An organic electroluminescence device (hereinafter, the term “electroluminescence” is sometimes abbreviated to “EL”) is a spontaneous light emitting device which utilizes the principle that a fluorescent substance emits light by energy of recombination of holes injected from an anode and electrons injected from a cathode when an electric field is applied. Since an organic EL device of the laminate type driven under a low electric voltage was reported by C. W. Tang of Eastman Kodak Company (C. W. Tang and S. A. Vanslyke, Applied Physics Letters, Volume 51, Pages 913, 1987), many studies have been conducted on the organic EL device using organic materials as the constituting materials. Tang et al. used tris(8-quinolinolato)aluminum for the light emitting layer and a triphenyldiamine derivative for the hole transporting layer. Advantages of the laminate structure include that the efficiency of hole injection into the light emitting layer can be increased, that the efficiency of forming excitons which are formed by blocking and recombining electrons injected from the cathode can be increased, and that excitons formed among the light emitting layer can be enclosed. As the device structure of the organic EL device, a two-layered structure having a hole transporting (injecting) layer and an electron transporting and light emitting layer and a three-layered structure having a hole transporting (injecting) layer, a light emitting layer and an electron transporting (injecting) layer are well known. To increase the efficiency of recombination of injected holes and electrons in the device of the laminate type structure, the structure of the device and the process for forming the device have been devised.
Further, as the light emitting material, chelate complexes such as tris(8-quinolinolato)aluminum complexes, coumarine derivatives, tetraphenylbutadiene derivatives, bisstyrylarylene derivatives and oxadiazole derivatives are known. It is reported that light in the visible region ranging from blue light to red light can be obtained by using these light emitting materials, and development of a device exhibiting color images is expected (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
Patent Documents 4 and 5 each disclose a device using a bisanthracene derivative as a light emitting material. Bisanthracene is used as a blue light emitting material, but is insufficient because its efficiency and lifetime do not reach practical levels.
In addition, Patent Documents 6, 7, 8, and 9 each disclose a device using a symmetric pyrene derivative as a light emitting material. Such symmetric pyrene derivative is used as a blue light emitting material, but an improvement in lifetime of a device using the derivative has been requested.
Patent Documents 10, 11, 12, 13, and 14 each disclose a device using a fluoranthene derivative as a light emitting material. Such fluoranthene derivative is used as a blue light emitting material, but an improvement in lifetime of a device using the derivative has been requested.
Patent Document 1: JP-A-08-239655
Patent Document 2: JP-A-07-138561
Patent Document 3: JP-A-03-200889
Patent Document 4: U.S. Pat. No. 3,008,897
Patent Document 5: JP-A-08-12600
Patent Document 6: JP-A-2001-118682
Patent Document 7: JP-A-2002-63988
Patent Document 8: JP-A-2004-75567
Patent Document 9: JP-A-2004-83481
Patent Document 10: JP-A-2002-69044
Patent Document 11: WO 02/085822
Patent Document 12: WO 2005/033051
Patent Document 13: JP-A-10-189247
Patent Document 14: JP-A-2005-68087