Investigation on tunable red and white emissions in Bi3+/Eu3+ co-doped Y2Zr2O7 microcrystals

In this study, we synthesized Y2Zr2O7 (YZO): Bi3+/Eu3+ microcrystals through high-temperature solid-phase method. When the microcrystals were excited upon 263 nm and 329 nm, a tunable emission color variation from red to white is observed. The Correlated Color Temperature (CCT) of YZO: 6% mol Bi3+, 5% mol Eu3+ excited upon 329 nm is 4194 K, exhibited warm white light. Furthermore, the emission intensity of Eu3+ ion is remarkably improved by the incorporation of Bi3+ ion, due to the energy transfer from Bi3+ ion to Eu3+ ion. Their efficiency (ηT) in YZO: 6% mol Bi3+, 5% mol Eu3+ reaches 49.17%. The corresponding absolute quantum efficiency (λex = 329 nm) of YZO: 6% mol Bi3+, 5% mol Eu3+ is 56.21%. These results indicate that YZO: Bi3+/Eu3+ microcrystals are highly potential to enhance the industrial growth of photonics field, particularly the application of anti-counterfeiting and white light-emitting diodes.