Highly sensitive response of luminescence chromaticity to laser power in Lu 2 Mo 4 O 15 :Yb 3+ /Ho 3+ 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 Ho 3+ -based PUCR. Herein, favorable PUCR behavior is achieved by codoping Yb 3+ and Ho 3+ into the Lu 2 Mo 4 O 15 lattice. It has been demonstrated that the ultrashort lifetime of the Ho 3+ : 5 I 6 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 Er 2 Mo 4 O 15 :4% Tm 3+ we recently reported that Lu 2 Mo 4 O 15 :90% Yb 3+ /1% Ho 3+ , thanks to the high solubility of Yb 3+ ions, showed a ∼25-fold enhancement in emission intensity. This new material is potentially applicable in dynamic luminescence anti-counterfeiting.