Monoamine compound, charge-transporting material, and organic electroluminescent device

1. An organic electroluminescent device comprising on a substrate an anode, a hole transport layer, an organic light-emitting layer, and a cathode, wherein the organic light-emitting layer contains an organic compound having a pyridine ring, a pyrazine ring, or a triazine ring as a partial structure and the hole transport layer contains a monoamine compound represented by the following formula (I):

wherein R 1 to R 9 represent a hydrogen atom, an aryl group, or an alkyl group; R 1 to R 9 may be the same or different from each other; and R 1 to R 9 may further have an aryl group or an alkyl group as a substituent in the case where R 1 to R 9 are an aryl group or an alkyl group,

wherein the monoamine compound has a molecular weight of 400 to 2500, the organic compound further has a N-phenylcarbazole ring as a partial structure, and the monoamine compound has a partial structure represented by the following formula (I-1) and has a glass transition temperature of 90° C. or higher:

2. The organic electroluminescent device according to claim 1 , wherein the organic light-emitting layer contains a light-emitting material and a host material, and the host material is an organic compound having a pyridine ring, a pyrazine ring, or a triazine ring as a partial structure.

3. The organic electroluminescent device according to claim 2 , wherein the light-emitting material is an organometallic complex.