A diamine derivative represented by the following Formula 2: wherein L1 and L2 are same or different from each other, and are each independently selected from the group consisting of an unsubstituted phenylene group and an unsubstituted naphthylene group; wherein Ar1 and Ar3 of the Formula 2 are same or different from each other, and are each independently selected from the group consisting of a phenyl group, a biphenyl group, a naphthyl group, and a phenyl group substituted with -SiRR'R" or -GeRR'R", wherein R, R', and R" are same or different from each other, and are each independently hydrogen, a C 1 ∼ C 20 alkyl group, a C 3 ∼ C 20 cycloalkyl group, a C 6 ∼ C 20 aryl group or a C 5 ∼ C 20 heterocyclic group, wherein Ar2 and Ar4 of the Formula 2 are same or different from each other, and are each independently selected from the group consisting of a phenyl group; a biphenyl group; a naphthyl group; an anthracenyl group; a pyrenyl group; a perylenyl group; a phenyl group substituted with SiRR'R", -GeRR'R", a C 6 ∼ C 20 aryl amine group, or a C 6 ∼ C 20 aryl group; and the following substituents: wherein R, R', and R" are same or different from each other, and are each independently hydrogen, a C 1 ∼ C 20 alkyl group, a C 3 ∼ C 20 cycloalkyl group, a C 6 ∼ C 20 aryl group or a C 5 ∼ C 20 heterocyclic group, wherein in case that Ar2 and Ar4 are selected from the following substituents, Ar2 is the same as Ar4; L1 is the same as L2, and L1 and L2 are an unsubstituted phenylene group or an unsubstituted naphthylene group, and Ar1 is the same as Ar3, and Ar1 and Ar3 are an unsubstituted phenyl group or an unsubstituted naphthyl group: wherein L1 and L2 are same or different from each other, and are each independently selected from the group consisting of an unsubstituted phenylene group and an unsubstituted naphthylene group; wherein Ar1 and Ar3 of the Formula 2 are same or different from each other, and are each independently selected from the group consisting of a phenyl group, a biphenyl group, a naphthyl group, and a phenyl group substituted with -SiRR'R" or -GeRR'R", wherein R, R', and R" are same or different from each other, and are each independently hydrogen, a C 1 ∼ C 20 alkyl group, a C 3 ∼ C 20 cycloalkyl group, a C 6 ∼ C 20 aryl group or a C 5 ∼ C 20 heterocyclic group, wherein Ar2 and Ar4 of the Formula 2 are same or different from each other, and are each independently selected from the group consisting of a phenyl group; a biphenyl group; a naphthyl group; an anthracenyl group; a pyrenyl group; a perylenyl group; a phenyl group substituted with SiRR'R", -GeRR'R", a C 6 ∼ C 20 aryl amine group, or a C 6 ∼ C 20 aryl group; and the following substituents: wherein R, R', and R" are same or different from each other, and are each independently hydrogen, a C 1 ∼ C 20 alkyl group, a C 3 ∼ C 20 cycloalkyl group, a C 6 ∼ C 20 aryl group or a C 5 ∼ C 20 heterocyclic group, wherein in case that Ar2 and Ar4 are selected from the following substituents, Ar2 is the same as Ar4; L1 is the same as L2, and L1 and L2 are an unsubstituted phenylene group or an unsubstituted naphthylene group, and Ar1 is the same as Ar3, and Ar1 and Ar3 are an unsubstituted phenyl group or an unsubstituted naphthyl group: