Preparation of lanthanum sulfide nanoparticles by thermal decomposition of lanthanum complex

γ-La2S3 nanoparticles were successfully prepared by thermal decomposition of lanthanum complex La（Et2S2CN）3·phen at low temperature. The obtained sample was characterized by the X-ray powder diffraction （XRD）, scanning electron microscopy （SEM） and element analysis. The decomposition mechanism of lanthanum complex was studied by thermogravimetric analyses （TGA）. The results showed that the obtained samples were cubic phase particles with uniform sizes among 10–30 nm and γ-La2S3 was prepared by decomposition of La（Et2S2CN）3·phen via La4（Et2S2CN）3 as an intermediate product. The band gap of γ-La2S3 was 2.97 eV, which was bigger than bulk crystal because of pronounced quantum confinement effect.