Since an organic electroluminescence device (in the Description, occasionally, referred to as organic EL device) emitting high-luminance light was reported in 1987 by C. W. Tang, et al. Eastman Kodak Co. (Appl. Phys. Lett., vol. 51, p. 913, 1987), development of materials for the organic EL device and improvement of device structure have rapidly progressed. Recently, practical application of the organic EL device to, for example, a car audio component or the display of a mobile phone has started. Currently, in order to further expand the use of the organic EL (electroluminescence), for example, development of material for improving luminous efficiency and durability and development of full-color display are being actively performed. In particular, in the application of the device to medium-sized panels, large-sized panels, or lightings, it is necessary to further increase luminance by improving luminous efficiency and to establish a method of mass production suitable for enlarging the size of a product.
Regarding a method of mass production of panels, vacuum deposition where a low molecular compound is evaporated under vacuum for forming a thin film on a substrate is conventionally used. However, this method has disadvantages such that: a vacuum facility is necessary, and a difficulty in forming an organic thin film having a uniform thickness increases with the size. Therefore, such a method is not necessarily suitable for mass-producing large-sized panels.
Meanwhile, as methods for readily increasing the size of a product, production processes using a luminescent high molecular weight material, that is, an ink-jetting method and a printing method, have been developed. In particular, the printing method can continuously form films with a large length and is therefore excellent in enlargement of the size of a product and mass productivity.
Recently, in order to expand the use of the organic EL device, material development using a phosphorescent compound having high luminous efficiency has been actively performed (for example, JP 2003-526876 A (Patent Document 1) and JP 2001-247859 A (Patent Document 2)).
Furthermore, JP 2005-314689 A (Patent Document 3) discloses a compound having a structure derived from a siloxane compound as a luminescent high molecular weight complex compound.
[Patent Document 1] JP 2003-526876 A
[Patent Document 2] JP 2001-247859 A
[Patent Document 3] JP 2005-314689 A