Eu- and Tb-adsorbed Si3N4 and Ge3N4: Tuning the colours with one luminescent host

Phosphor-converted white light-emitting diodes (pc-LEDs) are emerging as an indispensable solid-state light source for the next generation lighting industry and display systems due to their unique properties. Nitrides with their wide-ranging applicability due to their intriguing structural diversity, their auspicious chemical and physical properties represent an essential component in industrial and materials applications. Here, we present the successful adsorption of Eu and Tb at the grain boundaries of bulk β-Si3N4 and β-Ge3N4 by a succeeding combustion synthesis. The adsorption of europium and terbium and the synergic combination of both resulted in intriguing luminescence properties of all compounds (red, green, orange and yellow). Especially the fact that one host can deliver different colours renders Eu,Tb-β-M3N4 (M= Si, Ge) as prospective chief components for future light emitting diodes (LEDs). For the elucidation of the RE adsorption on the electronic properties of β-Si3N4 and β-Ge3N4, Mott-Schottky (MS) measurements were conducted for the bare and RE adsorbed samples. Further insight on the electronic structure of β-Si3N4 and β-Ge3N4 were obtained via density functional theory (DFT) computations.