| 摘要 |
PROBLEM TO BE SOLVED: To provide a light emitting device effectively usable for a full-color display, a backlight, a surface light source such as an illumination light source, a light source array of a printer or the like, and having excellent durability, high luminous efficiency and high emission luminance. SOLUTION: This light emitting device has at least one luminescent layer between a pair of electrodes; the luminescent layer includes a positive hole transportation material, an electron transporting material and a luminescent material; and a relationship of Ip(L)≤Ip(HL)≤Ip(EL) is satisfied among their respective ionization potentials Ip(HL), Ip(EL) and Ip(L). In the light emitting device, a relationship of Ip(HH)≤Ip(HL)≤Ip(EL)<Ip(EE) is satisfied among the respective ionization potentials Ip(HH), Ip(HL), Ip(EL) and Ip(EE) of the positive hole transportation material in a positive hole transportation layer, the positive hole transportation material in the luminescent layer, the electron transportation material in the luminescent layer, and the electron transportation material in an electron transportation layer. COPYRIGHT: (C)2005,JPO&NCIPI |
