Organic electroluminescent device

An organic electroluminescence device comprising an anode, an emitting layer, an electron-transporting region and a cathode in sequential order, wherein

• the emitting layer contains a host and a fluorescent dopant;
• the affinity Ad of the dopant is equal to or larger than the affinity Ah of the host;
• the triplet energy ETd of the dopant is larger than the triplet energy ETh of the host;
• a blocking layer is provided in the electron-transporting region such that it is adjacent to the emitting layer, and the triplet energy ETb of a material constituting the blocking layer is larger than ETh;
• and
• at an applied voltage which makes current efficiency (unit:
• cd/A) maximum, a luminous intensity derived from singlet excitons generated by collision of triplet excitons generated in the emitting layer is 30% or more of the total luminous intensity.