Patents Assigned to Semiconductor Energy Larboratory Co., Ltd.
  • Patent number: 7948169
    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.
    Type: Grant
    Filed: June 25, 2010
    Date of Patent: May 24, 2011
    Assignee: Semiconductor Energy Larboratory Co., Ltd.
    Inventors: Shunpei Yamazaki, Junichiro Sakata, Ryoji Nomura