Colloidal synthesis of homogeneously alloyed $In_{1-x}Ga_xP$ quantum dots

Abstract

InP quantum dots (QDs) are attracting attention as a significant material for next-generation display’s light emitting materials due to the low intrinsic toxicity, high optical efficiency, and color purity. However, due to the limitation of size, it is difficult to implement deep-blue and there is a large lattice mismatch with the shell material as Zn-chalcogenide, so it is required to synthesize alloy composition quantum dots with GaP having a larger lattice parameter and bandgap compared to InP. In this paper, $In_{1-x}Ga_xP$ (0 < x < 1) QDs were synthesized with In3+-to-Ga3+ cation exchange, and uniformly alloyed $In_{1-x}Ga_xP$ QDs were synthesized through annealing at high temperatures (> 400 °C). The synthesized InP QDs and GaI3 were heated to 320 °C to induce cation exchange, and it was confirmed that the contents of Ga in the QDs increased according to the temperature and the injection amount of GaI3. It was observed that the blue shift of the absorption wavelength and the radial element composition became constant through the heat treatment of the $In_{1-x}Ga_xP$ QDs. This homogeneous alloying strategy of $In_{1-x}Ga_xP$ QDs is meaningful in that it has been shown that uniform alloying of group III-V based QDs are possible on colloidal phase.