Abstract: Owing to its wide energy band gap, fast ionic conductivity at high temperatures, the ability to maintain a stable p-type conductivity at room temperature and poor spin-orbit splitting, γ-CuI is widely used in optical energy applications and ultrafast scintillation materials. The morphology of γ-CuI is determined by its synthesis conditions. In this paper,γ-CuI with different morphology were synthesized by microreaction method through controlling different NH₃·H₂O dosage, Cu source, in-tube reaction residence time, and temperature in the reaction. The crystalline phase and morphology of these γ-CuI were investigated by SEM, XRD and FT-IR. The γ-CuI prepared by the traditional liquid phase precipitation method was taken as a comparison. The results show that, the highest yield of 90.5% is achieved when the amount of NH₃·H₂O used (C_NH3·H2O/C_N2H4) is 0.4, the residence time in the tube is 10 s, and the reaction temperature is 20 ℃. Among them, the amount of NH₃·H₂O used (which has the greatest effect on the morphology) is 0.4, the rod-shaped γ-CuI with homogeneous morphology is synthesized. Comparing different Cu sources, except for Cu(CH₃COO)₂·H₂O that is prepared to obtain the rod-shaped γ-CuI, all the remaining Cu sources mainly produce the granular γ-CuI. Increasing the in-tube time contribute to the rod-shaped γ-CuI CuI formation, but further increase time will lead to sample loss in the tube. In addition, too high reaction temperature will cause the gradual conversion of rod γ-CuI to granular γ-CuI.

Key words: γ-CuI, N₂H₄·H₂O, microreactor, microfluidic method, microporous sieve plate, morphological control