Provided are an organic compound and an application thereof. The organic compound has a structure represented by Formula I. Through the design of a molecular structure, the organic compound has suitable HOMO and LUMO energy levels, high singlet energy level, good optoelectronic performance, a high glass transition temperature and good thermal stability, easily forms a good amorphous film, and is suitable for the machining and use of an OLED device. The organic compound, when used in the OLED device, may be used as a light-emitting layer material, an electron transport material or a hole blocking material and especially suitable for use as a host material of the light-emitting layer and can effectively improve the luminescence efficiency of the device, improve the device stability, extend lifetime, and reduce an operating voltage and energy consumption so that the OLED device has significantly improved performance such as luminescence efficiency, lifetime and energy consumption.

Provided are an organic compound and an application thereof. The organic compound has a structure represented by Formula I. Through the design of a molecular structure, the organic compound has suitable HOMO and LUMO energy levels, high singlet energy level, good optoelectronic performance, a high glass transition temperature and good thermal stability, easily forms a good amorphous film, and is suitable for the machining and use of an OLED device. The organic compound, when used in the OLED device, may be used as a light-emitting layer material, an electron transport material or a hole blocking material and especially suitable for use as a host material of the light-emitting layer and can effectively improve the luminescence efficiency of the device, improve the device stability, extend lifetime, and reduce an operating voltage and energy consumption so that the OLED device has significantly improved performance such as luminescence efficiency, lifetime and energy consumption.

An embodiment of the present invention provides a method for preparing a phthalonitrile-based compound, comprising: (a) feeding a mixture comprising a phthalic acid-based compound and a nitrile-based compound into a first reaction part to react; (b) transferring a resulting product of step (a) to a second reaction part connected to the first reaction part to react under the condition of 350 to 400° C.; and (c) obtaining a phthalonitrile-based compound at a discharge part connected to the second reaction part, wherein the second reaction part has a length in a fluid flow direction which is 10 times or more of a square root of an average cross-sectional area perpendicular to the fluid flow direction.

An embodiment of the present invention provides a method for preparing a phthalonitrile-based compound, comprising: (a) feeding a mixture comprising a phthalic acid-based compound and a nitrile-based compound into a first reaction part to react; (b) transferring a resulting product of step (a) to a second reaction part connected to the first reaction part to react under the condition of 350 to 400° C.; and (c) obtaining a phthalonitrile-based compound at a discharge part connected to the second reaction part, wherein the second reaction part has a length in a fluid flow direction which is 10 times or more of a square root of an average cross-sectional area perpendicular to the fluid flow direction.

The present invention relates to a an organic electroluminescent device comprising at least one light-emitting layer B comprising at least one host material H.sup.B, at least one thermally activated delayed fluorescence (TADF) material E.sup.B, and at least one small full width at half maximum (FWHM) emitter S.sup.B wherein E.sup.B transfers energy to S.sup.B and S.sup.B emits light with an emission maximum in the wavelength range from 500 nm to 560 nm.

An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer includes, as a first host material, a first compound that includes at least one group represented by a formula (11) below, the first compound being represented by a formula (1) below, the second emitting layer includes a second compound represented by a formula (2A) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer includes, as a first host material, a first compound that includes at least one group represented by a formula (11) below, the first compound being represented by a formula (1) below, the second emitting layer includes a second compound represented by a formula (2A) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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Specific polycyclic compounds, a material for an organic electroluminescence device comprising said specific polycyclic compound, an organic electroluminescence device comprising said specific polycyclic compound, an electronic equipment comprising said organic electroluminescence device, a process for preparing said polycyclic compounds, and the use of said polycyclic compounds in an organic electroluminescence. (Formula I) (I)

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