Cu₂ZnSnS₄ Nanorods Doped with Tetrahedral, High Spin Transition Metal Ions: Mn²⁺, Co²⁺, and Ni²⁺

Abstract

Because of its useful optoelectronic properties and the relative abundance of its elements, the quaternary semiconductor Cu 2 ZnSnS 4 (CZTS) has garnered considerable interest in recent years. In this work, we dope divalent, high spin transition metal ions (M 2+ = Mn 2+ , Co 2+ , Ni 2+ ) into the tetrahedral Zn 2+ sites of wurtzite CZTS nanorods. The resulting Cu 2 M x Zn 1−x SnS 4 (CMTS) nanocrystals retain the hexagonal crystalline structure, elongated morphology, and broad visible light absorption profile of the undoped CZTS nanorods. Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and infrared (IR) spectroscopy help corroborate the composition and local ion environment of the doped nanocrystals. EPR shows that, similarly to Mn x Cd 1−x Se, washing Cu 2 Mn x Zn 1−x SnS 4 nanocrystals with trioctylphosphine oxide (TOPO) is an efficient way to remove excess Mn 2+ ions from the particle surface. XPS and IR of as-isolated and thiol-washed samples show that, in contrast to binary chalcogenides, Cu 2 Mn x Zn 1−x SnS 4 nanocrystals aggregate not through dichalcogenide bonds, but through excess metal ions cross-linking the sulfur-rich surfaces of neighboring particles. Our results may help in expanding the synthetic applicability of CZTS and CMTS materials beyond photovoltaics and into the fields of spintronics and magnetic data storage.

Structural and Electronic Properties of Cu2MnSnS4 from Experiment and First‐Principles Calculations

“…In literature, some reports can be found claiming kesterite as the crystal structure for Cu 2 MnSnS 4 . However, most studies assume that Cu 2 MnSnS 4 attains the stannite crystal structure based on results from neutron diffraction, where the stannite symmetry group yields a slightly better fit to the neutron diffraction data compared to the kesterite symmetry group .…”

Multifunctional Copper‐Based Quaternary Chalcogenide Semiconductors Toward State‐of‐the‐Art Energy Applications

“…Similarly, many other quaternary chalcogenides such as CCTS, CFTS, CMTS, CNTS and hybrids of quaternary chalcogenides with magnetic metals such as CZTS‐NiPt, CZTS‐CoPt etc. have been explored for emerging applications in magneto‐electrical devices ,,,…”

Optimization of Cu2ZnSnS4 Absorber Layers via Sulfurization of Electrodeposited Cu-Zn-Sn Precursors for Photovoltaic Applications

“…Electrodeposition furthermore can be used to study other promising growth modifier metals. In particular, Ni and Co could be studied, since they have been reported to modify the lattice constant and band gap of the CZTS and promote better band alignment at the Cd/CZTS interface [198][199][200]. Furthermore, cobalt and nickel can be co-electrodeposited from a citrate based solution owing to their suitable reduction potential in the Cu-Zn-Sn electrodeposition system as an alternative simple method to dope CZTS films [76,201,202].…”

“…Furthermore, cobalt and nickel can be co-electrodeposited from a citrate based solution owing to their suitable reduction potential in the Cu-Zn-Sn electrodeposition system as an alternative simple method to dope CZTS films [76,201,202]. Cobalt-containing Cu 2 Co x Zn 1-x SnS 4 and Cu 2 CoSnS 4 materials have been grown as nanofibers and nanorods before [198,203]; however, a low doping amount in CZTS films for the modification of CdS/CZTS band alignment has not been reported as yet. Nickel containing Cu 2 Ni x Zn 1-x SnS 4 and Cu 2 NiSnS 4 materials have been grown as a film, nanofiber and nanorods [198,199,203]; nevertheless none of these studies reported the photoelectrochemical or solar cell performance of these materials.…”

“…Cobalt-containing Cu 2 Co x Zn 1-x SnS 4 and Cu 2 CoSnS 4 materials have been grown as nanofibers and nanorods before [198,203]; however, a low doping amount in CZTS films for the modification of CdS/CZTS band alignment has not been reported as yet. Nickel containing Cu 2 Ni x Zn 1-x SnS 4 and Cu 2 NiSnS 4 materials have been grown as a film, nanofiber and nanorods [198,199,203]; nevertheless none of these studies reported the photoelectrochemical or solar cell performance of these materials. Cobalt containing CZTS films can be synthesized via sulfurization of co-electrodeposited Cu-Zn-Sn-Co metallic precursors on Mo substrate with varying compositional ratios for the optimization of band gap as well as band alignment for CdS/CZTS interface.…”