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Cu2ZnSn(S,Se)4 (CZTSSe) are benign and low-cost materials, overcoming the limitations of toxicity and high costs of other semiconductors such as CuInGa(S,Se)2, cadmium and lead chalcogenides, and Pb-based perovskites widely used in photovoltaic and thermoelectric applications. In order to shed light on the formation mechanism of CZTS nanoparticles using anisole as the solvent, oleylamine as the organic ligand, carbon disulphide as the sulphur source and Zn(NO3)2·6H2O as the Zn(II) precursor, we follow the conversion of binary sulphides formed in situ under solvothermal conditions into quaternary phases. Besides a careful microstructural characterization of the as-synthesized materials by X-ray diffraction (XRD), Raman spectroscopy, electron microscopy (TEM and HRTEM) and energy dispersive X-ray (EDX) spectroscopy at micron- and nano-scale, we study the evolution of particle surface properties by X-ray-photoelectron spectroscopy (XPS). The results show that CZTS particles form already during the early stages of the reaction, most probably through a nucleation and growth mechanism. In parallel, a comparably slower growth mechanism is observed that involves recrystallization between the binary phases, without evidence of ternary phase formation.

Cu2ZnSnS4 and Cu2ZnSnSe4 (CZTS and CZTSe, respectively) and their mixed chalcogenide phase Cu2ZnSnSxSe4-x (CZTSS(e)) are benign and cheap photovoltaic absorber materials that represent a valuable alternative to the more expensive chalcogenide systems: i.e., Cu(In,Ga)SS(e)2 (CIGSS(e)). One of the main challenges related to the fabrication of CZTS(e) layers is the control over both the crystalline phase (tetragonal, cubic, or hexagonal) and the formation of binary (MS, M = Cu(II), Zn(II), Sn(II); M'2-xS, M'= Cu(I), x = 0, 0.2; M″S2, M″ = Sn(IV)) and ternary products (CTS phases, Cu2SnS3, Cu3SnS4) that hinder the performance of the corresponding devices. In the present work, we rationalize the formation pathway of the CZTS phase through binary and ternary products when salt precursors with chloride and acetate as counteranions, respectively, are employed. The results show that the counteranions have a remarkable influence on the formation pathway of CZTS nanoparticles. The use of chloride precursors leads to the predominant formation of CTSs ternary phases (Cu2SnS3, Cu3SnS4), whereas the formation of the CZTS phase is not observed even for higher temperature and longer reaction time (250 °C, 24 h). In the case of acetates the copresence of CZTS as the main product, together with binary and ternary phases, is observed in the early stages of the reaction even at lower temperature and shorter reaction time (200 °C, 2 h), while when the reaction time and temperature are increased, only the CZTS phase is observed. In addition to a careful microstructural characterization of the as-synthesized materials by Raman spectroscopy, X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HRTEM), we shed light on the reactivity among the metal precursors, the organic ligand oleylamine, and the sulfur precursor carbon disulfide (CS2) by 13C nuclear magnetic resonance (13C NMR) and investigate in depth the effect on particle surfaces by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and XPS. A rationale for the formation pathway of CZTS nanoparticles is proposed and supported by experimental evidence.

Since the discovery of silicone nanofilaments a decade ago, room temperature droplet assisted growth and shaping using silanes has been used to synthesize various silicone-based nanostructures. In the present work, we report an extension of this synthesis technique to synthesize nanostructures of new materials. We have successfully synthesized one-dimensional assemblies of beads or necklaces based on alumina (Al) and mixed alumina-silicone (AlSi) nanostructures exhibiting a similar structure as silicone nanofilaments. The characterization of the synthesized nanostructures was performed using different tools, including scanning and transmission electron microscopy, energy dispersive x-ray spectroscopy, and infrared and NMR spectroscopy. Selected area electron diffraction revealed that the nanostructures are amorphous in nature, and the growth behavior and thermal stability of nanostructures are also discussed.

Cu

Germanium oxide nanofilaments (GNFs) have been synthesized under ambient conditions from the gas phase using germanium tetrachloride as a precursor. Non-crystalline GNFs synthesized by this procedure are 1-10 μm in length and 80-110 nm in diameter applying Droplet Assisted Growth and Shaping (DAGS) Chemistry. The relative humidity has been adjusted at various values in order to demonstrate the crucial role of humidity in the gas phase for the nanofilament synthesis. The novel GNFs show a strong luminescence emission in the ultra-violet and light blue region. In addition, a self-cleaning and superhydrophobic properties could be introduced in the luminescent GNF nanofilaments by simple treatment with silane molecules.

In this study, the fabrication of superhydrophobic and conductive coatings applying a facile coating method is reported. The droplet‐assisted growth and shaping (DAGS) method is used to synthesize silicone nanofilament–based superhydrophobic coatings. Dip coating of superhydrophobic substrates in carbon nanofiber suspensions is performed to prepare superhydrophobic/conductive coatings. The prepared coatings combine electric conductivity, optical transparency, and superhydrophobicity with low sliding angles. The coatings show stability to water immersion and exposure to extreme humid conditions. Also, they exhibit good chemical resistance after several days of immersion in acidic and basic aqueous solutions. A key factor of such coatings is the mechanical durability which is improved by the addition of Parafilm‐M

In pursuit of designing novel biocompatible scaffold for hydroxyapatite (HA) growth, silicone nanofilaments coated surfaces have been investigated. High surface area of these 1-D nanofilaments offers large density of nucleation sites for biomineralization. The study shows that the amine and carboxylic acid functionalized SNFs enhance mineralization of HA particles whereas monolayer modified glass substrate did not show HA nucleation during the same period of time. Further investigation demonstrated the growth kinetics of HA particles and revealed that a dense and uniform coating of HA could be achieved after 7 days of immersion in simulated body fluid (SBF). This fast and facile approach could open up a new avenue for bone mineralization.