In spite of the progress on alloyed CIS NCs, several challenges remain. Few studies have reported how Zn within CIS NCs affects luminescence quantum yields (QYs) while tuning band gaps. Moreover, most reported synthetic approaches for Zn–CIS NCs also adopt hot injection processes which are challenging for large-scale production. The reported Cd–CIS NCs
were synthesized using a solvothermal process and no luminescence properties have been described, which
may indicate excess intrinsic or surface defects causing quenching of luminescence. Excessive defects as trap states in Cd–CIS NCs could limit their applications in photovoltaic devices by means of carrier recombination. It is of interest to develop high quality Cd–CIS NCs with luminescence (or fewer defects) and further examine the role of Cd in NC luminescence wavelength tuning and QY.