Effect of reaction temperature on the properties of Cu_2ZnSnS_4 nanocrystals prepared using a hot injection method

摘要

Cu_2ZnSnS_4 nanocrystals have been fabricated using a hot injection method and the properties of the nanocrystals have been investigated as a function of the reaction temperature. When the reaction temperature was increased from 195 °C to 240 °C the grain size increased and the energy band gap of the nanocrystals was found to decrease from 1.71 eV to 1.39 eV. X-ray diffraction and Raman data indicated the presence of both a wurtzite phase and a kesterite phase of Cu_2ZnSnS_4 for the nanocrystals formed at the lower reaction temperatures whereas cubic Cu_2SnS_3 was found to be present for the higher reaction temperatures used. Optimising the reaction temperature resulted in the formation of kesterite Cu_2ZnSnS_4 nanocrystals suitable for use in solar cell devices.