25.12.2025] R4 is independently selected from the group consisting of hydrogen, halogen, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, sulfonyl, phosphine, and combinations thereof,

[0012] [Rule 26 correction 25.12.2025] Each pair of adjacent R groups in R1-R3 is independently one or two independent groups or atoms or selected to form a 5-6 membered ring,

[0013] [Rule 26 correction 25.12.2025] R1-R3 represent mono-, di-, tri-, tetra-substitution or no substitution.

[0014] [Rule 26 correction 25.12.2025] According to a preferred embodiment, R4is independently selected from the group consisting of dibenzofuranyl or dibenzothiophenyl.

[0015] [Rule 26 correction 25.12.2025] According to a preferred embodiment, the light-emitting material in the light-emitting layer is selected to be tetra-Pt-dbf or tetra-Pt-dbt, wherein tetra-Pt-dbf and tetra-Pt-dbt are represented by the following chemical formulas, respectively:

[0016] [Rule 26 correction 25.12.2025] According to a preferred embodiment, the host material in the light-emitting layer can be selected to be a combination of a first compound and a second compound.

[0017] [Rule 26 correction 25.12.2025] Preferably, the first chemical formula of the first compound is represented as:

[0018] [Rule 26 correction 25.12.2025] Wherein, in the first chemical formula,

[0019] [Rule 26 correction 25.12.2025] X is O or S,

[0020] [Rule 26 correction 25.12.2025] Z is hydrogen, deuterium, substituted or unsubstituted C1to C10alkyl, or substituted or unsubstituted phenyl,

[0021] [Rule 26 correction 25.12.2025] L 1 and L 2 are each independently a single bond or a substituted or unsubstituted C6to C20arylene,

[0022] [Rule 26 correction 25.12.2025] R a , R b , and R 1 to R 7 are each independently hydrogen, deuterium, substituted or unsubstituted C1to C10alkyl, or substituted or unsubstituted C6to C20aryl.

[0023] [Rule 26 correction 25.12.2025] Preferably, the second chemical formula of the second compound is represented as:

[0024] [Rule 26 correction 25.12.2025] Wherein, in the second chemical formula,

[0025] [Amended according to Rule 26 on 25.12.2025] Y 1 and Y 2 each independently is a single bond or a substituted or unsubstituted C6to C20arylene,

[0026] [Amended according to Rule 26 on 25.12.2025] Ar 1 and Ar 2 each independently is a substituted or unsubstituted C6to C20aryl or a substituted or unsubstituted C2to C30heterocyclyl,

[0027] [Amended according to Rule 26 on 25.12.2025] R c and R 8 to R 13 each independently is hydrogen, deuterium, a substituted or unsubstituted C1to C10alkyl, a substituted or unsubstituted C6to C20aryl, a substituted or unsubstituted C2to C30heterocyclyl, a cyano, or a combination thereof,

[0028] [Amended according to Rule 26 on 25.12.2025] m is 0, 1, or 2.

[0029] [Amended according to Rule 26 on 25.12.2025] According to a preferred embodiment, the first host material in the light-emitting layer is selected as Host1, and the second host material is selected as Host2, such that in the combined host materials, the LUMO energy level of Host1 is lower than the LUMO energy level of the light-emitting material tetra-Pt-dbf or tetra-Pt-dbt or the difference between the LUMO energy level of Host1 and the LUMO energy level of the light-emitting material is less than 0.2 eV, wherein,

[0030] [Amended according to Rule 26 on 25.12.2025] Host1 is selected from the following compounds:

[0031] [Amended according to Rule 26 on 25.12.2025] Host2 is selected from the following compounds:

[0032] [Amended according to Rule 26 on 25.12.2025] wherein * is a linkage point,

[0033] [Amended according to Rule 26 on 25.12.2025] *-Y 1 -Ar 1 and *-Y 2 -Ar 2 is one of the following groups:

[0034] [According to Rule 26, the application is amended on December 25, 2025] Preferably, the first compound in the light-emitting layer is selected as Host1-1, and the second compound is selected as Host2-1, so that in the combined host material, the LUMO level of Host1-1 is lower than or close to the LUMO level of the light-emitting material tetra-Pt-dbf or tetra-Pt-dbt, wherein Host1-1 and Host2-1 are represented by the following chemical formula respectively:

[0035] [According to Rule 26, the application is amended on December 25, 2025] The energy level refers to the molecular orbital energy level of an organic molecule, which generally includes the HOMO energy level and the LUMO energy level. The HOMO energy level refers to the energy level of the highest occupied molecular orbital, which is equivalent to the valence band in inorganic semiconductors; the LUMO energy level refers to the energy level of the lowest unoccupied molecular orbital, which is equivalent to the conduction band in inorganic semiconductors. The LUMO energy level of the host material of a general OLED device is higher than that of the light-emitting material, while in the dual-host material used in the present application, the LUMO energy level of at least one host material is lower than or equivalent to that of the light-emitting material, especially when the host material of the light-emitting layer is selected as the combination of Host1-1 and Host2-1, the LUMO energy level of Host1-1 is lower than or close to that of the light-emitting material, so as to protect the excited state of the platinum complex light-emitting material, or reduce the excited state electron density or the negative polaron density on the platinum complex molecule, prevent the platinum complex light-emitting molecule from being destroyed, and thus enhance the service life of the tunable light OLED device.

[0036] [According to Rule 26, the application is amended on December 25, 2025] When the host material of the light-emitting layer is selected as the combination of Host1-1 and Host2-1, the HOMO energy level and the LUMO energy level of the two host materials tetra-Pt-dbf and tetra-Pt-dbt and the two light-emitting materials are shown in the following table:

[0037] [According to Rule 26, the application is amended on December 25, 2025] According to a preferred embodiment, when the host material of the light-emitting layer is selected as the combination of Host1 and Host2, the doping concentration of the light-emitting material tetra-Pt-dbf is limited to 4wt%-20wt%, preferably 6wt%-13wt%, so that the light-emitting device can emit light of different colors at least at two wavelengths; or the doping concentration of the light-emitting material tetra-Pt-dbt is limited to 6wt%-10wt%, so that the light-emitting device can emit light of different colors at least at two wavelengths.

[0038] [Corrected according to Rule 26 25.12.2025] The present application also discloses a high-efficiency, long-life adjustable light organic light-emitting device, comprising: a positive electrode and a negative electrode configured to have a driving voltage on two electrodes; and a plurality of organic layers between the two electrodes, wherein at least one layer of the organic layers is a light-emitting layer, in which two or more host materials are mixed together and doped with a light-emitting material; the light-emitting material is a platinum complex, and it has a monomer emission state and at least one aggregation emission state; the host material in the light-emitting layer is selected as a combination of SF-BCZ and SF-TRZ, wherein SF-BCZ and SF-TRZ are represented by the following chemical formula respectively:

[0039] [Corrected according to Rule 26 25.12.2025] According to a preferred embodiment, in the light-emitting device in which the host material is selected as a combination of SF-BCZ and SF-TRZ, the light-emitting material can be selected as any of the aforementioned light-emitting materials.

[0040] [Corrected according to Rule 26 25.12.2025] According to a preferred embodiment, when the host material of the light-emitting layer is selected as a combination of SF-BCZ and SF-TRZ, the doping concentration of the light-emitting material tetra-Pt-dbf or tetra-Pt-dbt is limited to 4wt%-13wt%, so that the light-emitting device can emit light of different colors at least at two wavelengths.

[0041] [Corrected according to Rule 26 25.12.2025] According to a preferred embodiment, in the plurality of organic layers between the two electrodes, at least one layer of the organic layers is a hole transport layer, at least one layer of the organic layers is an electron blocking layer, and at least one layer of the organic layers is an electron transport layer; at least one layer attached to the positive electrode is a hole injection layer; at least one layer attached to the negative electrode is an electron injection layer.

[0042] [Corrected according to Rule 26 25.12.2025] According to a preferred embodiment, the material of the hole injection layer includes HAT-CN, the material of the hole transport layer includes one or more of TAPC, SF-BCZ, BPBPA, FSF4A, the material of the electron blocking layer includes one or more of SF-TRZ, ANT-BIZ, the material of the electron transport layer includes one or more of DPPyA, ANT-BIZ or other materials with electron transport function, or adopts a structure form in which the electron transport material is doped with Liq material in the electron transport layer, for example, a structure form of ANT-BIZ: Liq 50wt%, and the material of the electron injection layer includes one or more of LiF, Liq, Yb.

[0043] [Amended according to Rule 26 on 25.12.2025] The present application also discloses an application of a luminescent material of an efficient phosphorescent Pt(II) emitter coordinated by a tetradentate [O^N^C^N] ligand as a luminescent material, a combination of a first compound and a second compound or a combination of SF-BCZ and SF-TRZ as a host material to prepare a luminescent layer and a luminescent device, wherein the luminescent device can be used in fixed visual display units, mobile visual display units, lighting units, keyboards, clothing, accessories, clothing accessories, wearable devices, medical monitoring devices, wall papers, tablets, laptops, advertising panels, panel display units, household appliances, office supplies. [Amended according to Rule 26 on 25.12.2025]BRIEF DESCRIPTION OF DRAWINGS

[0044] [Amended according to Rule 26 on 25.12.2025]Figure 1 is a chemical structure diagram of the luminescent material tetra-Pt-dbf and tetra-Pt-dbt of the present application;

[0045] [Amended according to Rule 26 on 25.12.2025]Figure 2 is a synthesis route diagram of the luminescent material tetra-Pt-dbf of a preferred embodiment provided by the present application;

[0046] [Amended according to Rule 26 on 25.12.2025]Figure 3 is a synthesis route diagram of the luminescent material tetra-Pt-dbt of a preferred embodiment provided by the present application;

[0047] [Amended according to Rule 26 on 25.12.2025]Figure 4 (a) to (d) are the normalized EL spectra of device 1 with the specified luminance range (100 to 100,000 cd·m -2 ) under different doping concentrations of tetra-Pt-dbf of 4wt%, 7wt%, 10wt% and 13wt% respectively; (e) is the luminance-EQE curve of device 1 with different doping concentrations; (f) is a structural schematic diagram of device 1 and its energy level diagram;

[0048] [Rule 26 correction 25.12.2025] In FIG. 5, (a) X-ray crystal structure and perspective view of tetra-Pt-dbf with hydrogen atoms omitted (thermal ellipsoids probability level: 30%); (b) UV-Vis absorption and emission spectra of tetra-Pt-dbf in toluene at room temperature and 2-MeTHF at 77 K, where a local magnification is made for 490-540 nm; (c) Emission spectra of tetra-Pt-dbf in mCP thin films with different doping concentrations (2 wt%, 5 wt%, 8 wt%, 12 wt%); (d) Molecular orbital diagram calculation results of the structure-optimized tetra-Pt-dbf monomer and dimer at T1 excited state, and EDA calculation results of [tetra-Pt-dbf]2dimer based on the X-ray crystal structure;

[0049] [Rule 26 correction 25.12.2025] In FIG. 6, (a)-(d) are the normalized EL spectra of device 2 with tetra-Pt-dbf doping concentrations of 4 wt%, 7 wt%, 10 wt%, and 13 wt%, respectively;

[0050] [Rule 26 correction 25.12.2025] In FIG. 7, (a)-(c) are the normalized EL spectra of device 3 with tetra-Pt-dbf doping concentrations of 4 wt%, 6 wt%, and 20 wt%, respectively;

[0051] [Rule 26 correction 25.12.2025] In FIG. 8, (a) Normalized EL spectra of device 3 with tetra-Pt-dbf doping concentration of 7 wt% at 2.4 V, 2.6 V, 2.8 V, 3 V, 4 V, 5 V, 6 V, 7 V; (b) CIE coordinate shift plot of device 3 from 2.4 V to 7.0 V; (c) Relative luminance-operation lifetime plot of device 3 at a constant current density of 60 mA cm-2; (d) Integral area ratio A -2 vs. driving voltage of device 3 with tetra-Pt-dbf emitter, where the solid square represents experimental data, the solid line represents the theoretical fitting result, and the dashed line represents the built-in voltage; agg / mon

[0052] [Rule 26 correction 25.12.2025] In FIG. 9, (a) Voltage-CIE (x, y) plot of device 3; (b) Luminance-EQE plot of device 3; (c) Acceleration factor (n) applicable to device 3;

[0053] [Rule 26 correction 25.12.2025] In FIG. 10, Color change of device 3 at initial luminance and when decaying to 90% of the initial luminance under constant current conditions, where (a) Initial luminance L0= 20290 cd m​-2 ; (b) initial brightness L0= 11063 cd m -2 ;

[0054] [Amended according to Rule 26 25.12.2025] Figure 11 is a plot of the color coordinate change of the device 3 over 100 minutes of operation at different constant voltages, where (a) 2.6 V; (b) 3.0 V; (c) 4.0 V and (d) 6.0 V;

[0055] [Amended according to Rule 26 25.12.2025] Figure 12 (a)-(d) are electroluminescence plots of the device 4 with tetra-Pt-dbt doped at 6 wt%, 7 wt%, 8 wt% and 10 wt%, respectively;

[0056] [Amended according to Rule 26 25.12.2025] Figure 13 depicts the chemical structures of the main organic materials used to construct the light-emitting devices described herein;

[0057] [Amended according to Rule 26 25.12.2025] Figure 14 is a cyclic voltammogram of tetra-Pt-dbf in DMF;

[0058] [Amended according to Rule 26 25.12.2025] Figure 15 is a TGA thermogram of tetra-Pt-dbf (heating rate of 10 °C / min);

[0059] [Amended according to Rule 26 25.12.2025] Figure 16 is (a) UV-Vis absorption spectra and (b) normalized electroluminescence spectra of the Pt-X-4 molecule in toluene (2 x 10 -5 M) at different time periods;

[0060] [Amended according to Rule 26 25.12.2025] Figure 17 is (a) UV-Vis absorption spectra and (b) normalized electroluminescence spectra of the tetra-Pt-dbf molecule in toluene (2 x 10 -5 M) at different time periods. [Amended according to Rule 26 25.12.2025] DETAILED DESCRIPTION

[0061] [Amended according to Rule 26 25.12.2025] The following detailed description is made in connection with the accompanying drawings.

[0062] [Corrected according to Rule 26 25.12.2025] According to one preferred embodiment, the present application discloses a high-efficiency, long-lifetime, tunable light organic light-emitting device, which realizes the stability of the light-emitting device in manufacturing and working by stable device structure and stable emitter, so that the light-emitting device can meet the practical application requirements of human-computer interaction terminal or wearable biomedical equipment.

[0063] [Corrected according to Rule 26 25.12.2025] In one or more embodiments, the emitter used as a dopant in the light-emitting layer is a metal complex with a square planar chemical structure. Preferably, the metal complex is a platinum complex. In one or more embodiments, the emitter is a compound with a Pt[O^N^C^N] structural form.

[0064] [Corrected according to Rule 26 25.12.2025] The present application discloses a series of effective phosphorescent Pt(II) emitters coordinated by tetradentate [O^N^C^N] ligands. In a preferred embodiment, based on the luminescence of such Pt(II) complexes, the light-emitting device can achieve a high EQE of up to 30.2%. Preferably, both tetra-Pt-dbf and tetra-Pt-dbt of the present application (as shown in Figure 1) have the potential to be used as single light-emitting dopants in the manufacturing of voltage-dependent, color-tunable light-emitting devices, because the Pt[O^N^C^N] complex has excellent electroluminescence (EL) performance in both monomer state and aggregated state. Figures 2-3 are the synthesis route diagrams of tetra-Pt-dbf and tetra-Pt-dbt of the present application, respectively.

[0065] [Corrected according to Rule 26 25.12.2025] Preferably, tetra-Pt-dbf and tetra-Pt-dbt have shorter τ and excellent PLQY in both monomer state and aggregated state, so that they can be used as single emitters in CT-OLEDs. Therefore, the present application discloses a stable color-tunable OLED device or light-emitting device with single emitter tetra-Pt-dbf or tetra-Pt-dbt. Further, the device or light-emitting device can adopt a structure of doping the single light-emitting material with a dual host material, by precisely controlling the doping concentration to obtain a CT-OLED device with high efficiency, wide light tuning range and ultra-long service life.

[0066] [Corrected according to Rule 26 25.12.2025] Embodiment 1

[0067] [Corrected according to Rule 26 25.12.2025] According to one preferred embodiment, the present embodiment discloses a light-emitting device with the following device structure, the structure diagram and energy level diagram of which are shown in Figure 4f:

[0068] [Rule 26 correction 25.12.2025] Device 1: ITO / HAT-CN(5nm) / TAPC(30nm) / SF-BCZ(10nm) / SF-BCZ:SF-TRZ:tetra-Pt-dbf(xwt%)(30nm) / SF-TRZ(10nm) / DPPyA(30nm) / LiF(1.2nm) / Al(150nm),

[0069] [Rule 26 correction 25.12.2025] Wherein ITO is a transparent anode; HAT-CN is a hole injection layer; TAPC is a first hole transport layer; SF-BCZ is a second hole transport layer for transporting holes and preventing exciton quenching at the hole and host material interface; SF-TRZ is an electron blocking layer for blocking electrons from the light-emitting layer; DPPyA is an electron transport layer; LiF is an electron injection layer; Al is an aluminum electrode as the cathode of the device. In the emitting layer (EML), SF-BCZ is the host material 1, SF-TRZ is the host material 2, tetra-Pt-dbf is the light-emitting material, and x wt% represents the doping concentration of the light-emitting material, wherein x wt% can be 4wt%~13wt%, and further can be 4wt%, 7wt%, 10wt%, 13wt% of the doping concentration; here, tetra-Pt-dbf is a single emitter.

[0070] [Rule 26 correction 25.12.2025] As shown in Figure 4, the color-tunable EL characteristics of device 1 with different doping concentrations of light-emitting materials can be seen. Specifically, at a low doping concentration of 4wt%, the EL spectrum (as shown in Figure 4a) shows a single peak at 525nm, which can be classified as monomer emission of tetra-Pt-dbf compared with the PL spectrum in Figure 5b. As the brightness increases from 100cd·m -2 to 100000cd·m -2 , these EL spectra remain consistent, keeping the CIE coordinates around (0.342, 0.618) with a deviation of (±0.01, ±0.01). However, as shown in Figures 4b-4d, as the dopant concentration increases from 7wt% to 13wt%, a new emission peak appears near 670nm, which can be classified as aggregate emission of tetra-Pt-dbf compared with the PL spectrum in Figure 5b. As can be seen from Figure 4d, the color-tunable phenomenon can be clearly observed in device 1 with a doping concentration of 13wt%. As can be seen from Table 1, the CIE coordinates move from (0.479, 0.508) at 2.8V to (0.449, 0.533) at 7V. This shows that device 1 of the present application can emit light of different colors at two wavelengths to achieve color tuning.

[0071] [Rule 26 correction 25.12.2025] Table 1 Partial performance of various OLED devices doped with different concentrations of tetra-Pt-dbf

[0072] [Rule 26 correction 25.12.2025] a CIE stands for Commission Internationale de L'Eclairage, which refers to the International Commission on Illumination. The corresponding data in the table is obtained by referring to the chromaticity diagram defined by CIE in 1931.

[0073] [Rule 26 correction 25.12.2025] b The initial luminance is 1000 nits (i.e. 1000 cd m -2 ), the device working time when the luminance decays to 90% of the initial luminance.

[0074] [Rule 26 correction 25.12.2025] c The initial luminance is 100 nits (i.e. 100 cd m -2 ), the device working time when the luminance decays to 90% of the initial luminance.

[0075] [Rule 26 correction 25.12.2025] As shown in Figure 4e, the device 1 with different doping concentrations exhibits high emission efficiency and low efficiency roll-off in the luminance range of 1000-10000 cd·m -2 , among which the device containing 4wt% tetra-Pt-dbf has the highest EQE max of 30.2%. Even at high luminance of 1000 cd·m -2 and 10000 cd·m -2 , the EQE of this device remains at 30.0% and 27.8%, respectively. Its maximum luminance is as high as 148300 cd·m -2 (as shown in Table 1). At the same time, the device containing 13wt% tetra-Pt-dbf not only has a wide color adjustment range, but also exhibits an EQE max as high as 28.1%, and low efficiency roll-off (EQE -2 27.8%, EQE -2 25.0%) at high luminance of 1000 cd·m 1000 and 10000 cd·m 10000 , respectively.

[0076] [Rule 26 correction 25.12.2025] As can be seen, this CT-OLED is one of the most efficient CT-OLEDs, EQE max up to 30% or so, superior to most of the existing CT-OLEDs. Such high EL efficiency can be attributed to the high PLQY of the emitter tetra-Pt-dbf in monomeric and aggregated states. In addition, the good energy level alignment from ETL to EML can reduce the energy barrier and prevent the associated quenching. The short excited state lifetime and high thermal stability of tetra-Pt-dbf also help to suppress the triplet-related annihilation or thermal degradation, thus suppressing the efficiency roll-off at high brightness.

[0077] [Rule 26 correction 25.12.2025] Therefore, the device 1 in this embodiment can not only emit light of different colors at two wavelengths to achieve color adjustment, but also has a higher EQE max , so that its EL efficiency is higher than that of the existing CT-OLEDs.

[0078] [Rule 26 correction 25.12.2025] Embodiment 2

[0079] [Rule 26 correction 25.12.2025] According to a preferred embodiment, the embodiment discloses a light-emitting device with the following device structure:

[0080] [Rule 26 correction 25.12.2025] Device 2: ITO / HAT-CN(5nm) / BPBPA(120nm) / FSF4A(10nm) / SF-BCZ:SF-TRZ:tetra-Pt-dbf(ywt%)(20nm) / ANT-BIZ(10nm) / ANT-BIZ:Liq 50wt%(40nm) / Liq(1.2nm) / Al(100nm),

[0081] [Rule 26 Correction 25.12.2025] Wherein, ITO is a transparent anode; HAT-CN is a hole injection layer; BPBPA is a first hole transport layer; FSF4A is a second hole transport layer for transporting holes and preventing exciton quenching at the hole and host material interface; ANT-BIZ is a first electron transport layer for transporting electrons and blocking holes into non-emitting areas; ANT-BIZ:Liq 50wt% is a second electron transport layer; Liq is an electron injection layer; Al is an aluminum electrode as the cathode of the device. In the emitting layer (EML), SF-BCZ is a host material 1, SF-TRZ is a host material 2, tetra-Pt-dbf is a light-emitting material, and y wt% represents the doping concentration of the light-emitting material, wherein y wt% can be 4wt% to 13wt%, and further can be specifically a doping concentration of 4wt%, 7wt%, 10wt%, 13wt%; here, tetra-Pt-dbf is a single emitter.

[0082] [Rule 26 Correction 25.12.2025] Preferably, as shown in Figure 6 and Table 1, device 2 shows color-tunable EL spectra, good efficiency and operational stability. The EQE of device 2 with different doping concentrations max are all higher than 15%, the LT 90 exceeds 37,000 hours at L0 of 100 cd·m -2 -2. In these devices, assuming an acceleration factor n of 1.75, the device with a doping concentration of 7wt% has a LT -2 of approximately 77772 hours at L0 of 100 cd·m 90 -2. When the doping concentration is increased to 10wt%, a larger color tuning range and longer service life can be achieved, with CIE coordinates moving from (0.476, 0.510) at 2.8V to (0.434, 0.541) at 7V, and the LT 90 is as long as 37789 hours.

[0083] [Rule 26 Correction 25.12.2025] The device 2 of the present embodiment uses SF-BCZ and SF-TRZ as host materials and tetra-Pt-dbf as a light-emitting material, which can enable the light-emitting device to emit light of different colors at two wavelengths when the doping concentration is 4wt% to 13wt%, and the device lifetime LT 90@100nits is approximately between 37000 hours and 77000 hours, which has been greatly improved compared to the service life of conventional color-tunable OLED devices.

[0084] [Rule 26 Correction 25.12.2025] Embodiment 3

[0085] [Amended according to Rule 26 on 25.12.2025] According to a preferred embodiment, in order to further improve the service life of the CT-OLED, the present embodiment discloses a light-emitting device with the following device structure:

[0086] [Amended according to Rule 26 on 25.12.2025] Device 3: ITO / HAT-CN (5 nm) / BPBPA:HAT-CN 3wt% (10 nm) / BPBPA (50 nm) / FSF4A (10 nm) / Host1-1:Host2-1:tetra-Pt-dbf (z wt%)(20 nm) / ET:Liq 50wt% (40 nm) / Yb (1 nm) / Ag (100 nm),

[0087] [Amended according to Rule 26 on 25.12.2025] Wherein, ITO is a transparent anode; HAT-CN is a hole injection layer; BPBPA:HAT-CN is a first hole transport layer; BPBPA is a second hole transport layer; FSF4A is an electron blocking layer, used to prevent electrons from leaving the light-emitting layer; Host1-1+Host2-1 constitute the light-emitting layer, which is also doped with a certain proportion of light-emitting material tetra-Pt-dbf; while the electron transport layer is selected to be a structure of electron transport material doped Liq material, such as ET:Liq 50wt%, wherein the electron transport material can also be selected from one of ANT-BIZ, DPPyA, etc.; Yb is used as an electron injection layer, and Ag is used as a cathode. In the light-emitting layer (EML), Host1-1 is the host material 1, Host2-1 is the host material 2, and tetra-Pt-dbf is the light-emitting material, and z wt% represents the doping concentration of the light-emitting material, wherein z wt% can be 4wt%~20wt%, and further can be 4wt%, 6wt%, 7wt%, 20wt% of the doping concentration; here, tetra-Pt-dbf is a single emitter.

[0088] [Amended according to Rule 26 on 25.12.2025] Preferably, as shown in Figure 7, for device 3, when the doping concentration is 4wt%, the device has no adjustable light effect; when the light-emitting material doping concentration is increased to 6wt%, the device begins to show obvious changes in the spectrum; when the doping concentration is increased to 20wt%, the device basically emits deep red light in the aggregate state, and the light adjustment effect basically disappears. Therefore, the doping concentration of the light-emitting material can be selected to be 4wt%~20wt%, and further preferably 6wt%~13wt%.

[0089] [Amended according to Rule 26, 25.12.2025] Figure 8a shows the different EL spectra of device 3 with a doping concentration of 7 wt% at driving voltages of 2.4 V, 2.6 V, 2.8 V, 3 V, 4 V, 5 V, 6 V, and 7 V. At the low voltage of 2.4–2.6 V, the aggregate emission of tetra-Pt-dbf (peak at approximately 670 nm) is dominant, and as the voltage increases, the stable and enhanced single-emission (peak at approximately 525 nm) gradually becomes dominant. As shown in Table 1 and Figure 8b, device 3 has a wide color tuning range, with the CIE coordinates shifting from (0.510, 0.475) at 2.4 V to (0.379, 0.584) at 7.0 V. As shown in Figures 8c and 9, at L0 of 20290 cd·m -2 At that time, its working life LT 90 The degradation acceleration time was 48.1 hours, and the degradation acceleration factor n calculated using the exponential decay model was 1.7485. The brightness was 10000 cd·m. -2 1000 cd·m -2 and 100 cd·m -2 In the case of LT 90 The lifetimes are approximately 166 hours, 9288 hours, and 520536 hours respectively, which is more than 20 times longer than the most advanced CT-OLEDs currently available, and even comparable to the lifetimes of most existing stable monochromatic OLED devices. This demonstrates that the tunable color light-emitting device of this invention, employing the aforementioned combination of host and luminescent materials, overcomes the technical bottleneck that the lifetime of CT-OLEDs is far shorter than that of monochromatic OLEDs. It enables the lifetime of CT-OLEDs to reach or even exceed that of monochromatic OLEDs, resolving the technical bias in the field that did not consider the impact of intermolecular π-π stacking interactions on device lifetime and stability during the combination of host and luminescent materials. This opens up a research and development approach that utilizes the π-π stacking interactions in luminescent materials to incorporate specific host materials to significantly increase the lifetime of tunable color light-emitting devices.

[0090] [Revised according to Rule 26, 25.12.2025] As shown in Figure 10 and Table 2, at 30 or 60 mA·cm -2The driving voltage of device 3 only shows a slight increase of 0.6 V or 0.4 V, resulting in a negligible shift of CIEx and CIEy of 0.008% or 0.004% and 0.006% or 0.004%, respectively, at a constant driving current density, which indicates that the stability of device 3 is excellent. Further, Figure 11 shows the color coordinate change curve of the luminescence of device 3 of the present application under constant voltage for 100 min. It can be seen from the figure that the color coordinates of device 3 do not change substantially, indicating that the stability of the device is excellent. However, the luminescent color of the existing CT-OLED will change after a long time of operation under constant current or voltage, which is difficult to achieve the stability of the luminescent device of the present application. Therefore, the luminescent device of the present application has excellent practical value. On the other hand, considering the estimated service life (LT 90@100nits = 520536 hours) of device 3, no significant device degradation will occur when device 3 is actually used at a low brightness of 100 cd m -2 . Therefore, the color-tunable performance of device 3 of the present application is not substantially affected after long-term use.

[0091] [Corrected according to Rule 26 on 25.12.2025] Table 2 shows the voltage and color coordinate CIE change of device 3 before and after device decay under constant current

[0092] [Corrected according to Rule 26 on 25.12.2025] Compared with the CT-OLED (LT 90@100nits = 19105 hours) using Pt-X-4 as an emitter described in the prior art CN116602071A, the CT-OLED of the present application using tetra-Pt-dbf as an emitter not only has a service life that is tens of times longer than that of the CT-OLED of the prior art, but also shows superior device stability. The superior running stability of the CT-OLED of the present application can be attributed to the short excited state lifetime (τ < 2 us) of tetra-Pt-dbf in the monomer state and the aggregated state. Due to the "heavy atom effect", phosphorescent metal organic emitters usually have a short triplet excited state lifetime, which promotes the rapid radiative decay from the triplet excited state to the ground state. This largely suppresses the triplet state-related annihilation, not only reducing the efficiency roll-off under high current density, but also prolonging the device lifetime. The monomer emission and aggregated emission of tetra-Pt-dbf both have a short excited state lifetime, which is different from other complexes that only have a short excited state lifetime in the monomer state or the aggregated state.

[0093] [Corrected according to Rule 26 on 25.12.2025] In order to better explain this excellent color-tunable mechanism, the "capture and energy transfer model" can be applied to simulate the experimental data, wherein the model can be represented by the following formula:

[0094] [According to Rule 26 Correction 25.12.2025] The above equation is derived for single-layer OLEDs and can be applied to multi-layer OLEDs for color-tunable OLED interpretation. Unlike in previous literature reports, where only the intensity ratio of different emission bands is used, in the present invention, the integrated area ratio A agg / mon is used to describe the emission ratio q(U) in the above equation. This method is adopted because the full width at half maximum (FWHM) of the aggregated emission band is larger than that of the monomer emission band, which would lead to severe bias in the simulation process if q(U) is described by the intensity ratio. In the above equation, D is the diffusion coefficient of trapped electrons, μ is the mobility of the carriers, d is the thickness of the EML, L T is the average diffusion distance of the carriers before reaching the trapping center, U is the driving voltage, and U0 is the built-in electric field. Further, D / μ is the Einstein relation describing the ratio between the diffusion rate and the mobility. By fitting the experimental data using the above equation, the curve fitting matches the experimental data with a correlation coefficient R 2 of 0.996, as shown in Figure 8d. Here, the present invention obtains a built-in field U0 of 2.26 V and an Einstein relation D / μ of 2.0, which is close to that reported in conventional organic systems. The experimental data are highly consistent with the fitted curve, indicating that this color-tunable phenomenon can be the result of competition between the charge trapping and direct energy transfer mechanisms.

[0095] [According to Rule 26 Correction 25.12.2025] Embodiment 4

[0096] [According to Rule 26 Correction 25.12.2025] According to a preferred embodiment, the present embodiment discloses a light-emitting device with the following device structure:

[0097] [According to Rule 26 Correction 25.12.2025] Device 4: ITO / HAT-CN (5 nm) / BPBPA:HAT-CN 3 wt% (10 nm) / BPBPA (50 nm) / FSF4A (10 nm) / Host1-1:Host2-1:tetra-Pt-dbt (a wt%)(20 nm) / ET:Liq 50 wt% (40 nm) / Yb (1 nm) / Ag (100 nm),

[0098] [According to Rule 26, correct 25.12.2025] wherein ITO is a transparent anode; HAT-CN is a hole injection layer; BPBPA: HAT-CN is a first hole transport layer; BPBPA is a second hole transport layer; FSF4A is an electron blocking layer for preventing electrons from leaving the light-emitting layer; Host1-1+Host2-1 constitutes a light-emitting layer, which is further doped with a certain proportion of light-emitting material tetra-Pt-dbt; and the electron transport layer is selected to be a structure of electron transport material doped Liq material, such as ET:Liq 50wt%, wherein the electron transport material can also be selected from one of ANT-BIZ, DPPyA, etc.; Yb is used as an electron injection layer, and Ag is used as a cathode. In the light-emitting layer (EML), Host1-1 is a host material 1, Host2-1 is a host material 2, tetra-Pt-dbt is a light-emitting material, and a wt% represents the doping concentration of the light-emitting material, wherein a wt% can be 6wt%-10wt%, and further can be specifically 6wt%, 7wt%, 8wt%, 10wt% of the doping concentration; here, tetra-Pt-dbt is a single emitter.

[0099] [According to Rule 26, correct 25.12.2025] Figure 12 shows the electroluminescence diagrams of device 4 doped with different concentrations of tetra-Pt-dbt at driving voltages of 6wt%, 7wt%, 8wt% and 10wt% respectively. When the doping concentration of the light-emitting material tetra-Pt-dbt is in the range of 6wt%-10wt%, the device 4 at a driving voltage of 2.6-10V can emit light of different colors at two wavelengths to achieve color adjustment. Therefore, the CT-OLED of the present application can simultaneously realize monomer (high energy band) emission and aggregation (low energy band) emission using a single light-emitting material tetra-Pt-dbf or tetra-Pt-dbt, and the excited state lifetime is short, thereby prolonging the service life of the light-emitting device. Taking tetra-Pt-dbf as an example, compared with the emitter Pt-X-4 (T d =430℃) used in the prior art CN116602071A, the tetra-Pt-dbf of the present application has higher thermal stability (T d= 508 °C). In addition, due to the stronger intermolecular π-π stacking interaction, the dimer [tetra-Pt-dbf]2 has a higher intermolecular bond energy (-52.0 kcal / mol), for example, higher than -44.2 kcal / mol of Pt-X-4, which indicates that tetra-Pt-dbf aggregates have higher chemical stability, which can inhibit the decomposition of tetra-Pt-dbf aggregates in OLED devices, so that the devices manufactured using tetra-Pt-dbf reduce thermal degradation and improve stability. Further, the same is true for tetra-Pt-dbt.

[0100] [Amended according to Rule 26 25.12.2025] In addition, unlike existing CT-OLEDs using multiple emitters, the CT-OLEDs of the present application using a single emitter can basically avoid the "color aging problem" and eliminate quenching between different dopants in the EML, thereby prolonging the service life. The CT-OLEDs of the present application are doped with a single tetra-Pt-dbf or tetra-Pt-dbt emitter, have a wider color adjustment range, higher EQE, lower efficiency roll-off, and excellent operating stability. This indicates that CT-OLEDs using planar luminescent Pt(II) complexes as a single emitter have broad application prospects, for example, in smart lighting, decoration, and wearable biomedical sensors.

[0101] [Amended according to Rule 26 25.12.2025] Example 5

[0102] [Amended according to Rule 26 25.12.2025] Table 3 shows the relevant performance data of the light-emitting device of the present application when using different host material combinations.

[0103] [Amended according to Rule 26 25.12.2025] Table 3 shows the relevant performance data of the light-emitting device of the present application when using different host material combinations.

[0104] [Amended according to Rule 26 25.12.2025] Preferably, the chemical structures of Host1-2 to Host1-5 are as follows:

[0105] [Amended according to Rule 26 25.12.2025] Preferably, the chemical structures of Host1-2 to Host1-5 are as follows:

[0106] [Amended according to Rule 26 25.12.2025] Experimental section

[0107] [Amended according to Rule 26 25.12.2025] Materials: HAT-CN, TAPC, ANT-BIZ, Al, Yb, Ag and LiF were purchased from Luminescence Technology Corp, BPBPA, DPPyA, SF-BCZ, SF-TRZ, Host1 and Host2 were purchased from PURI Materials. All these materials were used as received without further purification. tetra-Pt-dbf was synthesized and purified by gradient sublimation before use. The chemical structures of all organic materials are shown in Figure 13.

[0108] [Amended according to Rule 26 25.12.2025] PLQY measurements and electrochemical measurements: Steady-state emission spectra of solution, glassy and solid state complexes were investigated with a Horiba Fluorolog-3 spectrophotometer. Emission of glassy state was measured in 2-methyltetrahydrofuran at 77 K. Solutions for photophysical investigations were degassed by using a high vacuum line in a two-compartment cell and subjected to five freeze-pump-thaw cycles. Glassy and solid state samples were placed in quartz tubes (4 mm inner diameter) in a liquid nitrogen Dewar with a quartz window for recording. The emission quantum yields of samples in thin films and solutions were measured using a Hamamatsu C11347 Quantaurus-QY absolute PL quantum yield measurement system, which were prepared by drop-casting from chlorobenzene solutions containing PMMA composites (2-12 wt%) at 80 °C to evaporate the solvent to give a semi-transparent thin film. Emission lifetime measurements were performed on a Quanta Ray GCR 150-10 pulsed Nd:YAG laser system. Errors of ±1 nm for λ values, ±10% for τ values and ±10% for Φ values were estimated. Cyclic voltammetry measurements were performed on a CHI620E electrochemical analyzer / workstation with a conventional three-compartment cell. A 0.1 M (nBu4N)-PF6 solution in DMF was used as the supporting electrolyte for electrochemical measurements. All solutions used in electrochemical measurements were degassed by argon bubbling and measurements were carried out at room temperature. A saturated calomel electrode was used as the reference electrode, a glassy carbon electrode as the working electrode, a platinum wire as the counter electrode and ferrocene as the internal reference.

[0109] [Amended according to Rule 26 25.12.2025] Device fabrication and characterization: Indium tin oxide (ITO) coated glass with a sheet resistance of 10 Ω / sq was used as anode substrate. The patterned ITO substrate was cleaned with detergent, rinsed with deionized water, acetone and isopropanol, and then dried in an oven in a cleanroom for 1 h. The glass slide was further treated in an ultraviolet-ozone chamber for 5 min. OLEDs were fabricated in a Kurt J. Lesker SPECTROS vacuum deposition system with a base pressure of 10 -8mBar. In the vacuum chamber, the organic materials were sequentially thermally deposited at a rate of 0.02-0.1 nm s -1 . The light-emitting layer doping process was achieved using co-deposition technique. LiF (or Liq) and Yb were thermally deposited at a rate of 0.03 nm s -1 . Al or Ag was thermally deposited from a metal source of the vacuum deposition system at a rate of 0.2 nm s -1 . The film thickness was measured in situ using a calibrated oscillating quartz crystal sensor.

[0110] [Amended according to Rule 26 25.12.2025] EL spectra, J-L-V characteristics, CIE coordinates, CRI, EQE, CE and PE were measured using Keithley 2400 source meter and absolute external quantum efficiency measurement system (C9920-12, Hamamatsu Photonics). EL distribution was measured with an angle-dependent device test system (C9920-11, Hamamatsu Photonics). The OLEDs were encapsulated in a 200 nm thick AI2O3 film, which was obtained by atomic layer deposition (ALD) in a Kurt J. Lesker SPECTROS ALD system.

[0111] [Amended according to Rule 26 25.12.2025] Mass spectra (ESI) were recorded on a Bruker Impact II QT mass spectrometer. Elemental analysis was performed at the Institute of Chemistry, Chinese Academy of Sciences.

[0112] [Amended according to Rule 26 25.12.2025] Some experimental results are shown below:

[0113] [Amended according to Rule 26 25.12.2025] Preferably, the X-ray crystal structure of tetra-Pt-dbf is shown in Figure 5a, and the selected bond lengths, bond angles and crystallographic data are summarized in Tables 4-5. Two tetra-Pt-dbf molecules are arranged in a head-to-head direction, with a Pt-Pt distance of In the crystal structure, intermolecular π-π interactions between each pair of tetra-Pt-dbf molecules can be observed, with a molecular face-to-face distance of

[0114] [Amended according to Rule 26 25.12.2025] Table 4 Partial bond lengths and bond angles (°) of tetra-Pt-dbf

[0115] [Amended according to Rule 26 25.12.2025] Table 5 Crystallographic data of tetra-Pt-dbf​

[0116] [Amended in accordance with Rule 26 25.12.2025] Preferably, the electrochemical properties of tetra-Pt-dbf were investigated by cyclic voltammetry (CV) in N,N-dimethylformamide (DMF), the electrochemical data of which are shown in Figure 14. For this complex, one reduction peak was observed at -1.58 V (E red ), and one irreversible oxidation wave at 0.79 V (E ox ). Both the reduction peak and the irreversible oxidation wave are due to the ligand-centered reaction of the O^N^C^N molecule. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energy levels of the complex were estimated from the onset oxidation and reduction potentials at -5.12 eV and -2.74 eV, respectively. The photophysical data of tetra-Pt-dbf are shown in Table 6.

[0117] [Amended in accordance with Rule 26 25.12.2025] Table 6 Photophysical data of tetra-Pt-dbf

[0118] [Amended in accordance with Rule 26 25.12.2025] Figure 5b depicts the UV-Visible absorption spectrum of the complex in toluene solution. The strong absorption band (ε > 4 x 10 4 dm 3 · mol -1 · cm -1 ) at wavelengths below 320 nm corresponds to the ligand-internal π-π * transition of the O^N^C^N ligand. The relatively weak absorption bands (ε = (0.076 - 1.2) x 10 4 dm 3 · mol -1 · cm -1 ) above 400 nm can be attributed to mixed singlet ligand-internal charge transfer (ILCT) and singlet metal-to-ligand charge transfer (MLCT) transitions. tetra-Pt-dbf exhibits a strong yellow-green (λ max = 529 nm) emission in deoxygenated toluene with an emission lifetime τ of 2.44 us and an emission quantum yield as high as 0.82. The structureless yellow-green emission band (λ max = 529 nm) of tetra-Pt-dbf indicates that the emissive excited state has a mixed MLCT / ILCT character.

[0119] [Rule 26 correction 25.12.2025] Different concentrations of tetra-Pt-dbf were doped into mCP thin films to study the solid-state photophysical properties of this complex. As shown in Figure 5c, all thin films exhibited strong emission with a maximum ranging from 523 nm (2 wt%) to 526 nm (12 wt%) due to the monomeric emission of tetra-Pt-dbf. However, as the doping concentration increased from 2 wt% to 12 wt%, another low-energy emission (λ max = 657-665 nm) gradually developed, which is attributed to the aggregated triplet metal-metal-ligand charge transfer (MMLCT) emission. The tetra-Pt-dbf / mCP thin films exhibited high PLQY (e.g., 0.66 for 12 wt% doping concentration and 0.87 for 2 wt% doping concentration) and shorter τ for the emission bands (e.g., τ = 2.10-1.34 us for the 523-526 nm emission band and τ = 1.61-1.13 us for the 657-667 nm emission band), showing good photoluminescence performance in both monomeric and aggregated states.

[0120] [Rule 26 correction 25.12.2025] Since the stability of the solid-state complex is closely related to the intermolecular interaction, the present invention performed energy decomposition analysis (EDA) on the dimer [tetra-Pt-dbf]2. The EDA results showed that the dimer [tetra-Pt-dbf]2 has a strong intermolecular bonding energy of -52.0 kcal / mol (as shown in Figure 5d). The ground state S0 structure and the lowest triplet excited state T1 structure of the dimer [tetra-Pt-dbf]2 were optimized. The calculation of the dimer [tetra-Pt-dbf]2 showed that the Pt-Pt distance of the T1 state was reduced compared to . The molecular orbital (MO) diagram of the monomeric tetra-Pt-dbf and the dimer [tetra-Pt-dbf]2 of the T1 state optimized structure is shown in Figure 5d. For the monomeric tetra-Pt-dbf, the Pt-5dz 2 orbital is the HOMO-5. After dimerization, the short Pt-Pt contact distance of the dimer [tetra-Pt-dbf]2 in the T1 state results in a large energy splitting between the two Pt-5dz 2 orbitals. Such a large energy splitting will σ*(5dz 2) The orbitals are raised to the HOMO in the dimer [tetra-Pt-dbf]2, while the LUMO is mainly localized on the ligand. Therefore, the excited state of tetra-Pt-dbf aggregate is essentially a metal-metal-ligand charge transfer (MMLCT). The calculated emission energy of the dimer [tetra-Pt-dbf]2 in the T1 state is 1.67 eV, which is basically consistent with the 1.77 eV emission energy of the OLED device observed experimentally.

[0121] [According to Rule 26 Correction 25.12.2025] Preferably, the present application studies the thermal stability of tetra-Pt-dbf by thermogravimetric analysis method, and the decomposition temperature T d of the complex is 508℃ (as shown in Figure 15), wherein T d is defined as 5wt% loss. It is shown in Figure 15 that tetra-Pt-dbf has excellent thermal stability. Compared with a single emitter Pt-X-4 (T d = 430℃) described in the prior art CN116602071A, tetra-Pt-dbf has a higher decomposition temperature, indicating that the dibenzo[b,d]furan substitution can enhance the thermal stability of the Pt emitter.

[0122] [According to Rule 26 Correction 25.12.2025] Preferably, the present application further compares the molecular stability of tetra-Pt-dbf and the existing Pt-X-4 under continuous irradiation of 455 nm LED (power is 25W) in toluene, wherein the ultraviolet-visible absorption spectrum and emission spectrum as shown in Figures 16 and 17 are obtained. As can be seen from the figures, the ultraviolet-visible absorption spectrum of tetra-Pt-dbf remains almost unchanged within 420 minutes, while the ultraviolet-visible absorption spectrum of Pt-X-4 shows obvious changes; the PL spectrum of tetra-Pt-dbf at 0 minutes / 420 minutes also remains unchanged, while the PL spectrum of Pt-X-4 at 0 minutes / 420 minutes also shows significant changes. It can be seen therefrom that the tetra-Pt-dbf selected by the present application has better molecular stability, so that the OLED device prepared by using the complex has better stability. Similarly, it can be obtained that the OLED device prepared by using tetra-Pt-dbt also has better stability.

[0123] [Rule 26 Correction 25.12.2025] As shown in Table 6, tetra-Pt-dbf has higher PLQYs, ranging from 0.66 to 0.87; while the PLQYs of the existing Pt-X-4s are much lower, specifically, all of them are lower than 0.60. This is because the dibenzofuran unit of tetra-Pt-dbf can make the tetra-Pt-dbf molecular aggregate have a relatively rigid structure, thereby reducing the non-radiative decay of the 3MMLCT excited state of tetra-Pt-dbf. Further, the dibenzothiophene unit of tetra-Pt-dbt can also have similar properties to reduce the non-radiative decay of the 3MMLCT excited state of tetra-Pt-dbt. Therefore, the light-emitting device of the present application using tetra-Pt-dbf or tetra-Pt-dbt as a light-emitting material can have a super-long lifetime while also having a higher EQE than the existing Pt-X-4 CT-OLEDs max Table 7 is a comparison table of the CT-OLEDs of the present application and the existing partial CT-OLEDs.

[0124] [Rule 26 Correction 25.12.2025] Table 7 Comparison table of the CT-OLEDs of the present application and the existing partial CT-OLEDs

[0125] [Rule 26 Correction 25.12.2025] Note: The data of No. 1 CT-OLED device is that of the present application, and the data of No. 2-10 CT-OLED devices are taken from the following references, respectively:

[0126] [Rule 26 Correction 25.12.2025] a) M. Mao, T.-L. Lam, W.-P. To, X. Lao, W. Liu, S. Xu, G. Cheng, C.-M. Che, Adv. Mater. 2021, 33, 2004873;

[0127] [Rule 26 Correction 25.12.2025] b) G. Cheng, K. T. Chan, W.-P. To, C.-M. Che, Adv. Mater. 2014, 26, 2540-2546;

[0128] [Rule 26 Correction 25.12.2025] c) C. Zhang, D. Zhang, Z. Bin, Z. Liu, Y. Zhang, H. Lee, J. H. Kwon, L. Duan, Adv. Mater. 2021, 2103102;

[0129] [Corrected according to Rule 26 25.12.2025] d) S. Ying, Y. Wu, Q. Sun, Y. Dai, D. Yang, X. Qiao, J. Chen, D. Ma, Appl. Phys. Lett. 2019, 114, 033501 ;

[0130] [Corrected according to Rule 26 25.12.2025] e) J. H. Koo, S. Jeong, H. J. Shim, D. Son, J. Kim, D. C. Kim, S. Choi, J.-I. Hong, D.-H. Kim, ACS nano. 2017, 11, 10032-10041;

[0131] [Corrected according to Rule 26 25.12.2025] f) S. Liu, R. Wu, J. Huang, J. Yu, Appl. Phys. Lett. 2013, 103, 133307;

[0132] [Corrected according to Rule 26 25.12.2025] g) M. T. Schwab, M. Kliem, S. Hofmann, K. Leo, M. C. Gather, Light: Sci. & Appl. 2015, 4, DOI: 10.1038 / lsa.2015.20;

[0133] [Corrected according to Rule 26 25.12.2025] h) G. Mu, T. Rao, Y. Qi, S. Ma, Q. Hao, M. Chen, X. Tang, Adv. Funct. Mater. 2023, 2301280;

[0134] [Corrected according to Rule 26 25.12.2025] i) W. Sun, S. Jiao, S. Li, D. Zhang, X. Xia, L. Zhou, Adv. Optical Mater. 2023, 11, 2300902.

[0135] [Corrected according to Rule 26 25.12.2025] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can think of various solutions under the inspiration of the disclosure of the present application, and these solutions also belong to the disclosed range of the present application and fall within the protection scope of the present application.

Claims

1. [Amended according to Rule 26 25.12.2025] A high efficiency, long lifetime, dimmable organic light emitting device, characterized in that, It comprises: a light emitting layer in which two or more host materials are mixed together and doped with a light emitting material; wherein the light emitting material is a platinum complex and has a monomer emission and at least one aggregate emission; wherein at least one host material contains a triazine group and has a LUMO energy level lower than the LUMO energy level of the light emitting material or a difference between the LUMO energy levels of both is less than 0.2 eV.

2. The light emitting device of claim 1, wherein The light emitting material in the light emitting layer is selected to be an efficient phosphorescent Pt(II) emitter coordinated by a tetradentate [O^N^C^N] ligand, wherein the emitter is represented by the following chemical formula: wherein in the chemical formula, X is independently a 5- or 6-membered heterocycle, R1-R3 are independently selected from the group consisting of hydrogen, halogen, hydroxyl, unsubstituted alkyl, substituted alkyl, cycloalkyl, unsubstituted aryl, substituted aryl, acyl, alkoxy, acyloxy, amino, nitro, acylamino, aralkyl, cyano, carboxyl, mercapto, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl, or alkoxycarbonyl group, R4 is independently selected from the group consisting of hydrogen, halogen, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, sulfonyl, phosphine, and combinations thereof, each pair of adjacent R groups in R1-R3 is independently one or two independent groups or atoms or selected to form a 5- to 6-membered ring, R1-R3 represent mono-, di-, tri-, tetra-substitution or no substitution.

3. The light emitting device according to claim 1 or 2, characterized in that R4 is independently selected from the group consisting of dibenzofuranyl or dibenzothiophenyl.

4. [Amended according to Rule 26 25.12.2025] The light emitting device according to any one of claims 1 to 3, characterized in that, The light emitting material in the light emitting layer is selected as tetra-Pt-dbf or tetra-Pt-dbt, wherein tetra-Pt-dbf and tetra-Pt-dbt are respectively represented by the following chemical formula:

5. [Amended according to Rule 26 25.12.2025] The light emitting device according to any one of claims 1 to 4, characterized in that, The host materials in the light emitting layer can be selected as a combination of a first compound and a second compound, wherein, The first chemical formula of the first compound is represented as: wherein in the first chemical formula, X is O or S, Z is hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, or substituted or unsubstituted phenyl, L 1 and L 2 each independently is a single bond or a substituted or unsubstituted C6to C20arylene, R a R b and R 1 To R 7 Each is independently hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl or substituted or unsubstituted C6 to C20 aryl; The second chemical formula of the second compound is represented as: wherein in the second chemical formula, Y 1 and Y 2 each independently is a single bond or a substituted or unsubstituted C6to C20arylene, Ar 1 and Ar 2 each independently is substituted or unsubstituted C6to C20aryl or substituted or unsubstituted C2to C30heterocyclyl, R c and R 8 to R 13 each independently is hydrogen, deuterium, substituted or unsubstituted C1to C10alkyl, substituted or unsubstituted C6to C20aryl, substituted or unsubstituted C2to C30heterocyclyl, cyano, or a combination thereof, m is 0, 1, or 2.

6. [Amended according to Rule 26 25.12.2025] The light emitting device according to any one of claims 1 to 5, characterized in that The first host material in the light emitting layer is selected as Host1 and the second host material is selected as Host2, such that in the combined host materials, the LUMO energy level of Host1 is lower than the LUMO energy level of the light emitting material tetra-Pt-dbf or tetra-Pt-dbt or the difference between the LUMO energy levels is less than 0.2 eV, wherein, Host1 is selected from the following compounds: Host2 is selected from the following compounds: wherein * is a linkage point, * -Y 1 -Ar 1 and * -Y 2 -Ar 2 is one of the following groups:

7. [Amended according to Rule 26 25.12.2025] The light emitting device according to any one of claims 1 to 6, characterized in that, Host1 is Host1-1 and Host2 is Host2-1, and their chemical structures are as follows:

8. [Amended according to Rule 26 25.12.2025] A high efficiency, long lifetime, dimmable organic light emitting device, characterized in that, It comprises: a light emitting layer in which two or more host materials are mixed together and doped with a light emitting material; wherein the light emitting material is a platinum complex and has a monomer emission and at least one aggregate emission; In the light-emitting layer, the host material is selected as a combination of SF-BCZ and SF-TRZ, wherein SF-BCZ and SF-TRZ are respectively represented by the following chemical formula:

9. The light emitting device of claim 8, wherein, The light emitting material in the light emitting layer is selected to be an efficient phosphorescent Pt(II) emitter coordinated by a tetradentate [O^N^C^N] ligand, wherein the emitter is represented by the following chemical formula: wherein in the chemical formula, X is independently a 5- or 6-membered heterocycle, R1-R3 are independently selected from the group consisting of hydrogen, halogen, hydroxyl, unsubstituted alkyl, substituted alkyl, cycloalkyl, unsubstituted aryl, substituted aryl, acyl, alkoxy, acyloxy, amino, nitro, acylamino, aralkyl, cyano, carboxyl, mercapto, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl, or alkoxycarbonyl group, R4is independently selected from the group consisting of hydrogen, halogen, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, sulfonyl, phosphino, and combinations thereof, each pair of adjacent R groups among R1-R3 is independently one or two independent groups or atoms or selected to form a 5-6 membered ring, R1-R3 represent mono-, di-, tri-, tetra-substitution or no substitution.

10. [Amended according to Rule 26 25.12.2025] The light emitting device according to claim 8 or 9, characterized in that, The light emitting material in the light emitting layer is selected as tetra-Pt-dbf or tetra-Pt-dbt, wherein tetra-Pt-dbf and tetra-Pt-dbt are respectively represented by the following chemical formula:

11. [Amended according to Rule 26 25.12.2025] Use of an efficient phosphorescent Pt(II) emitter coordinated by a tetradentate [O^N^C^N] ligand as a light-emitting material, of a combination of a first compound and a second compound or of a combination of SF-BCZ and SF-TRZ as a host material for the preparation of a light-emitting layer and a light-emitting device, characterized in that, wherein, in the chemical formula, The emitter is represented by the following chemical formula: wherein, in the chemical formula, X is independently a 5 or 6 membered heterocycle, R1-R3 are independently selected from the group consisting of hydrogen, halogen, hydroxyl, unsubstituted alkyl, substituted alkyl, cycloalkyl, unsubstituted aryl, substituted aryl, acyl, alkoxy, acyloxy, amino, nitro, amido, aralkyl, cyano, carboxyl, thiol, styryl, aminocarbonyl, carbamoyl, aryloxycarbonyl, phenoxycarbonyl, or alkoxycarbonyl group, R4is independently selected from the group consisting of hydrogen, halogen, alkyl, cycloalkyl, heteroalkyl, aralkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ester, nitrile, sulfonyl, phosphino, and combinations thereof, each pair of adjacent R groups among R1-R3 is independently one or two independent groups or atoms or selected to form a 5-6 membered ring, R1-R3 represent mono-, di-, tri-, tetra-substitution or no substitution. The first chemical formula of the first compound is represented as: wherein, in the first chemical formula, X is O or S, Z is hydrogen, deuterium, substituted or unsubstituted C1 to C10 alkyl, or substituted or unsubstituted phenyl, L 1 and L 2 each independently is a single bond or a substituted or unsubstituted C6to C20arylene, R a , R b , and R 1 are each independently hydrogen, deuterium, substituted or unsubstituted C1to C10alkyl, or substituted or unsubstituted C6to C20aryl; R 7 is hydrogen, deuterium, substituted or unsubstituted C1to C10alkyl, or substituted or unsubstituted C6to C20aryl; The second chemical formula of the second compound is represented as: wherein, in the second chemical formula, Y 1 and Y 2 each independently is a single bond or a substituted or unsubstituted C6to C20arylene, Ar 1 and Ar 2 each independently is substituted or unsubstituted C6to C20aryl or substituted or unsubstituted C2to C30heterocyclyl, R c and R 8 to R 13 each independently is hydrogen, deuterium, substituted or unsubstituted C1to C10alkyl, substituted or unsubstituted C6to C20aryl, substituted or unsubstituted C2to C30heterocyclyl, cyano, or a combination thereof, m is 0, 1, or 2; SF-BCZ and SF-TRZ are represented by the following chemical formulas, respectively: the light emitting layer or the light emitting device can be used in a fixed visual display unit, a mobile visual display unit, a lighting unit, a keyboard, a clothing, a decoration, a clothing accessory, a wearable device, a medical monitoring device, a wall paper, a tablet, a notebook, an advertising panel, a panel display unit, a household appliance, an office appliance.

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