On the basis of such analyses, A1 and A2 parameters were further compared among CIS, Cd–CIS, and Zn– CIS NCs. As shown in Table 3, A1 and A2 parameters are decreased for both 0.2 Cd–CIS and 0.5 Cd–CIS compared to those of CIS. This indicates that Cd alloying may reduce surface or intrinsic defects of NCs. This observation could explain why the QYs of Cd–CIS increase to 12–14 % compared to those of CIS (*7 %). For 0.2 Zn–CIS and 0.5 Zn–CIS, A1 parameters increase to 6 and 11 % and A2 parameters increase to 28 and 33 %, respectively. This suggests that the Zn alloying increases surface or intrinsic defects, resulting in the low QYs of Zn–CIS. Moreover, more Zn alloyed in CIS causes more defects and thus a lower QY. An increased number of defects in