Color manipulation of mechanoluminescence and photoluminescence from CaZnOS:ZnS:Mn2+ heterocompound controlled by ion doping concentration

Calcium zinc oxysulfide (CaZnOS) and cognate semiconductors are emerging materials possessing exceptional piezoluminescent properties. A CaZnOS:ZnS binary heterocompound doped with various Mn2+ concentrations from 0.1 to 8% has been prepared using the solid-state reaction method. The structural, chemical and optical properties of the obtained powders are studied. Their crystal structure and compositional analyses have shown two stable main phases of ZnS and CaZnOS so that the powder generally appears as a binary compound of the ZnS:Mn2+ and CaZnOS:Mn2+ particles. The role of ZnS:Mn2+ and CaZnOS:Mn2+ phases on mechanoluminescence (ML) and photoluminescence (PL) is particularly investigated. The luminescence spectra show the contribution of ZnS:Mn2+ and CaZnOS:Mn2+ as particles of yellow and red colors, respectively. When increasing the Mn2+ concentration, a redshift of the luminescence spectra and optical bandgap is observed due to a rising contribution of the CaZnOS:Mn2+ phase. By this means, a bright luminescence along with color manipulation from yellow to red is achieved. So, by capturing long-exposure photographs of ML from the powder in a flexible film, the powder samples are used to write a pattern. The brightest emission is observed up to 0.8% of Mn2+, while the luminescence gradually lowers at higher dopant concentrations. The experimental base shows that a binary compound containing highly efficient novel CaZnOS and conventional ZnS doped with Mn2+ ions is a proper way to develop intense multicolor ML ranging from yellow to red emission.