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

Abstract

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.

Path towards high-efficient kesterite solar cells

“…Nanocrystal synthesis is a general chemical method which makes it possible for metastable phases to be readily accessible at low temperatures in the nanometer size regime with some organic or inorganic capping ligands that control nanocrystal growth and disperse nanocrystal from agglomeration. A very wide range of chalcogenides semiconductor materials can be generated based on this technique, such as popular photovoltaic (PV) material, Cd(S,Se) [93][94][95] , Pb(S,Se) [96][97][98] , CIGSSe [99][100][101][102] , CZTSSe [103][104][105][106][107] . And the specific techniques developed for the synthesis of these colloidal nanocrystals embrace aqueous and non-aqueous coprecipitation, hydrothermal/solvothermal process, sol-gel process, and template directed growth [108][109][110] .…”

A nontoxic and low-cost hydrothermal route for synthesis of hierarchical Cu2ZnSnS4 particles

“…Thus, increasing attention has been paid on CZTS materials in recent years [6-10]. Low-cost solar cells based on CZTS films as absorber layers have achieved an increasing conversion efficiency [11-15].…”

Colloidal synthesis of CuGaS x Se 2 − x nanoribbons mediated by Cu 1.75 (SSe) nanocrystals as catalysts

“…Very recently, the SSS mechanism proposed by Wang [38] for nanowire growth provided the clear understanding about the state and structure of catalysts, whose exceptional catalytic ability originated from high-density vacancies and fast mobility of cations. Since 2008, Cu 2 S [30,31], Cu 1.94 S [32,33], Cu 1.75 S [34], Ag 2 S [35,36] and Ag 2 Se [37][38][39] nanocrystals have been found to be the effective catalysts in solution synthesis of nanowires for their intrinsic nature of fast ionic conductor. As one of the fast ionic conductors, Cu 1.75 (SSe) lattice also has the high-density vacancies and fast mobility of copper cations in the rigid sublattice of Se 2À and S 2À [38], promoting the dissolution of gallium ions and their diffusion from the surface to the interface, which made Cu 1.75 (SSe) nanoparticles act as host.…”

“…In their research, metallic nanoparticles [29], such as Bi and In, usually acted as the catalysts in the growth of 1D nanomaterials. Recently, metal sulfide nanocrystals (Cu 2 S [30,31], Cu 1.94 S [32,33], Cu 1.75 S [34], Ag 2 S [35,36] and Ag 2 Se [37][38][39]) have also been found to be the effective catalysts in solution synthesis of nanowires for the intrinsic nature of fast ionic conductor. Specifically, Wang et al [38] proposed the novel Solution-Solid-Solid (SSS) mechanism for nanowire growth catalyzed by superionic ( for the growth of 1D nanomaterial, especially in the region of the fast ionic conductors.…”