Electrodeposition of Niobium from 1-Butyl-1-Methylpyrrolidinium bis(trifluoromethylsulfonyl)amide Ionic Liquid

Controllable Multinary Alloy Electrodeposition for Thin-Film Solar Cell Fabrication: A Case Study of Kesterite Cu2ZnSnS4

Electrodeposition (ED) technology is a low-cost industrial candidate for solar cell fabrication. However, the practical aspects of controlling deposit morphology and composition have not been significantly addressed because of the complex co-plating variables that still need to be understood for multinary alloy ED. This work addresses these practical aspects on how to control composition and deposit morphology using co-electrodeposited kesterite alloy precursors as a case study. The alloy precursors co-plated under the optimized conditions from a mixed thiosulfate-sulfite electrolyte bath show uniform, smooth, and compact film morphology as well as uniform distribution of composition, well suited for efficient kesterite absorbers, finally delivering a Cu₂ZnSnS₄ (CZTS) thin-film solar cell with 7.4% efficiency based on a configuration Mo/CZTS/CdS/ZnO/aluminum-doped ZnO. This work underscores that alloy ED, with the advantage of controllable composition and morphology, holds promise for low-cost industrial manufacture of thin-film solar cells.

•

Simultaneous control of the composition and morphology of the alloy electrodeposit

•

Alloy electrodeposits with superb uniformity in film appearances and compositions

•

The best kesterite Cu₂ZnSnS₄ mini solar cell with a 7.4% power conversion efficiency

Modifying bis(triflimide) ionic liquids by dissolving early transition metal carbamates

The authors report the first modification of ionic liquids with metal carbamates. A selection of homoleptic N,N-dialkylcarbamates of group 4 and 5 metals, M(O₂CNR₂)_n, were dissolved in bis(trifluoromethylsulfonyl)imide-based ionic liquids, i.e. [bmim][Tf₂N] and [P(oct)₄][Tf₂N], at 293 K. The resulting solutions were characterized by means of IR, UV and NMR spectroscopy, and the data were compared to those of the respective metal compounds. Notably, the dissolution process did not proceed with the release of any of the original carbamato ligands, thus preserving the intact coordination frame around the metal centre. The solvation process of Ti(O₂CNⁱPr₂)₄, as a model species, in [bmim][Tf₂N] was rationalized by DFT calculations. As a comparative study, solutions of NbF₅ and MCl₅ (M = Nb, Ta) in [bmim][Tf₂N] were also investigated, revealing the possible occurrence of solvent anion coordination to the metal centres.

Electrodeposition in Ionic Liquids

Due to their attractive physico-chemical properties, ionic liquids (ILs) are increasingly used as deposition electrolytes. This review summarizes recent advances in electrodeposition in ILs and focuses on its similarities and differences with that in aqueous solutions. The electrodeposition in ILs is divided into direct and template-assisted deposition. We detail the direct deposition of metals, alloys and semiconductors in five types of ILs, including halometallate ILs, air- and water-stable ILs, deep eutectic solvents (DESs), ILs with metal-containing cations, and protic ILs. Template-assisted deposition of nanostructures and macroporous structures in ILs is also presented. The effects of modulating factors such as deposition conditions (current density, current density mode, deposition time, temperature) and electrolyte components (cation, anion, metal salts, additives, water content) on the morphology, compositions, microstructures and properties of the prepared materials are highlighted.