Bi-dipole emission via plasmon modes of Au/Ag nanoshell

► The radiative and nonradiative powers of bi-dipoles interacting with Au/Ag NS at the plasmon modes are analyzed. ► The Purcell factors of NS on the emission of bi-dipoles are increased dramatically at the dipole and quadrupole modes. ► The plasmon modes are tunable by adjusting the percentage of Au. ► The dipole mode is a bright mode, while the quadrupole mode is a dark one.