| 摘要 |
PROBLEM TO BE SOLVED: To provide an organic electroluminescent element that has a high luminous efficiency and high heat resistance. SOLUTION: A hole transport layer is formed on a positive electrode and phosphorescence emission molecules such as Ir(ppy)3 are doped on this hole transport layer and a luminous layer is made. An electron transport layer is formed on this luminous layer and a negative electrode is formed on top of it. The host material that constitutes the hole transport layer is a compound having a basic structure as expressed in the formula. Under this structure, the movement of energy to the phosphorescence emission molecules are easy, and as the glass transition temperature is 100 deg.C or more, and organic electroluminescent element having a high luminous efficiency and high heat resistance can be obtained. Further, if a material having the following structure that has an ionization potential of 0.1 eV or more than the hole transport layer is used for the electron transport layer, the luminous efficiency can be further improved. In the formula, R1 and R2 and R3 and R4 and R2 and R3 can wind a ring. Or at least one of R1, R4 and R5 is nitrogen or an aromatic ring, and it is a compound linked with at least another structure through at least the one of the nitrogen or aromatic ring. Or at least one of R1, R4 and R5 is nitorogen or an aromatic ring, and it is a compound linked with at least another structure through the one of nitrogen or aromatic ring and through an alicyclic compound.
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