Spectrally Tunable Lead-Free Perovskite Rb2ZrCl6:Te for Information Encryption and X-ray Imaging

A series of lead-free Rb2ZrCl6:xTe4+(x= 0%, 0.1%, 0.5%, 1.0%, 2.0%, 3.0%, 5.0%, 10.0%) perovskite materials were synthesized through a hydrothermal method in this work. The substitution of Te4+for Zr in Rb2ZrCl6was investigated to examine the effect of Te4+doping on the spectral properties of Rb2ZrCl6and its potential applications. The incorporation of Te4+induced yellow emission of triplet self-trapped emission (STE). Different luminescence wavelengths were regulated by Te4+concentration and excitation wavelength, and under a low concentration of Te4+doping (x≤ 0.1%), different types of host STE emission and Te4+triplet state emission could be achieved through various excitation energies. These luminescent properties made it suitable for applications in information encryption. When Te4+was doped at high concentrations (x≥ 1%), yellow triplet state emission of Te4+predominated, resulting in intense yellow emission, which stemmed from strong exciton binding energy and intense electron-phonon coupling. In addition, a Rb2ZrCl6:2%Te4+@RTV scintillating film was fabricated and a spatial resolution of 3.7 lp/mm was achieved, demonstrating the potential applications of Rb2ZrCl6:xTe4+in nondestructive detection and bioimaging.