Semiconductor Energy Laboratory Co., Ltd.

Takahiro Ishisone

Satoshi Seo

Nobuharu Ohsawa

Yusuke Nonaka

Shunpei Yamazaki

Tatsuyoshi Takahashi

Shunsuke Hosoumi

Takuya Kawata

Hiromi Seo

Toshiki Sasaki

Yoshiharu Hirakata

Satoko Shitagaki

Takeyoshi Watabe

Hideko Inoue

Takao Hamada

Kunihiko Suzuki

Tomoya Aoyama

Daiki Nakamura

Naoaki Hashimoto

Hiromitsu Kido

Kyoko Takeda

Hideko Yoshizumi

Yui Yamada

Tomoka Hara

Satomi Watabe

Miyako Morikubo

Fumiyasu Seino

A light-emitting element having high luminous efficiency is provided. The light-emitting element includes a first organic compound, a second organic compound, and a third organic compound. The first organic compound and the second organic compound, in combination, are capable of forming an exciplex. The first organic compound is a phosphorescent compound and the third organic compound is a fluorescent compound. Light emitted from the light-emitting element includes light emitted from the third organic compound to which excitation energy is supplied from the exciplex formed by the first organic compound and the second organic compound.

Light-emitting element, display device, electronic device, and lighting device

A light-emitting element with high luminous efficiency is provided. The light-emitting element contains a first organic compound and a second organic compound. The first and second organic compounds form an exciplex. The first organic compound emits no fluorescence but phosphorescence at a temperature ranging from low temperature to normal temperature. The luminescence quantum yield of the first organic compound is higher than or equal to 0% and lower than or equal to 40% at room temperature. Light emitted from the light-emitting element includes light emitted from an exciplex formed by the first organic compound and the second organic compound.

A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

Light-emitting element, light-emitting device, display device, electronic appliance, and lighting device

Emission efficiency of a light-emitting element is improved. The light-emitting element has a pair of electrodes and an EL layer between the pair of electrodes. The EL layer includes a first light-emitting layer and a second light-emitting layer. The first light-emitting layer includes a fluorescent material and a host material. The second light-emitting layer includes a phosphorescent material, a first organic compound, and a second organic compound. An emission spectrum of the second light-emitting layer has a peak in a yellow wavelength region. The first organic compound and the second organic compound form an exciplex.

Light-emitting element, light-emitting device, electronic device, and lighting device

A light-emitting element having high emission efficiency which includes a fluorescent material as a light-emitting substance is provided. A light-emitting element includes a pair of electrodes and an EL layer between the pair of electrodes. The EL layer includes a light-emitting layer. The light-emitting layer includes a host material and a guest material. The host material has a difference of more than 0 eV and less than or equal to 0.2 eV between a singlet excitation energy level and a triplet excitation energy level. The guest material is capable of emitting fluorescence. The triplet excitation energy level of the host material is higher than a triplet excitation energy level of the guest material.

A light-emitting device with high emission efficiency and reliability is provided. The light-emitting device includes a fluorescent light-emitting layer and a phosphorescent light-emitting layer. A host material used in the fluorescent light-emitting layer has a function of converting triplet excitation energy into light emission and a guest material used in the fluorescent light-emitting layer emits fluorescence. The guest material has a molecular structure including a luminophore and a protecting group, and one molecule of the guest material includes five or more protecting groups. The introduction of the protecting groups into the molecule inhibits transfer of triplet excitation energy from the host material to the guest material by the Dexter mechanism. An alkyl group or a branched-chain alkyl group is used as the protecting group. The longest wavelength absorption band in the absorption spectrum of the guest material in the phosphorescent light-emitting layer has an overlap with the emission spectrum of the host material in the phosphorescent light-emitting layer.

Light-emitting device, light-emitting appliance, display device, electronic appliance, and lighting device

A light-emitting device with high emission efficiency and reliability is provided. The light-emitting device includes first and second fluorescent light-emitting layers. A host material used in the first fluorescent light-emitting layer has a function of converting triplet excitation energy into light emission, a guest material used in the first light-emitting layer has a molecular structure including a luminophore and a protecting group, and one molecule of the guest material includes five or more protecting groups. The introduction of the protecting groups into the molecule inhibits transfer of triplet excitation energy by the Dexter mechanism from the host material to the guest material. An alkyl group or a branched-chain alkyl group is used as the protecting groups. The materials are selected such that the triplet excitation energy level of the host material in the second light-emitting layer is lower than the triplet excitation energy level of the guest material in the second light-emitting layer.

A multicolor light-emitting element that utilizes fluorescence and phosphorescence and is advantageous for practical application is provided. The light-emitting element has a stacked-layer structure of a first light-emitting layer containing a host material and a fluorescent substance and a second light-emitting layer containing two kinds of organic compounds and a substance that can convert triplet excitation energy into luminescence. Note that light emitted from the first light-emitting layer has an emission peak on the shorter wavelength side than light emitted from the second light-emitting layer.

Light-emitting element, display module, lighting module, light-emitting device, display device, electronic appliance, and lighting device

An object is to provide a light-emitting element which uses a plurality of kinds of light-emitting dopants and has high emission efficiency. In one embodiment of the present invention, a light-emitting device, a light-emitting module, a light-emitting display device, an electronic device, and a lighting device each having reduced power consumption by using the above light-emitting element are provided. Attention is paid to Förster mechanism, which is one of mechanisms of intermolecular energy transfer. Efficient energy transfer by Förster mechanism is achieved by making an emission wavelength of a molecule which donates energy overlap with a local maximum peak on the longest wavelength side of a graph obtained by multiplying an absorption spectrum of a molecule which receives energy by a wavelength raised to the fourth power.

Light-emitting element, light-emitting device, display device, electronic device, and lighting device

An object is to provide a light-emitting element which uses a plurality of kinds of light-emitting dopants and has high emission efficiency. In one embodiment of the present invention, a light-emitting device, a light-emitting module, a light-emitting display device, an electronic device, and a lighting device each having reduced power consumption by using the above light-emitting element are provided. Attention is paid to Förster mechanism, which is one of mechanisms of intermolecular energy transfer. Efficient energy transfer by Förster mechanism is achieved by making an emission wavelength of a molecule which donates energy overlap with the longest-wavelength-side local maximum peak of a graph obtained by multiplying an absorption spectrum of a molecule which receives energy by a wavelength raised to the fourth power.

A novel functional panel that is highly convenient, useful, or reliable is provided. The functional panel includes a first element, a first reflective film, and an insulating film. The first element includes a first electrode, a second electrode, and a layer containing a light-emitting material; the layer containing a light-emitting material includes a region interposed between the first electrode and the second electrode; the first electrode has a light-transmitting property; and the first electrode has a first thickness. The first electrode is interposed between a region of the first reflective film and the layer containing a light-emitting material, and the first reflective film has a second thickness. The insulating film includes a first opening portion, and the first opening portion overlaps with the first electrode. The insulating film has a first step-like cross-sectional shape, and the first step-like cross-sectional shape surrounds the first opening portion. The first step-like cross-sectional shape includes a first step, and the first step is larger than or equal to a thickness obtained by adding the second thickness to the first thickness.

Functional panel, display device, input/output device, and data processing device

An object of one embodiment of the present invention is to provide a multicolor light-emitting element that utilizes fluorescence and phosphorescence and is advantageous for practical application. The light-emitting element has a stacked-layer structure of a first light-emitting layer containing a host material and a fluorescent substance, a separation layer containing a substance having a hole-transport property and a substance having an electron-transport property, and a second light-emitting layer containing two kinds of organic compounds that form an exciplex and a substance that can convert triplet excitation energy into luminescence. Note that a light-emitting element in which light emitted from the first light-emitting layer has an emission spectrum peak on the shorter wavelength side than an emission spectrum peak of the second light-emitting layer is more effective.

A light-emitting element which uses a plurality of kinds of light-emitting dopants emitting light in a balanced manner and has high emission efficiency is provided. Further, a light-emitting device, a display device, an electronic device, and a lighting device each having reduced power consumption by using the above light-emitting element are provided. A light-emitting element which includes a plurality of light-emitting layers including different phosphorescent materials is provided. In the light-emitting element, the light-emitting layer which includes a light-emitting material emitting light with a long wavelength includes two kinds of carrier-transport compounds having properties of transporting carriers with different polarities. Further, in the light-emitting element, the triplet excitation energy of a host material included in the light-emitting layer emitting light with a short wavelength is higher than the triplet excitation energy of at least one of the carrier-transport compounds.

Provided is a light-emitting element which has an anode, a light-emitting layer over the anode, an electron-transport layer over and in contact with the light-emitting layer, an electron-injection layer over and in contact with the electron-transport layer, and a cathode over and in contact with the electron-injection layer. The light-emitting layer has an electron-transport property, and the electron-transport layer includes an anthracene derivative. The light-emitting layer further includes a phosphorescent substance. This device structure allows the formation of a highly efficient blue-emissive light-emitting element even though the phosphorescent substance has higher triplet energy than the anthracene derivative which directly contacts with the light-emitting layer.

Growing community of inventors

Kanagawa, Japan

Takahiro Ishisone