Synthesis, structures, and optical properties of cadmium iodide/phenethylamine hybrid materials with controlled structures and emissions.

A new type of organic-inorganic hybrid materials based on cadmium iodide (CdI2) and phenethylamine (PEA) has been synthesized and characterized. The reaction of CdI2 with PEA in a 1:2 molar ratio yields a four-coordinate hybrid material CdI2(PEA)2 (1) with extended 1D (CdI2)n chains, while the reaction of CdI2 with PEA in a 1:4 molar ratio produces a six-coordinate hybrid material CdI2(PEA)4 (2) with a discrete linear structure of CdI2 moiety. By introducing a trace amount of Na2S to the reaction for CdI2(PEA)2, we obtained a new compound [CdI2(PEA)2](CdS)0.038 (3) with uniformly doped CdS nanoparticles. Steady and transient photoluminescence studies reveal that compounds 1 and 2 exhibit bright blue (465 nm) and green (512 nm) fluorescent emissions in solid state at room temperature, respectively, while compound 3 gives a broad and complex emission ranging from 450 to 700 nm. Theoretical studies of electronic structures were carried out using density functional theory in order to gain a good understanding of the luminescent behaviors of these hybrid materials.