Luminescent thermochromic materials with a dramatic shift of emission band under different temperatures are highly desirable in temperature sensing fields. However, the design of the synthesis of such compounds remains a great challenge. In this work, two new luminescent thermochromic silver iodides, (emIm)­Ag3I4 (1) and (emIm)­Ag2I3 (2) (emIm = 1-ethyl-3-methyl imidazole), have been synthesized under solvothermal conditions. Compound 1 features a [Ag3I4]− anionic layer, while compound 2 possesses an infinite [Ag2I3]− chain structure, both of which are charge balanced by emIm+ cations. Particularly, they display luminescent thermochromism with a significant wavelength shift of emission maximum with temperature change. They represent rare examples of infinite layered or chain silver iodides that show luminescent thermochromism. Furthermore, the results indicate that compounds 1 and 2 are promising wavelength-dependent luminescent thermometers.

Cluster-based framework metal iodides have diverse structures and excellent luminescence properties, and show promising applications in sensing and solid-state lighting. However, the design and synthesis of these materials remain great challenges because excess I– ions introduced into the synthesis systems decrease the condensation degree of M–I units. In this work, a new strategy is developed to control the condensation behavior of Ag–I units, and a new silver-rich cluster-based framework iodide [DabcoAg8I6(SPh)2] n (1) (Dabco = 1,4-diazabicyclo [2.2.2] octane) has been synthesized under solvothermal conditions in the presence of silver thiophenolate (AgSPh) n . Compound 1 features a three-dimensional (3-D) cluster-based framework with a pillared layer structure composed of cationic [Ag8I6]2+ clusters bridged by SPh– and Dabco, and displays low-temperature dual emission and luminescence thermochromism.

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