“…Discussion is found in the literature regarding the luminescence of copper-doped glasses with respect to whether single copper ions or copper dimers or clusters are responsible for the emission. 15,20,31,33,36–40 The extent to which molecule-like copper clusters manifest depends on various factors such as the host structural properties, metal solubility, dopant concentration, and glass thermal history. The present melt-quenched CuO/SnO-containing phosphate glass has been characterized by high metal solubility 21 likely enhanced by the metalophilic agent tin, 41 which has been indicated to impact the PL properties.…”