Synthesis and study of single crystals and optical ceramics based on the AgCl0.25Br0.75-AgI system

To obtain non-toxic, non-hygroscopic materials used in IR fiber optics and optoelectronics, a comprehensive study of the AgCl0.25Br0.75 - AgI system was carried out. The study of the AgCl0.25Br0.75 - AgI system's phase diagram showed the presence of a homogeneity region with a content 0-16 mol.% AgI in AgCl0.25Br0.75 and heterogeneity region 16-98 mol.% AgI in AgCl0.25Br0.75. The phases in the homogeneous region have a cubic structure of the Fm3m type. The phases in the heterogeneous region are a mixture of cubic Fm3m and hexagonal P63mc phases. Within each of the regions, single-crystals samples with compositions of 4, 8, 16, and 20 mol.% AgI in AgCl0.25Br0.75 and optical ceramics ones of composition 20 and 33 mol.% AgI in AgCl0.25Br0.75 were synthesized. For a sample of 20 mol.% AgI in AgCl0.25Br0.75, different synthesis modes were used, as a result it was possible to obtain both a single-crystal and ceramics. The materials' band gap and the optical transmission range are determined. The band gap decreases from 2.5195 to 2.3724 with a rise in the fraction of AgI in AgCl0.25Br0.75. The materials are transparent in the range of 0.492 -54 & mu;m. Single-crystals are characterized by a stepwise increase in transmission up to 50-57% at the short-wavelength absorption edge. For optical ceramics, the transmission initially reaches 1% stepwise and then increases until reaching a maximum value in the IR of 15-20 & mu;m. It is associated with scattering by grains of different phases. A uniform shift of the transmission spectrum to longer wavelengths from 492 to 525 nm in the visible and from 47 to 54 & mu;m in the far IR with a rise in the proportion of AgI in AgCl0.25Br0.75 is shown. The single-crystals' and optical ceramics' highest transmission level reaches 75-78% in the wavelength range from 10 to 40 & mu;m.

Automated summary

A comprehensive study was conducted on the AgCl0.25Br0.75 - AgI system to obtain non-toxic, non-hygroscopic materials for IR fiber optics and optoelectronics. The study revealed a homogeneity region with 0-16 mol.% AgI in AgCl0.25Br0.75 and a heterogeneity region with 16-98 mol.% AgI in AgCl0.25Br0.75 in the phase diagram. The materials synthesized within these regions showed variations in band gap, optical transmission range, and scattering properties.