Proposed schedule for the use of SiNWs as colorimetric sensors based on their structural properties. M and E represent the magnetic and electric fields, respectively. 

The detection of anions in pure water phase with colorimetric sensor is a long standing challenge. As one of the most important anions, F– is associated with nerve gases and the refinement of uranium for nuclear weapons. However, limited by its anions nature, few of the reported colorimetric sensors can successfully applied to detect F–1 in pure water phase. This work designs a colorimetric sensor for F–1 pure water phase detection by taking the advantages of the strong specific binding between F and Si, as well as the color-changing property of H-terminated Si nanowires (SiNWs). The sensor demonstrates ultra-sensitivity, high selectivity, and good stability. The results reveal particular interest for the development of new type aqueous phase anions sensors with SiNWs.

Advanced Functional Materials, Volume 25, Issue 10, pages 1506–1510, March 11, 2015