NaGd(MoO 4 ) 2 :Er 3+ /Tm 3+ Upconversion Phos
Haozhe Gui, Haibin Zhang, Tao Pang, Yuchao Fei, Shisheng Lin, Sitingyu Qiu, Jiayu Wang, Peiyuan Li, Xijian Chen, Mengyao Zhang, Jie Li, Chenyu Wang, Daqin ChenABSTRACT
Lanthanide‐ion‐doped upconversion phosphors for temperature sensing continue to attract considerable fundamental and practical interests. In this work, a NaGd(MoO 4 ) 2 :Er 3+ ,Tm 3+ phosphor, characterized by efficient electron storage at the 3 F 4 (Tm 3+ ) and 4 I 11/2 (Er 3+ ) levels, is designed to reconfigure energy migration pathways under 1550 nm excitation. The results demonstrate that a competitive interplay between backward energy transfer (BET) and forward energy transfer (FET) governs energy migration. The observed upconversion luminescence (UCL) exhibits intense 795 nm near‐infrared emission attributed to the Tm 3+ : 3 H 4 → 3 H 6 transition, which is further significantly enhanced upon heating due to phonon‐assisted energy transfer and thermally induced lattice expansion that facilitate population of the Tm 3+ : 3 H 4 level, leading to a 2.41‐fold enhancement, while the Er 3+ red emission ( 4 F 9/2 → 4 I 15/2 ) undergoes conventional thermal quenching. Leveraging these contrasting thermal quenching behaviors and a high‐thermal‐conductivity phosphor‐on‐ceramic architecture, reliable UCL‐based temperature sensing is demonstrated. This study highlights the controllable nature of excitation energy migration in Er 3+ /Tm 3+ co‐doped systems and provides valuable design principles for high‐performance upconversion thermometry.