Synthesis of Cu₂SnSe₃ nanocrystals for solution processable photovoltaic cells

This paper describes the synthesis of ternary chalcogenide Cu ₂SnSe₃ nanocrystals as an alternative solar absorber material to conventional quaternary CuIn_xGa_1-xSe ₂. We used the hot coordination solvent method with hexadecylamine as the capping ligand for the first time for this material system. Using a variety of characterization techniques, such as X-ray diffraction, selected area electron diffraction, convergent beam electron diffraction, and Raman spectroscopy, the nanocrystals were found to be monoclinic Cu ₂SnSe₃ with an optical energy band gap of 1.3 eV and have a narrow size distribution. These nanocrystals are shown to be photosensitive in the range of wavelengths corresponding to the solar spectrum, which makes them highly promising as alternative photon absorber materials for photovoltaic applications.