Tunable electronic energy transfer between mixed-metal donors and lanthanide acceptors

Ln[M(CN)_2]_3 systems (Ln=trivalent rare earth, M=Au,Ag) have a layered structure consisting of alternating layers of the M(CN)_2- ions and Ln3+ ions. Recent studies of tunable energy transfer in our group have focused on transfer from Au(CN)_2- or Ag(CN)_2- donor ions to a variety of rare earth ions, including Tb3+ and Eu3+. We have recently characterized systems with mixed metal donors, such as La[Ag_.5Au_.5(CN)_2]_3 and La[Ag_.9Au_.1(CN)_2]_3. We have found that these systems exhibit ``tunability'' of emission energy due to the variation of the donor emission associated with varying the Ag/Au ratio. Also, the steady-state luminescence spectra of these compounds reveals that they are strongly luminescent at room temperature, in contrast to the corresponding La[Ag(CN)_2]_3 and La[Au(CN)_2]_3 pure metal systems. Results are presented from studies implementing the mixed-metal systems as donors for energy trasfer.