Hydrothermal synthesis and properties of a red-emitting phosphor of fully concentrated Eu 3+ based oxalate Eu 2 (C 2 O 4 ) 3 ·10H 2 O

Abstract Fully concentrated Eu 3+ based oxalate Eu 2 (C 2 O 4 ) 3 ·10H 2 O phosphor has been successfully synthesized by an efficient surfactant-free hydrothermal method directly without further sintering treatment. The techniques of XRD, TG–DTA, FT-IR, SEM, EDS and PL were employed to characterize the as-obtained products. It was found that in the temperature range of 100–150 °C, all samples were well crystallized with monoclinic structures. And the best purity of the samples produced was achieved when the temperature is 150 °C. The possible formation mechanisms for Eu 2 (C 2 O 4 ) 3 ·10H 2 O with different structures were put forward. The Eu 2 (C 2 O 4 ) 3 ·10H 2 O phosphors can be effectively excited by 396 nm light, and exhibit strong red emission around 619 nm, attributed to the Eu 3+ 5 D 0 → 7 F 2 transition. A detailed investigation on the fluorescence of products revealed that the luminescence properties are strongly correlated with the crystallinities, morphologies and sizes.