Semiconductor Energy Laboratory Co., Ltd.

Satoko Shitagaki

Satoshi Seo

Nobuharu Ohsawa

Hideko Inoue

Harue Osaka

Hiroshi Kadoma

Tsunenori Suzuki

Sachiko Kawakami

Kunihiko Suzuki

Hiromi Seo

Takahiro Ushikubo

Takako Takasu

Ryoji Nomura

Hiroko Abe

Hiromi Nowatari

Shunpei Yamazaki

Harue Nakashima

Yasushi Kitano

Toshiki Sasaki

Shogo Uesaka

Masahiro Takahashi

Kyoko Takeda

Yasuhiko Takemura

Yuko Kawata

Takeyoshi Watabe

Hiroko Nomura

Tomoya Yamaguchi

Atsushi Tokuda

Takahiro Ishisone

Masakazu Egawa

Masato Suzuki

Takao Hamada

Yui Yamada

Toshiki Hamada

Takeshi Nishi

Hiroko Yamazaki

Kaori Ogita

Satomi Mitsumori

Kanta Abe

Tomonori Nakayama

Tomoya Hirose

Junichiro Sakata

Hisao Ikeda

Tatsuyoshi Takahashi

Tomoya Aoyama

Daisuke Kumaki

Naoaki Hashimoto

Miyako Morikubo

Objects of the present invention are to provide: a light-emitting element having a long lifetime and good emission efficiency and drive voltage. One embodiment of the invention is a light-emitting element including, between an anode and a cathode, at least a stack structure in which a first layer, a second layer, and a light-emitting layer are provided in order from the anode side. The first layer includes a first organic compound and an electron-accepting compound. The second layer includes a second organic compound having a HOMO level differing from the HOMO level of the first organic compound by from −0.2 eV to +0.2 eV. The light-emitting layer includes a third organic compound having a HOMO level differing from the HOMO level of the second organic compound by from −0.2 eV to +0.2 eV and a light-emitting substance having a hole-trapping property with respect to the third organic compound.

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

A novel organic compound with which the emission characteristics, emission efficiency, and reliability of a light-emitting element can be improved is provided. The organic compound has an imidazo[1,2-f]phenanthridine skeleton and a dibenzothiophene skeleton or a dibenzofuran skeleton bonded through an arylene group. The light-emitting element including the organic compound in a light-emitting layer shows high efficiency and low power consumption.

Organic compound, light-emitting element, light-emitting device, electronic device, and lighting device

A light-emitting element which has low driving voltage and high emission efficiency is provided. The light-emitting element includes, between a pair of electrodes, a hole-transport layer and a light-emitting layer over the hole-transport layer. The light-emitting layer contains a first organic compound having an electron-transport property, a second organic compound having a hole-transport property, and a light-emitting third organic compound converting triplet excitation energy into light emission. A combination of the first organic compound and the second organic compound forms an exciplex. The hole-transport layer contains at least a fourth organic compound whose HOMO level is lower than or equal to that of the second organic compound and a fifth organic compound whose HOMO level is higher than that of the second organic compound.

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

Provided is a light-emitting element with high external quantum efficiency, or a light-emitting element with a long lifetime. The light-emitting element includes, between a pair of electrodes, a light-emitting layer including a guest material and a host material, in which an emission spectrum of the host material overlaps with an absorption spectrum of the guest material, and phosphorescence is emitted by conversion of an excitation energy of the host material into an excitation energy of the guest material. By using the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material, the energy smoothly transfers from the host material to the guest material, so that the energy transfer efficiency of the light-emitting element is high. Accordingly, a light-emitting element with high external quantum efficiency can be achieved.

Light-emitting element

To provide a light-emitting element having high luminous efficiency and to provide a light-emitting device and an electronic device which consumes low power and is driven at low voltage, a carbazole derivative represented by the general formula (1) is provided. In the formula, α, α, α, and αeach represent an arylene group having less than or equal to 13 carbon atoms; Arand Areach represent an aryl group having less than or equal to 13 carbon atoms; Rrepresents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; and Rrepresents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, l, n, and n are each independently 0 or 1.

Carbazole derivative, and light-emitting element, light-emitting device, and electronic device using carbazole derivative

A light-emitting element includes a light-emitting layer including a guest, an n-type host and a p-type host between a pair of electrodes, where the difference between the energy difference between a triplet excited state and a ground state of the n-type host (or p-type host) and the energy difference between a triplet excited state and a ground state of the guest is 0.15 eV or more. Alternatively, in such a light-emitting element, the LUMO level of the n-type host is higher than the LUMO level of the guest by 0.1 eV or more, or the HOMO level of the p-type host is lower than the HOMO level of the guest by 0.1 eV or more.

Light-emitting device

A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting element is provided which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes, in which a combination of the first organic compound and the second organic compound forms an exciplex (excited complex). The light-emitting element transfers energy by utilizing an overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency. Therefore, a light-emitting element having high external quantum efficiency can be obtained.

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.

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

Provided is a light-emitting element which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes. A combination of the first organic compound and the second organic compound forms an exciplex (excited complex). An emission spectrum of the exciplex overlaps with an absorption band located on the longest wavelength side of an absorption spectrum of the phosphorescent compound. A peak wavelength of the emission spectrum of the exciplex is longer than or equal to a peak wavelength of the absorption band located on the longest wavelength side of the absorption spectrum of the phosphorescent compound.

A light-emitting element includes an EL layer between a pair of electrodes. The EL layer contains a first compound and a second compound. The first compound is a phosphorescent iridium metal complex having a LUMO level of greater than or equal to &#x2212;3.5 eV and less than or equal to &#x2212;2.5 eV, and the second compound is an organic compound having a pyrimidine skeleton. The light-emitting element includes an EL layer between a pair of electrodes. The EL layer contains a first compound and a second compound. The first compound is a phosphorescent iridium metal complex having a diazine skeleton, and the second compound is an organic compound having a pyrimidine skeleton.

Light-emitting element, light-emitting device, electronic device, lighting device, and novel organic compound

In a light-emitting element including an EL layer between a pair of electrodes, between an electrode functioning as an anode and a fourth layer having a light-emitting property (light-emitting layer), the EL layer includes at least a first layer having a hole-injecting property (hole-injecting layer), a second layer having a hole-transporting property (first hole-transporting layer), and a third layer having a hole-transporting property (second hole-transporting layer). The absolute value of the highest occupied molecular orbital level (HOMO level) of the second layer is larger than the absolute value of the highest occupied molecular orbital level (HOMO level) of each of the first layer and the third layer. With such a structure, the rate of transport of holes injected from the electrode functioning as an anode is reduced and emission efficiency of the light-emitting element is improved.

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

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Kanagawa, Japan

Satoko Shitagaki