Solution‐State Cooperative Luminescence Upconversion in Molecular Ytterbium Dimers (Advanced Optical Materials 11/2023)

Two heterometallic ytterbium dimers exhibit molecular cooperative luminescence (CL) in solution. Excitation into the Yb absorption band at 980 nm induces emission at ≈510 nm through a two-photon process. The work by Loïc J. Charbonnière and co-workers (article number 2202307) demonstrates a miniaturization of the CL phenomenon down to its mechanistically simplest form of only two Yb ions through formation of a Yb2** doubly excited state.