Synthesis of Cu2ZnxSnySe1+x+2y nanocrystals with wurtzite-derived structure

Abstract

The most reported stable crystal structure of Cu 2 ZnSnS 4 and Cu 2 ZnSnSe 4 (CZTSe) is kesterite, which is derived from the ternary chalcopyrite structure. However, by controlling the reaction conditions, we found that the structure and composition of the CZTSe nanocrystals (NCs) can be tuned. This can be achieved by using a simple hot injection approach. The structural properties of the CZTSe NCs were characterized by powder X-ray diffraction (PXRD), Raman spectroscopy and transmission electron microscopy. The energy dispersive X-ray spectroscopy confirms the stoichiometry of CZTSe NCs. The optical band gap of the NCs is found to be around 1.38 eV, as estimated from UV-Vis absorption spectroscopy. PXRD studies show that the obtained CZTSe NCs occurring in three structurally different phases (tetragonal kesterite type, hexagonal wurtzite type and orthorhombic wurtz-stannite type) are converted to the kesterite structure by annealing at 540 uC for 30 min under an Se-vapour atmosphere.

Phase-transition-driven growth of compound semiconductor crystals from ordered metastable nanorods

“…1a for a larger angle range). In the literature nanocrystals with orthorhombic wurtz-stannite and pseudo-orthorhombic wurtz-kesterite structures are reported [27][28][29][30][31] which produce similar diffraction signals due to a similar hexagonal anion sublattice, but differ in the ordering of the cations [30]. In our measurements, additional reflexes that indicate presence of wurtz-stannite or wurtz-kesterite instead of hexagonal wurtzite structure are not observed.…”

Alloyed Copper Chalcogenide Nanoplatelets via Partial Cation Exchange Reactions

“…17 A similar mechanism has also been proposed by Shavel et al for the growth of CZTS NCs starting with the nucleation of Cu 2 S particles, followed by subsequent intercalation of Zn and Sn ions into the NC structure. 26 In such direct synthesis, the main drawback is that the incomplete conversion of Zn- and Sn-precursors into CZTSe NCs (30% of Sn and only 3% of Zn were incorporated) 29 leads to zinc- and/or tin-poor nonstoichiometric compounds, 33 which actually hinders the control on the composition of NCs. Additionally, in some cases, the particles exhibit an inhomogeneous distribution of elements, in particular Zn and Sn, over the quaternary NCs.…”

Characterization of Cu2ZnSnSe4 (CZTSe) nanoparticles synthesized via solvothermal method for solar cell applications

“…Ethylenediamine-capped particles are known to coalesce to form nanoclusters, which further agglomerate into petals and sheet-like microstructures, owing to the template effect of En [34]. Similar morphologies were obtained using zinc chloride, zinc acetate, zinc nitrate, zinc sulphate and acetylacetonate.…”

“…Another peak at 239 cm -1 could beattributed to SnSe x (Fig. 2a) [34]. When the solvothermal temperature was increased to 220°C, two Raman peaks at 239 and 258 cm -1 , corresponding to SnSe x and ZnSe respectively, were (obtained OR observed) (Fig.…”