Solution-based synthesis of wurtzite Cu2ZnSnS4 nanoleaves introduced by α-Cu2S nanocrystals as a catalyst

Cu2ZnSnS4 is a promising solar absorbing material in solar cells due to its high absorption coefficient and abundance on earth. We have demonstrated that wurtzite Cu2ZnSnS4 nanoleaves could be synthesized through a facile solution-based method. Detailed investigation of the growth process indicates that α-Cu2S nanocrystals are first formed and then serve as a catalyst to introduce the Cu, Zn, and Sn species into the nanoleaf growth for fast ionic conduction. The structure of the as-synthesized nanoleaves is characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, fast Fourier transform, and energy dispersive X-ray spectroscopy mapping. Photoresponses of Cu2ZnSnS4 nanoleaves are evaluated by I-V curves of a Cu2ZnSnS4 nanoleaf film. It is believed that the enhancement of the photoresponse current of the Cu2ZnSnS4 nanoleaf film can be attributed to fast carrier transport due to the single crystalline nature and enhanced light absorption resulting from larger absorption areas of the Cu2ZnSnS4 nanoleaves.