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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 Rb2ZrCl6 was investigated to examine the effect of Te4+ doping on the spectral properties of Rb2ZrCl6 and 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. [ABSTRACT FROM AUTHOR]

Carbon nitrides form a series of polymer semiconductors popular in photocatalysis. In the course of photoresponse, the separation of light-induced electron–hole pairs is one of the critical factors that affect the conversion rate from photoenergy to chemical substance. Exciton binding energy ( E b ) is treated as a classical parameter to evaluate the barrier of exciton dissociation. In this work, we study the electronic and optical nature of two specific members of the carbon nitride family, polymeric carbon nitride (melon) and crystallized poly(triazine imide) (PTI/Li+Cl−) by employing the photoluminescence spectra and density functional theory (DFT) calculations based on the Wannier-Mott exciton module. The results of self-consistent GW computation were applied. The measurement of photoluminescence spectra, by which exciton binding energies are estimated, is likewise discussed. Generally, compared with the results calculated by GW-BSE, the DFT results based on the Wannier-Mott model are closer to the experimental values. From a materials perspective, on the other hand, the exciton binding energy of the melon is lower than that of PTI/Li+Cl−. [ABSTRACT FROM AUTHOR]