Mo6 cluster-based compounds for energy conversion applications: comparative study of photoluminescence and cathodoluminescence

We report the photoluminescence (PL) and cathodoluminescence (CL) properties of face-capped [Mo₆Xⁱ₈L^a₆]^2- (X = Cl, Br, I; L = organic or inorganic ligands) cluster units. We show that the emission of Mo₆ metal atom clusters depends not only on the nature of X and L ligands bound to the cluster and counter-cations, but also on the excitation source. Seven members of the A_xMo₆Xⁱ₈L^a₆ series (A = Cs⁺, (n-C₄H₉)₄N⁺, NH₄⁺) were selected to evaluate the influence of counter-cations and ligands on de-excitation mechanisms responsible for multicomponent emission of cluster units. This study evaluates the ageing of each member of the series, which is crucial for further energy conversion applications (photovoltaic, lighting, water splitting, etc.).