公开(公告)号：US08519617B2

公开(公告)日：2013-08-27

申请号：US13752589

申请日：2013-01-29

Applicant: Semiconductor Energy Laboratory Co., Ltd.

Inventor： Shunpei Yamaqzaki ,  Junichiro Sakata ,  Ryoji Nomura

IPC: H01L51/54 ,  H01J1/62

CPC classification number: H01L51/52 ,  H01L51/5048 ,  Y10S428/917

Abstract: It is an object of the present invention to provide a light emitting element with a low driving voltage. In a light emitting element, a first electrode; and a first composite layer, a second composite layer, a light emitting layer, an electron transporting layer, an electron injecting layer, and a second electrode, which are stacked over the first electrode, are included. The first composite layer and the second composite layer each include metal oxide and an organic compound. A concentration of metal oxide in the first composite layer is higher than a concentration of metal oxide in the second composite layer, whereby a light emitting element with a low driving voltage can be obtained. Further, the composite layer is not limited to a two-layer structure. A multi-layer structure can be employed. However, a concentration of metal oxide in the composite layer is gradually higher from the light emitting layer to first electrode side.

Abstract translation: 本发明的目的是提供一种具有低驱动电压的发光元件。 在发光元件中，第一电极; 并且包括层叠在第一电极上的第一复合层，第二复合层，发光层，电子传输层，电子注入层和第二电极。 第一复合层和第二复合层各自包括金属氧化物和有机化合物。 第一复合层中的金属氧化物的浓度高于第二复合层中的金属氧化物的浓度，由此可以获得具有低驱动电压的发光元件。 此外，复合层不限于两层结构。 可以采用多层结构。 然而，复合层中的金属氧化物的浓度从发光层逐渐变高到第一电极侧。