Synthesis of water-soluble photoluminescent germanium nanocrystals

Photoluminescent germanium nanocrystals were synthesized in solution using hydride reducing agents. The surface of the Ge nanocrystals was modified with allylamine to produce water-soluble photoluminescent Ge nanocrystals. When the reducing agent was added slowly, the particles were 5 nm in size with a narrow size distribution. However, when the reducing agent was injected rapidly, the Ge nanocrystals formed large (50 nm) triangles that were too large to exhibit the effects of quantum confinement and thus did not fluoresce. Characterization of the Ge nanocrystals is performed using transmission electron microscopy, selected-area electron diffraction, energy-dispersive x-ray spectroscopy and optical spectroscopy.