Synthesis of light-coloured nanoparticles of wide band gap p-type semiconductors CuGaO_2 and LaOCuS by low temperature hydro/solvothermal processes

摘要

We report here two original low temperature routes for the synthesis of nanostructured particles of p-type TCOss CuGaO_2 and LaOCuS. Light grey CuGaO_2 nanolayered particles (~300 nm large and 5 nm thick) were prepared from a hydrothermal synthetic route using soluble hydrated metal nitrates as precursors and ethylene glycol (EG) as reducing agent. We found then that the initial pH of the precursor's solution is a key parameter to tune the particle sizes (from 2 μm to 300 nm) and subsequently the colour (from dark brown to light grey) of the CuGaO_2 powder. LaOCuS was obtained for the first time as greyish nanolayered particles (~100nm large and 10 nm thick) via a solvothermal route in ethylene diamine with hydrate chloride lanthanum, copper mono oxide and elemental sulphur as precursors. We found that the control of the chloride lanthanum precursor hydration rate is of prime importance to achieve pure material and to tune the colour of the LaOCuS sample. Both CuGaO_2 and LaOCuS nanolayered particles synthesized via these soft chemistry routes exhibit all the characteristics of transparent p-type semiconductors