The green photoluminescence emission from terbium rare earth ions embedded in the wide band gap matrices wurtzite AlN and amorphous SiC shows the same functional rapid decay with increasing concentration (concentration quenching). Thus this decay is insensitive against both the structural and the chemical nature of the matrix. A rate equation model can describe this quenching process. Special attention is paid to the adequate averaging procedures. © 2012 Elsevier B.V.