Transition temperature reduction for CdS nanoparticles under high pressure

The structure transition of nanoparticles has a significant effect on their practical applications. In this study, the transition temperature of CdS nanoparticles with the size of 3–5 nm from sphalerite to wurtzite structure is significantly reduced to 150 °C under a high pressure of 1 GPa, much lower than that 300–400 °C for CdS nanoparticles and 600 °C for bulk CdS under room pressure. The lower transition temperature leads to an ultrafine grain size d = 5 nm for the formed wurtzite phase as compared with that d = 33 nm yielded under room pressure with a similar transition volume fraction of ~80%. The underlying physical mechanism is discussed.