Dual-functional lanthanide ions doped lanthanum titanate microcrystals for simultaneous temperature detection and photothermal conversion

The dual-functional optical materials that can achieve accurate temperature sensing and effective photothermal conversion have aroused great concern in biomedical and industrial fields. However, the lack of optical functional materials limits the photothermal devices in practical applications. In this work, the pure monoclinic Ho 3+ /Yb 3+ codoped La 2 Ti 2 O 7 microcrystals have been successfully synthesized for optical thermometry and photothermal conversion. Different from the partial overlap of thermal coupling energy levels in Er 3+ , the wide separation of emission bands in Ho 3+ reduce the calculation error of ratio-metric thermometry. The maximum value of sensitivity reaches 1.41% K −1 . And the light-to-heat energy conversion of the sample has been explored by some photothermal experiments. It is confirmed that the sample can be heated to the specified temperature by adjusting the power of the heating light source. Meanwhile, the photothermal imaging can be achieved because of the high photothermal conversion of the material. Besides, the dual-functional prototype probe based on La 2 Ti 2 O 7 :Ho 3+ /Yb 3+ microcrystals has been made to investigate the temperature sensing and photothermal conversion performance. These results illustrated the sample has potential applications in optical thermometry and biological photothermal therapy.