| abstract |
A phosphorescent-emitting layer (51, 52) contains a phosphorescent host and a phosphorescent dopant for providing phosphorescence, and a fluorescent-emitting layer (7) contains a fluorescent host and a fluorescent dopant for providing fluorescence. A charge blocking layer (6) blocks electrons injected into the fluorescent host of the fluorescent-emitting layer (7) from being injected toward the charge blocking layer (6) from the fluorescent-emitting layer (7), and also injects holes into the fluorescent-emitting layer (7) from the phosphorescent-emitting layer (51, 52). A triplet energy gap Eg PD of the phosphorescent dopant of the phosphorescent-emitting layer (51, 52), a triplet energy gap Eg EB of the charge blocking layer (6) and a triplet energy gap Eg FH of the fluorescent host of the fluorescent-emitting layer (7) satisfy the following formula (1). Eg PD < EgEB ¤ Eg FH |