Er $^{3+}$ -Tm $^{3+}$ -Yb $^{3+}$ :Gd2O3 Upconverting Phosphors for Sensing and Laser-Induced Heating Applications

This paper explores the near infrared (NIR) to visible frequency upconversion emissions in the Er
³⁺
-Tm
³⁺
-Yb
³⁺
tri-doped Gd
₂
O
₃
phosphors prepared by the combustion technique. The cubic phase formation and crystalline structure of the prepared materials has been examined with the help of X-ray diffraction study. The multicolour upconversion emission capability of the prepared materials has been confirmed under the excitation with 980-nm NIR laser source. The relative intensity variation corresponding to the transitions from the thermally coupled energy levels (
²
H
_11/2
,
⁴
S
_3/2
) to the ground level (
⁴
I
_15/2
) of Er
³⁺
ions with pump power and temperature has been studied to investigate the optical temperature sensing ability of the prepared material. The maximum sensor sensitivity of the synthesized material reaches the value 0.0073 K
^-1
at 443 K. The laser-induced heating capacity of the prepared material caused by laser excitation at different pump powers has been analyzed. The observed results support the utility of the prepared materials in optical temperature sensing and laser-induced heating along with additional capability for being used in making NIR to visible upconverter.