Integration of green CuInS_2/ZnS quantum dots for high-efficiency light-emitting diodes and high-responsivity photodetectors

Ternary I–III–VI quantum dots (QDs) have been regarded as an alternative to Cd- and Pb-based QDs because of their appealing optoelectronic properties and their deficiency in highly toxic components. In this paper, we present the synthesis of highly luminous and emission-tunable CuInS2/ZnS core/shell QDs and their application to the fabrication of highly efficient electroluminescent QD light-emitting diodes (QLEDs). To evaluate the possibility of applying CuInS2/ZnS QDs to photodetectors (PDs), the CuInS2/ZnS-graphene hybrid PDs with a high-responsivity were successfully constructed for the first time. In this study, QLEDs based on the as-prepared CuInS2/ZnS core/shell QDs exhibited a high external quantum efficiency of 3.36% at a forward current of 2.8 V, which is higher than that of CuInS2-based electroluminescent QLEDs reported previously. The resulting PD exhibited a surprisingly high responsivity of 35 A/W. CuInS2/ZnS QDs provide new opportunities for the fabrication of non-toxic QLEDs and PDs exhibiting high performances and are promising for future applications in the field of optoelectronic devices.