Thiourea-Derived Single-Source Molecular Precursor For Spin-Coated PbS Thin Films

In search of a suitable single-source precursor for the deposition of nanostructured PbS thin films at moderate temperatures under ambient conditions, we have synthesized the ligand N-(thiomorpholine-4-carbothioyl)benzamide and its corresponding lead(II) complex. The structures of both compounds were determined by single-crystal X-ray diffraction. In the complex, two ligands coordinate to a lead(II) atom in hemi-directed geometry through S and O atoms. Secondary intermolecular Pb⋅⋅⋅S interactions group the complexes into pairs. As bulk powders, both the ligand and complex show nominal composition and purity as evidenced by elemental analysis, ¹ H NMR and IR spectroscopy. Thermal analysis of the lead(II) complex was carried out to understand its thermal decomposition behaviour for establishing a thin film fabrication protocol. Thin films of phase-pure PbS were fabricated using this new molecular precursor at the comparatively low annealing temperature of 250 °C. The film showed nanoparticles with cuboidal morphology and a blue-shifted optical absorption.

Synthesis of photoresponsive and photoemissive ultrathin 2D nanosheets of In2S3 achieved through a new single source molecular precursor

Indium sulfide, a two-dimensional semiconductor material, has emerged as a promising candidate for cost-effective and sustainable solar cells. This report deals with the facile preparation of colloidal In₂S₃ with a new ultrathin nanosheet (NS) morphology. The synthesis was mediated through a new structurally characterized single source molecular precursor. The crystal structure, phase purity, and morphology of the NSs were thoroughly investigated by pXRD, Raman, XPS, and electron microscopic techniques. AFM studies revealed that the NSs have an average thickness of ∼1.76 nm. The optical studies confirm quantum confinement in the as-prepared NSs with a blue shift in the direct band gap, which lies in the optimal range suitable for solar cell application. Furthermore, photoluminescence studies indicate strong emission by these NSs in the blue region. The as-synthesized In₂S₃ NSs-based prototype photoelectrochemical cell exhibit high photostability and photoresponsivity, which make them suitable candidates for sustainable solar cells.

Quantum confined ultrathin nanosheets of In₂S₃ were synthesized from a new structurally characterized molecular precursor. The prototype photoelectrochemical cell based on the material exhibited high photostability and photoresponsivity.

Synthesis, optical and structural characterisation of ZnS nanoparticles derived from Zn(ii) dithiocarbamate complexes

Zinc sulphide nanoparticles represented as ZnS1, ZnS2 and ZnS3 have been prepared from Zn(ii) N-methyl-N-ethanoldithiocarbamate (1) complex and its 2,2′-bipyridine (2) and 1,10′-phenanthroline (3) adducts, respectively. Both the parent complex (1) and the adducts (2) and (3) were characterised by spectroscopic techniques and elemental analysis. In the solid state, the structures of complexes (1) and (2) were established using single-crystal X-ray analysis. Complex (1) possessed a distorted trigonal bipyramidal geometry about the zinc centre, whilst forming a dimer via bidentate bridging coordination between two opposite dithiocarbamate motifs. On the other hand, complex (2) formed a trigonal prismatic geometry about the Zn centre with a ZnS4N2 chromophore. The decomposition of the complexes in hexadecylamine afforded spherical-shaped ZnS nanoparticles of the cubic sphalerite crystal phase. The transmission electron microscopy (TEM) micrographs showed that the average particles size of ZnS1, ZnS2 and ZnS3 were 2.63, 5.27 and 6.52 nm, respectively. In the optical study, the estimated bandgap energies were found in the range between 4.34 and 4.08 eV, which indicated a blue shift when compared with the bandgap energy of bulk ZnS.

Dimethyltin(IV)-4,6-dimethyl-2-pyridylselenolate: an efficient single source precursor for the preparation of SnSe nanosheets as anode material for lithium ion batteries

The air stable tin(IV) complex [Me₂Sn{2-SeC₅H₂(Me-4,6)₂N}₂] has been synthesized, characterized by NMR, elemental analysis, and single crystal XRD, and employed as a single source molecular precursor (SSP) for the facile synthesis of orthorhombic SnSe nanosheets. The crystal structure, phase purity, morphology and band gap of the nanosheets were investigated by pXRD, EDS, electron microscopy and diffuse reflectance spectroscopy techniques, respectively. It was found that the preferential orientation of planes and the morphology of the nanosheets rely upon the reaction conditions. The band gaps of the nanosheets were blue shifted with respect to the bulk band gap of the material. The synthesized SnSe nanosheets have been employed as an anode material in lithium ion batteries (LIBs). The material exhibits an initial specific capacity of 1134 mA h g^-1 at a current density of 50 mA g^-1 and was found to retain a capacity of 380 mA h g^-1 even after 70 cycles with 100% efficiency.

Dithiocarbamate Complexes as Single Source Precursors to Nanoscale Binary, Ternary and Quaternary Metal Sulfides

Nanodimensional metal sulfides are a developing class of low-cost materials with potential applications in areas as wide-ranging as energy storage, electrocatalysis, and imaging. An attractive synthetic strategy, which allows careful control over stoichiometry, is the single source precursor (SSP) approach in which well-defined molecular species containing preformed metal-sulfur bonds are heated to decomposition, either in the vapor or solution phase, resulting in facile loss of organics and formation of nanodimensional metal sulfides. By careful control of the precursor, the decomposition environment and addition of surfactants, this approach affords a range of nanocrystalline materials from a library of precursors. Dithiocarbamates (DTCs) are monoanionic chelating ligands that have been known for over a century and find applications in agriculture, medicine, and materials science. They are easily prepared from nontoxic secondary and primary amines and form stable complexes with all elements. Since pioneering work in the late 1980s, the use of DTC complexes as SSPs to a wide range of binary, ternary, and multinary sulfides has been extensively documented. This review maps these developments, from the formation of thin films, often comprised of embedded nanocrystals, to quantum dots coated with organic ligands or shelled by other metal sulfides that show high photoluminescence quantum yields, and a range of other nanomaterials in which both the phase and morphology of the nanocrystals can be engineered, allowing fine-tuning of technologically important physical properties, thus opening up a myriad of potential applications.

PbS Nanoparticles Prepared Using 1, 10-Phenanthroline Adduct of Lead(II) Bis(N-alkyl-N-phenyl dithiocarbamate) as Single Source Precursors

Dithiocarbamate complexes have remained prominent as single source precursors for the synthesis of clean metal sulfide nanoparticles. This study reports the synthesis of lead sulfide (PbS) nanoparticles using some novel complexes of 1, 10-phenanthroline lead(II) bis(N-alkyl-N-phenyl dithiocarbamate), represented as [Pb(L¹)₂phen] (1) and [Pb(L²)₂phen] (2) (where L¹ = bis(N-ethyl-N-phenyldithiocarbamate; L² = bis(N-butyl-N-phenyldithiocarbamate); phen = 1, 10 phenanthroline) as a single source precursors. The complexes (1 and 2) were synthesized and characterized using various spectroscopic techniques and elemental analysis. The nanoparticles were synthesized via a solvothermal approach in oleylamine, used as a capping agent, and were given as PbS(1) and PbS(2) from [Pb(L¹)₂phen] (1) and [Pb(L²)₂phen] (2), respectively, which were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and absorption spectroscopy. The diffraction patterns confirmed the formation of face-centered cubic phase PbS nanoparticles with a preferential growth orientation along the (200) plane. The TEM images showed that PbS(1) were of a spherical morphology, while the morphology of PbS(2) tended to produce short rods. This was due to variation in the functional group on the precursor compounds. This variation also resulted in the different band gap energies found such as 1.148 and 1.107 eV for PbS(1) and PbS(2), respectively, indicating a blue shift from the bulk.

Lead ethyl dithiocarbamates: efficient single-source precursors to PbS nanocubes

Lead ethyl dithiocarbamates have been successfully used as single-source precursors for the deposition of PbS using spin coating followed by annealing at moderate temperatures. The thin films were characterized using a powder X-ray diffractometer and were found to be face-centred cubic with the (200) plane being the most preferred orientation. Scanning electron microscopy images showed the formation of well-defined cubes. Optical band gaps of PbS thin films were estimated using Tauc plots as 0.72, 0.73 and 0.77 eV at annealing temperatures of 250, 300 and 400°C. These band gaps were all blue shifted from the bulk value of 0.41 eV. Energy-dispersive X-ray analysis was used to determine the composition of the thin films which showed an approximately 1 : 1 Pb to S ratio.

Bis(selenobenzoato)dibutyltin(iv) as a single source precursor for the synthesis of SnSe nanosheets and their photo-electrochemical study for water splitting

A new organo tin complex has been synthesized and used as a single source precursor for the synthesis of tin selenide nanosheets and deposition of thin films.

Effect of cationic disorder on the energy generation and energy storage applications of NixCo3−xS4 thiospinel

Thiospinels show interesting catalytic and energy storage applications, however, the cationic disorder can have major influence on the energy generation and/or energy storage applications.

Facile synthesis of a PbS1−xSex (0 ≤ x ≤ 1) solid solution using bis(N,N-diethyl-N′-naphthoylchalcogenoureato)lead(ii) complexes

A precise composition and band gap tunable PbS_1−xSe_x solid solution was prepared by a single source route.

A magnetically recyclable iron oxide-supported copper oxide nanocatalyst (Fe3O4–CuO) for one-pot synthesis of S-aryl dithiocarbamates under solvent-free conditions

A convenient preparation of S-aryl dithiocarbamates from amine, carbon disulfide and aryl iodide was developed by using the Fe₃O₄–CuO nanocatalyst under solvent free conditions.

Dendritic CdS assemblies for removal of organic dye molecules

In this paper, novel CdS 3D assemblies are prepared via a facile and effective hydrothermal route using dimethyl sulfoxide as the growth template.

Tilted face-centered-cubic supercrystals of PbS nanocubes

We demonstrate a direct fabrication of PbS nanocube supercrystals without size-selection pretreatment on the building blocks. Electron microscopic and synchrotron small angle X-ray scattering analyses confirm that nanocubes pack through a tilted face-centered-cubic (fcc) arrangement, that is, face-to-face along the <110>(super) direction, resulting in a real packing efficiency of as high as ∼83%. This new type of superstructure consisting of nanocubes as building blocks, reported here for the first time, is considered the most stable surfactant-capped nanocube superstructure determined by far.