Tetraphenylethylene-based blue light-emitting organic salt crystals†

In recent years, tetraphenylethylene (TPE)—a representative organic molecule with excellent structural tunability and luminescence properties—has attracted considerable attention for application in optoelectronic materials. In this study, we synthesised four organic salt crystals via the combination of a TPE-based organic cation (3-pyridyl-tetraphenylethylene, T3Py–TPE⁴⁺) with di- or tetra-anionic aromatic sulfonate anion ligands [BPDS = (1,1′-biphenyl)-4,4′-disulfonate, 1,5-NDS = naphthalene-1,5-disulfonate, TPMS = 4,4′,4′′,4′′′-methanetetrayltetrabenzenesulfonate and TPADS = 4,4′,4′′,4′′′-(adamantane-1,3,5,7-tetrayl)tetrabenzenesulfonate] using a simple one-pot method. The different conformations of the cation in the crystals caused significant blue-shifted emission, with quantum yields as high as 97%. Importantly, this work presents a method for designing and constructing functionalised organic salt materials by controlling the ionic interactions.