Highly sensitive response of luminescence chromaticity to laser power in Lu2Mo4O15:Yb3+/Ho3+ upconverting materials

Power-based upconversion luminescence color regulation (PUCR) is especially suitable for developing dynamic luminescence anti-counterfeiting owing to its straightforward usage. However, it remains a challenge to achieve visually remarkable Ho3+-based PUCR. Herein, favorable PUCR behavior is achieved by codoping Yb3+ and Ho3+ into the Lu2Mo4O15 lattice. It has been demonstrated that the ultrashort lifetime of the Ho3+:5I6 level and the anomalous three-photon nature of green emission are essential. The former causes high-purity red emission at low power, while the latter enables power-responsive tuning from red to green. Compared with Er2Mo4O15:4% Tm3+ we recently reported that Lu2Mo4O15:90% Yb3+/1% Ho3+, thanks to the high solubility of Yb3+ ions, showed a ∼25-fold enhancement in emission intensity. This new material is potentially applicable in dynamic luminescence anti-counterfeiting.