Compressibility of zinc sulfide nanoparticles

We describe a high-pressure x-ray diffraction (XRD) study of the compressibility of several samples of ZnS nanoparticles. The nanoparticles were synthesized with a range of sizes and surface chemical treatments in order to identify the factors that determine nanoparticle compressibility. Refinement of the XRD data revealed that all ZnS nanoparticles in the nominally cubic (sphalerite) phase exhibited a previously unobserved structural distortion under ambient conditions that exhibited, in addition, a dependence on pressure. Our results show that the compressibility of ZnS nanoparticles increases substantially as the particle size decreases, and we propose an interpretation based upon the available mechanisms of structural compliance in nanoscale vs bulk materials.