Increased luminescent lifetimes of Ln(3+) complexes emitting in the near-infrared as a result of deuteration

The luminescence of lanthanide(III) ions emitting in the near-infrared regi on is ideally suited for telecommunications applications, and a number of a pplications have been developed. These are in general based on inorganic ma trices, but polymer-based matrices would have advantages in device fabricat ion. In organic matrices, however, molecular vibrations in the matrix quenc h the excited state of luminescent lanthanide ions. Replacement of strongly quenching groups such as C-H oscillators by more weakly quenching groups e nhances the luminescence lifetime and hence also the luminescence quantum y ield. This article reports a synthesis route developed in order to deuterat e all C-H groups that contribute to the quenching in an organic lanthanide complex. The luminescences of three near-infrared emitting lanthanide ions - Nd3+, Er3+, and Yb3+ - were measured. The maximum effect achieved upon de uteration is a factor of 2-3, but lifetimes remain in the microsecond regio n (1-Nd3+: 5.5 mus; 1-Yb3+: 52.3 mus; 1(.)Er(3+): 5.4 mus).