Multi-Emitting Ratiometric Temperature Sensing and Tunable White Light Emitting Based on Effective Energy Transfer in a Lanthanide-Brønsted Acidic Ionic Liquid Coordination Polymer

Isostructured lanthanide-Brønsted acidic ionic liquid coordination polymers, {[Ln(C 7 H 7 N 2 O 4 )(H 2 O) 4 ]Cl 2 } n (LnIMDC(H 2 O) 4, Ln = Eu 3+, Gd 3+, or Tb 3+, C 7 H 7 N 2 O 4 = [IMDC] − ) and {[Eu 0.5 Tb 0.5 (C 7 H 7 N 2 O 4 )(H 2 O) 4 ]Cl 2 } n (Eu 0.5 Tb 0.5 IMDC(H 2 O) 4 )), have been synthesized using 1,3-bis(carboxymethyl) imidazolium chloride ([H 2 IMDC]Cl) as linkers. LnIMDC(H 2 O) 4 (Ln = Eu 3+ or Tb 3+ ) and Eu 0.5 Tb 0.5 IMDC(H 2 O) 4 exhibit good temperature sensing performance over a wide temperature range with maximum sensitivities S r of 2.73%·K –1 (392 K) and 2.74%·K –1 (362 K), and 2.21% K –1 (383 K), respectively. Meanwhile, the white light emission of Eu 0.5 Tb 0.5 IMDC(H 2 O) 4 was achieved with Commission Internationale de l’Eclairage coordinates of (0.323, 0.328), a correlated color temperature of 5942 K, and a color rendering index (CRI) of 90. Moreover, the temperature response of the as-synthesized Eu 0.5 Tb 0.5 IMDC(H 2 O) 4 @PDMS film was monitored. The energy transfer efficiency and phosphorescence lifetime in the abovementioned coordination polymers were investigated to explore the energy transfer efficiency between [IMDC] − and Ln 3+ as well as between Tb 3+ and Eu 3+ .