Bulk assemblies of organic antimony chloride with multiple reversible photoluminescence switching for anti-counterfeiting and information encryption

Abstract

Forgery and leakage of confidential information will bring great social harm and economic loss, so it is necessary to take simple and effective strategies to ensure information security. Here, two different zero-dimensional (0D) organic antimony chlorides of [Ph3S]2SbCl5·2C2H3N (1) and [Ph3S]2SbCl5 (2) were obtained by inserting the organic ligand of Ph3SCl (triphenylsulfonium chloride) into SbCl3 lattice via different chemical synthesis methods. Under photoexcitation, compound 1 shines bright yellow emission with a photoluminescence quantum efficiency (PLQE) of 98.2%, while compound 2 shows efficient red emission with a PLQE of 99.6%. Both of them exhibit dual-emission bands, which stem from the singlet self-trapped excitons (STEs) and triplet STEs, respectively. Particularly, the dynamic transformation processes between compounds 1 and 2 are witnessed via the acetonitrile (C2H3N) stripping/insertion under different external stimuli, which was demonstrated by the results of powder X-ray diffraction and photoluminescence (PL) spectra. In addition, the continuous heating of compound 2 can make the emission color change from red to yellow again, accompanied by the lattice distortion of [SbCl5]2- pyramid. Finally, the multiple anti-counterfeiting and information encryption models were fabricated based on the reversible PL switching of the title compounds under different external stimuli.