Organoelectroluminescent element, and light emission device, display device, and illumination device in which said organoelectroluminescent element is used
摘要
說明書
When the triphenylene derivative according to the present invention is used as the host material of the light-emitting layer of an organoelectroluminescent element or as a charge transport material of a layer adjacent to the light-emitting layer, if there is a large energy gap from the light-emitting material in a thin film state (when the light-emitting material is a phosphorescent material, the lowest excited triplet (T1) energy in a thin film state), this will prevent the emission from being quenched and is advantageous in terms of improving efficiency. On the other hand, from the standpoint of the chemical stability of the compound, it is preferable for the energy gap and the T1 energy not to be too large. The T1 energy in a film state of the triphenylene derivative expressed by General Formula Tp-1 is preferably at least 52 kcal/mol and no more than 80 kcal/mol, more preferably at least 55 kcal/mol and no more than 68 kcal/mol, and even more preferably at least 58 kcal/mol and no more than 63 kcal/mol. When a phosphorescent material is used as a light-emitting material, in particular, it is preferable for the T1 energy to be within the aforementioned range.
The T1 energy can be found from the short wavelength end in measurement of the phosphorescence emission spectrum of a thin film of the material. For example, the material is formed into a film in a thickness of approximately 50 nm on a washed quartz glass substrate by a vacuum vapor deposition method, and an F-7000 Hitachi fluorescence spectrophotometer (Hitachi High-Technologies) is used to measure the phosphorescence emission spectrum of a thin film at liquid nitrogen temperature. The T1 energy can be found by converting the rising wavelength on the short wavelength side of the emission spectrum thus obtained into energy units.
