(662f) Synthesis of Metal Phosphide Nanocrystals for Optoelectronics

Our growing energy usage, stressed by the apparent effects of climate change, has created an urgent need for sustainable sources of lighting and electricity. Successful development of such technology relies on our discovery of scalable photonic materials that can compete with current traditional group IV (Si, Ge) and III-V (GaN, GaAs) semiconductors, but have low toxicity and processing costs. Comprising of abundant, non-toxic, recyclable elements, nanoscale metal phosphide systems have garnered interest for such applications. To date, however, development of nanoscale metal phosphides has been deterred because of issues like the toxicity of metal and phosphorus precursors, poor stability under atmospheric conditions, and low quantum yield. In this work, we present reliable colloidal routes to group II and group IV phosphide (II – Zn, IV – Sn, Ge) nanocrystals from various metal and phosphorus precursors, some environmentally benign. We present optimization of synthesis protocols to allow for tunability of nanocrystal size and size dispersity. Structure and optoelectronic property relationships are explored via x-ray diffraction, transmission electron microscopy, and x-ray absorption spectroscopy. Finally, we show preliminary results on implementation of these materials in functional devices.