Light emitting element, light emitting device, and electronic device
First Claim
1. A light emitting element comprising:
- a first layer;
a second layer;
a third layer; and
a fourth layer which are sequentially provided on an anode side between an anode and a cathode,wherein the first layer includes a first phosphorescent compound and a first organic compound that has a hole transporting property,wherein the second layer includes a first fluorescent organic compound and a second organic compound that has a hole transporting property,wherein the third layer includes a second fluorescent organic compound and a first organic compound that has an electron transporting property, andwherein the fourth layer includes a second phosphorescent compound and a second organic compound having an electron transporting property,wherein triplet excitation energy of the second organic compound having a hole transporting property is higher than or equal to triplet excitation energy of the first organic compound having a hole transporting property, andwherein triplet excitation energy of the first organic compound having an electron transporting property is higher than or equal to triplet excitation energy of the second organic compound having an electron transporting property.
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Accused Products
Abstract
An object is to improve luminous efficiency of a light emitting element using triplet exciton energy effectively. Another object is to reduce power consumption of a light emitting element, a light emitting device, and an electronic device. Triplet exciton energy generated in a light emitting layer which exhibits short wavelength fluorescence can be effectively utilized by use of a structure in which the light emitting layers which exhibit short wavelength fluorescence are sandwiched between light emitting layers each including a phosphorescent compound. Further, the emission balance can be improved between the light emitting layer including a phosphorescent compound and the light emitting layer which exhibits fluorescence by the devising of the structure of the light emitting layer which exhibits fluorescence.
158 Citations
39 Claims
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1. A light emitting element comprising:
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a first layer;
a second layer;
a third layer; and
a fourth layer which are sequentially provided on an anode side between an anode and a cathode,wherein the first layer includes a first phosphorescent compound and a first organic compound that has a hole transporting property, wherein the second layer includes a first fluorescent organic compound and a second organic compound that has a hole transporting property, wherein the third layer includes a second fluorescent organic compound and a first organic compound that has an electron transporting property, and wherein the fourth layer includes a second phosphorescent compound and a second organic compound having an electron transporting property, wherein triplet excitation energy of the second organic compound having a hole transporting property is higher than or equal to triplet excitation energy of the first organic compound having a hole transporting property, and wherein triplet excitation energy of the first organic compound having an electron transporting property is higher than or equal to triplet excitation energy of the second organic compound having an electron transporting property. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A light emitting element comprising:
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a first layer on an anode, wherein the first layer includes a first phosphorescent compound and a first organic compound having a hole transporting property; a second layer on the first layer, wherein the second layer includes a first fluorescent organic compound and a second organic compound having an hole transporting property; a third layer on the second layer, wherein the third layer includes a second fluorescent organic compound and a first organic compound having an electron transporting property; and a fourth layer on the third layer, wherein the fourth layer includes a second phosphorescent compound and a second organic compound having an electron transporting property, wherein triplet excitation energy of the second organic compound having a hole transporting property is higher than or equal to triplet excitation energy of the first organic compound having a hole transporting property, and wherein triplet excitation energy of the first organic compound having an electron transporting property is higher then or equal to triplet excitation energy of the second organic compound having an electron transporting property. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A light emitting element comprising:
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a first electrode; a first light emitting unit over the first electrode; a charge generation layer provided over the first light emitting unit; a second light emitting unit over the charge generation layer; and a second electrode over the second light emitting element, wherein each of the first and second light emitting units comprising; a first layer; a second layer over the first layer; a third layer over the second layer; and a fourth layer over the third layer, wherein the first layer includes a first phosphorescent compound and a first organic compound having a hole transporting property, wherein the second layer includes a first fluorescent compound and a second organic compound having a hole transporting property, wherein the third layer includes a second fluorescent compound and a first organic compound having an electron transporting property, wherein the fourth layer includes a second phosphorescent compound and a second organic compound having an electron transporting property, wherein triplet excitation energy of the second organic compound having a hole transporting property is higher than or equal to triplet excitation energy of the first organic compound having a hole transporting property, and wherein triplet excitation energy of the first organic compound having an electron transporting property is higher than or equal to triplet excitation energy of the second organic compound having an electron transporting property. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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Specification