Patent ID: 8274074

Claim:
A polymer material comprising a composition containing a fluorescent conjugated polymer (A) and a phosphorescent compound (B) or comprising a polymer having the structure of (A) and the structure of (B) in the same molecule, wherein the following conditions (1), (2) and (3) are satisfied: (1) at least one of the light emission peak wavelengths of the fluorescent conjugated polymer (A) is less than 500 nm, (2) the light emission peak wavelengths of the phosphorescent compound (B) are not less than 500 nm, (3) the following relation is satisfied: ET A −ES A 0 ≧( ET B −ES B )−0.2 (unit; eV) (Eq 1) (wherein, ES A 0 represents energy of the fluorescent conjugated polymer (A) at the ground state, ET A represents energy of the fluorescent conjugated polymer (A) at the lowest excited triplet state, ES B 0 represents energy of the phosphorescent compound (B) at the ground state, and ET B represents energy of the phosphorescent compound (B) at the lowest excited triplet state).