Single source precursor route to nanometric tin chalcogenides

Impact of FeS on the TiO2 Layer As Support System in QDSCs

We report on the passivation of titanium oxide with FeS from three molecular precursors with tin sulfide (SnS) photon absorbers that were fabricated and assembled to increase the performance of quantum dot sensitized solar cells (QDSSCs). FeS was loaded on the TiO2 surfaces, and then, SnS photosensitizer was deposited to form a ternary modified device. The morphology, structural structure, size distribution, chemical composition, and conversion efficiency were explored by FE-SEM, XRD, TEM, UV-vis, EDS, EIS, and J-V analysis. The CV, LSV, and stability state were also investigated for migration and separation of photogenerated charge carriers in the as-prepared cells labeled F-S-1, F-S-2, and F-S-3. The FE-SEM image of the F-S-2 cell is composed of FeS interconnected with SnS and FeS, which provided paths for electron movement compared with the F-S-1 and F-S-3 devices. The semicircle for the F/S-1 and F/S-3 solar device diameters illustrates that the high-medium frequency regain is greater than that of the F/S-2 device, implying that both cells have charge-transfer impedances and lower contact. Apparently, the F/S-2 device shows superior catalytic activity, which can be linked to the hybridization of TiO2/FeS/SnS due to the synergistic effect. The F/S-2/S-2l has a maximum efficiency η of 6.73% in comparison to F/S-1 and F/S-3, which have the same conversion efficiency of 3.82%. The results of the F/S-2 device follow a similar trend to the chronoamperometry analysis, CV, and LSV results from this study.

Understanding vapor phase growth of hexagonal boron nitride

Hexagonal boron nitride (hBN), with its atomically flat structure, excellent chemical stability, and large band gap energy (∼6 eV), serves as an exemplary 2D insulator in electronics. Additionally, it offers exceptional attributes for the growth and encapsulation of semiconductor transition metal dichalcogenides (TMDCs). Current methodologies for producing hBN thin films primarily involve exfoliating multi-layer or bulk crystals and thin film growth via chemical vapor deposition (CVD), which entails the thermal decomposition and surface reaction of molecular precursors like ammonia boranes (NH3BH3) and borazine (B3N3H6). These molecular precursors contain pre-existing B-N bonds, thus promoting the nucleation of BN. However, the quality and phase purity of resulting BN films are greatly influenced by the film preparation and deposition process conditions that remain a substantial concern. This study aims to comprehensively investigate the impact of varied CVD systems, parameters, and precursor chemistry on the synthesis of high-quality, large scale hBN on both catalytic and non-catalytic substrates. The comparative analysis provided new insights into most effective approaches concerning both quality and scalability of vapor phase grown hBN films.

Synthesis and theoretical study of a mixed-ligand indium(III) complex for fabrication of β-In2S3 thin films via chemical vapor deposition

Two new heteroleptic indium aminothiolate compounds [InClSC2H4N(Me)SC2H4]3[1] and [InSC2H4N(Me)SC2H4(C8H5F3NO)] [2] were synthesized by in situ salt metathesis reaction involving indium trichloride, aminothiol, and N,O-β-heteroarylalkenol ligands. The complexes were subsequently purified and thoroughly characterized by nuclear magnetic resonance (NMR) analysis, elemental studies, mass spectroscopy, and X-ray diffraction single crystal analysis that showed a trigonal bipyramidal coordination of In(III) in both complexes. Thermogravimetric analysis of [1] revealed a multistep decomposition pathway and the formation of In2S3 at 350 °C, which differed from the pattern of [2] due to the lower thermal stability of [1]. Compound [2] exhibited a three-step decomposition process, resulting in the formation of In2S3 at 300 °C. The Chemical Vapor Deposition (CVD) experiment involving compound [2] was conducted on the FTO substrate, resulting in the production of singular-phase In2S3 deposits. A comprehensive characterization of these deposits, including crystal structure analysis via X-ray diffraction (XRD), and surface topography examination through scanning electron microscopy (SEM) has been completed. The presence of In-S units was also supported by the Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDS) of the as-deposited films. Moreover, the electronic structure and thermal properties of compound [2] were investigated through DFT calculations. Electron density localization analysis revealed that the highest occupied molecular orbital (HOMO) exhibited dense concentration at the aminothiolate moiety of the complex, while the lowest unoccupied molecular orbital (LUMO) predominantly resided at the N,O-β-heteroarylalkenolate ligand. Furthermore, our computational investigation has validated the formation of indium sulfide by elucidating an intermediate state, effectively identified through EI-MS analysis, as one of the plausible pathways for obtaining In2S3. This intermediate state comprises the aminothiolate ligand (LNS) coordinated with indium metal.