Solvothermal synthesis of chalcopyrite CuIn0.7Ga0.3Se2 nanoparticles and the studies on reaction mechanism and structure defects

•Chalcopyrite CuIn0.7Ga0.3Se2 nanoparticles have been successfully synthesized by using solvothermal method.•The higher the temperature is, the more gallium dope into the obtained product.•The size of the nanoparticles range from 20 nm to 100 nm.•The product is slightly poor in copper as the consequence of defect structures analysis and XPS datas.

By using a solvothermal reaction in ethylenediamine, quaternary chalcopyrite CuIn0.7Ga0.3Se2 nanoparticles have been successfully synthesized at 270 °C. The nanoparticles were characterized by XRD, XPS, TEM, HRTEM. The possible reaction mechanism was simply discussed. The size of nanoparticles ranged from 20 nm to 100 nm, being consistent with the calculated value. We observed point defects and planar defects by using TEM, and the possible formation mechanism was also discussed.