Encapsulation of zinc oxide nanorods and nanoparticles

A simple method for encapsulating zinc oxide nanoparticles within an organic matrix is described that consists of dispersing them in an ethanolic solution, adding an organothiol, and stirring while heating. Electron microscopy, photoemission, Raman spectroscopy, and thermal gravimetric analyses demonstrate that partial dissolution of the oxide occurs, accompanied by encapsulation within a matrix consisting of a 1:2 zinc/thiol complex. Using this methodology, it is possible to surround ZnO within diverse matrices, including fluorescent ones. The process is demonstrated for 1-dodecanethiol (DDT) and fluorescent 2-naphthalenethiol (NPT). For DDT, ZnO nanorods become surrounded by a layer of the zinc-thiol complex that is greater than 100 A thick. In the case of NPT, significantly greater dissolution of the ZnO occurs, with the encapsulated rods taking on a spherical geometry, as evidenced by electron microscopy.