Light-emitting device and electronic apparatus including same

A light-emitting device comprising:

• a first electrode;
• a second electrode facing the first electrode;
• and
• an emission layer between the first electrode and the second electrode,
• wherein the emission layer comprises:
• i) a first emission layer and ii) a second emission layer between the first emission layer and the second electrode,
• the first emission layer is in direct contact with the second emission layer,
• the first emission layer comprises a first dopant, a first hole-transporting compound, and a first electron-transporting compound,
• the second emission layer comprises a second dopant, a second hole-transporting compound, and a second electron-transporting compound,
• the first dopant is identical to the second dopant,
• the first electron-transporting compound is different from the second electron-transporting compound,
• the first electron-transporting compound is a compound represented by Formula 7S and the second electron-transporting compound is a compound represented by Formula 7F,
• wherein, in Formulae 7S and 7F,
• Ar71 to Ar76 are each independently a benzene group or a carbazole group, each unsubstituted or substituted with deuterium, a C1-C20 alkyl group, a phenyl group, a deuterated phenyl group, a (C1-C20 alkyl)phenyl group, a biphenyl group, a deuterated biphenyl group, a (C1-C20 alkyl) biphenyl group, or any combination thereof,
• a71 to a76 may each independently be 1, 2, or 3,
• R71 to R76 may each independently be hydrogen, deuterium, a C1-C20 alkyl group, a phenyl group, a deuterated phenyl group, a (C1-C20 alkyl)phenyl group, a biphenyl group, a deuterated biphenyl group, a (C1-C20 alkyl) biphenyl group, a carbazolyl group, a deuterated carbazolyl group, a (C1-C20 alkyl) carbazolyl group, a di(C1-C20 alkyl) carbazolyl group, or a (phenyl) carbazolyl group,
• an electron mobility of the second electron-transporting compound is greater than an electron mobility of the first electron-transporting compound, and
• the electron mobility of the first electron-transporting compound and the electron mobility of the second electron-transporting compound are respectively evaluated by using a time versus current graph of a time of flight (TOF) device comprising the first electron-transporting compound or the second electron-transporting compound,
• wherein Equation 4 is satisfied:
• Con(ET2)<Con(ET1) Equation 4
• wherein, in Equation 4,
• Con (ET2) indicates the parts by weight of the second electron-transporting compound, based on 100 parts by weight of the total weight of the second dopant, the second hole-transporting compound, and the second electron-transporting compound, and
• Con (ET1) indicates the parts by weight of the first electron-transporting compound, based on 100 parts by weight of the total weight of the first dopant, the first hole-transporting compound, and the first electron-transporting compound.

A light-emitting device comprising:

• a first electrode;
• a second electrode facing the first electrode;
• and
• an emission layer between the first electrode and the second electrode,
• wherein the emission layer comprises:
• i) a first emission layer and ii) a second emission layer between the first emission layer and the second electrode,
• the first emission layer is in direct contact with the second emission layer,
• the first emission layer comprises a first dopant, a first hole-transporting compound, and a first electron-transporting compound,
• the second emission layer comprises a second dopant, a second hole-transporting compound, and a second electron-transporting compound,
• the first dopant is identical to the second dopant,
• the first electron-transporting compound is different from the second electron-transporting compound,
• the first electron-transporting compound is a compound represented by Formula 7S and the second electron-transporting compound is a compound represented by Formula 7F,
• wherein, in Formulae 7S and 7F,
• Ar71 to Ar76 are each independently a benzene group or a carbazole group, each unsubstituted or substituted with deuterium, a C1-C20 alkyl group, a phenyl group, a deuterated phenyl group, a (C1-C20 alkyl)phenyl group, a biphenyl group, a deuterated biphenyl group, a (C1-C20 alkyl) biphenyl group, or any combination thereof,
• a71 to a76 may each independently be 1, 2, or 3,
• R71 to R76 may each independently be hydrogen, deuterium, a C1-C20 alkyl group, a phenyl group, a deuterated phenyl group, a (C1-C20 alkyl)phenyl group, a biphenyl group, a deuterated biphenyl group, a (C1-C20 alkyl) biphenyl group, a carbazolyl group, a deuterated carbazolyl group, a (C1-C20 alkyl) carbazolyl group, a di(C1-C20 alkyl) carbazolyl group, or a (phenyl) carbazolyl group,
• an electron mobility of the second electron-transporting compound is greater than an electron mobility of the first electron-transporting compound, and
• the electron mobility of the first electron-transporting compound and the electron mobility of the second electron-transporting compound are respectively evaluated by using a time versus current graph of a time of flight (TOF) device comprising the first electron-transporting compound or the second electron-transporting compound, and
• the electron mobility is measured in the time of flight (TOF) device having a 1 um neat film of the respective compound between ITO and aluminum electrodes under a field strength of 2×105 V/cm.