1. Field of the Invention
The present invention generally relates to an organic light-emitting element and a display device.
2. Description of the Related Art
Several developments have allowed for improvement in the performance of organic light-emitting elements, such as improvements in emission efficiency, color purity of the emitted light, and service life.
Furthermore, a number of acceptor compounds have heretofore been used as constituent materials of organic light-emitting elements, both as charge injection materials and charge transport materials.
The application to organic light-emitting elements of acceptor compounds such as tetracyanoquinodimethane, has been studied.
Tetrafluoro-tetracyanoquinodimethane compounds used as constituent materials of organic light-emitting elements have been reported in APPLIED PHYSICS LETTERS, 2001, Vol. 78, No. 4, January, and ADVANCED FUNCTIONAL MATERIALS, 2001, 11, No. 4, August.
However, when such acceptor compounds are used as constituent materials of organic light-emitting elements, the initial characteristics such as emission efficiency, and endurance characteristics such as luminance degradation caused by long-term emission, may not be sufficient.
Acceptor compounds having a tetracyano structure can form ammonium salts. Methods for manufacturing such acceptor compounds and ammonium salts thereof are described in J. Heterocyclic Chem., 43, 1037 (2006). However, examples of applying such compounds to organic light-emitting elements have not yet been reported.