Mechanical force induced luminescence ratiometric thermometry in CaZnOS:Dy³

The ⁴I_15/2-⁶H_15/2 and ⁴F_9/2-⁶H_15/2 transitions of Dy³⁺ are usually used for luminescent ratiometric thermometry in the form of photoluminescence. However, here we demonstrate the possibility of using this pair of lines for luminescent ratiometric thermometry in the model of mechanoluminescence (ML) in CaZnOS:Dy³⁺. Upon stimulation of an external mechanical force rather than light, CaZnOS:Dy³⁺ emits bright yellow luminescence. The intensity ratio of ⁴I_15/2-⁶H_15/2 to ⁴F_9/2-⁶H_15/2 transitions of Dy³⁺ is found to increase gradually with the rise of temperature, which makes Dy³⁺ a qualified temperature indicator. Our work enriches the family of optical thermometry.