Tunable blue–white–red photoluminescence and long lasting phosphorescence properties of a novel zirconate phosphor: La2Zr2O7:Sm3+,Ti4+

• A novel long lasting phosphorescence phosphor La2Zr2O7:Sm3+,Ti4+ is obtained.
• It shows tunable long lasting phosphorescence (blue, red even white color).
• Important role of Sm3+/Ti4+ as aliovalent auxiliaries to create traps is revealed.
• Energy transfer between Ti4+ and Sm3+ is observed and investigated.

A novel long lasting phosphorescence phosphor La2Zr2O7:Sm3+,Ti4+ is firstly synthesized by solid state method at 1673 K in air. The emission spectrum of La2Zr2O7:Sm3+,Ti4+ consists of a broad band at 460 nm due to charge transfer of O2−–Ti4+ and the emission lines of Sm3+ in 550–700 nm. By changing the co-doping content of Sm3+, the color of photoluminescence and long lasting phosphorescence are tunable and the blue, red even white color can be observed. The spectral overlap reveals the presence of efficient energy transfer between Ti4+ and Sm3+. The long lasting phosphorescence of the optimal sample can be recorded for about 540s(0.32mcd/m2) and the decay curve can not be exponentially fitted for the presence of two decay origins. It reveals that the Sm3+ and Ti4+ ions act as not only emission centers but also aliovalent auxiliaries to create proper shallow traps clusters. Additionally, the deep traps (342 K and 411 K) are proved to be stable enough that the La2Zr2O7:Sm3+,Ti4+ material shows potential applications as not only a long lasting phosphorescence phosphor but also an optical storage material.