Synthesis of shape-controlled monodisperse wurtzite CuIn_xGa _1-xS₂ semiconductor nanocrystals with tunable band gap

Monodisperse wurtzite CuIn_xGa_{1 - x}S₂ nanocrystals have been synthesized over the entire composition range using a facile solution-based method. Depending on the chemical composition and synthesis conditions, the morphology of the nanocrystals can be controlled in the form of bullet-like, rod-like, and tadpole-like shapes. The band gap of the nanocrystals increases linearly with increasing Ga concentration, with band gap values for the end members being close to those observed in the bulk. Colloidal suspensions of the nanocrystals are attractive for use as inks for low-cost fabrication of thin film solar cells by spin or spray coating.