Atomic Layer Deposition of MnS: Phase Control and Electrochemical Applications

Colloidal Synthesis of γ-MnS Nanorods with Uniform Controlled Size and Pure ⟨002⟩ Growth Direction

One dimensional (1D) compound semiconductor nanostructures have unique anisotropic optical, electrical, and physical properties. Synthesis of large scale 1D nanostructures with pure crystallographic growth direction by a colloidal route and finding an easy method to prove it were significant for further exploring their unique anisotropic properties. Additionally, MnS is one of the most important optoelectronic and magnetic semiconductors. Herein, the large scale γ-MnS nanorods with completely pure ⟨002⟩ growth direction were first synthesized and convinced by solid evidence using the X-ray diffraction method. Compared with the standard diffraction pattern of γ-MnS powder, the ⟨002⟩ oriented long γ-MnS nanorods showed only the (100),(110), (200), and (210) peaks while other diffraction peaks disappeared. This study opened a door for the synthesis of the 1D colloidal nanostructures with pure crystallographic growth direction at large scale, benefiting the manufacture of a novel apparatus based on their anisotropic properties.

Atomic Layer Deposition of Metal Oxides and Chalcogenides for High Performance Transistors

Atomic layer deposition (ALD) is a deposition technique well-suited to produce high-quality thin film materials at the nanoscale for applications in transistors. This review comprehensively describes the latest developments in ALD of metal oxides (MOs) and chalcogenides with tunable bandgaps, compositions, and nanostructures for the fabrication of high-performance field-effect transistors. By ALD various n-type and p-type MOs, including binary and multinary semiconductors, can be deposited and applied as channel materials, transparent electrodes, or electrode interlayers for improving charge-transport and switching properties of transistors. On the other hand, MO insulators by ALD are applied as dielectrics or protecting/encapsulating layers for enhancing device performance and stability. Metal chalcogenide semiconductors and their heterostructures made by ALD have shown great promise as novel building blocks to fabricate single channel or heterojunction materials in transistors. By correlating the device performance to the structural and chemical properties of the ALD materials, clear structure-property relations can be proposed, which can help to design better-performing transistors. Finally, a brief concluding remark on these ALD materials and devices is presented, with insights into upcoming opportunities and challenges for future electronics and integrated applications.

Construction of Various One-Dimensional ZnS/MnS Heteronanostructures with Varied Diameters via the Multistep Solution-Solid-Solid Growth Method

A series of novel one-dimensional (1D) ZnS/MnS heteronanostructures were prepared by a multistep solution-solid-solid (SSS) growth method using [(C₄H₉)₂NCS₂]₂Zn and [(C₄H₉)₂NCS₂]₂Mn as the precursors and Ag₂S as the catalyst. The composition of the 1D heteronanostructures could be effectively modulated by varying the addition sequence of the precursors, such as the Ag₂S/MnS/ZnS and Ag₂S/ZnS/MnS heteronanostructures, which were obtained through the successive addition of [(C₄H₉)₂NCS₂]₂Zn and [(C₄H₉)₂NCS₂]₂Mn precursors but in different sequences. Using the same Ag₂S catalysts, the average diameter of the 1D ZnS/MnS heteronanostructures with multisegments of ZnS and MnS is located between that of ZnS nanorod in Ag₂S/ZnS and that of MnS nanorod in Ag₂S/MnS. This phenomenon could arise from the different cationic radii and lattice parameters of ZnS and MnS. The UV-vis absorbance of the 1D ZnS/MnS heteronanostructures could be attributed to the interband transitions of ZnS and MnS. These findings contribute to the rational synthesis of novel 1D semiconductor heteronanostructures with multicomponents and benefit the development of optoelectronic devices.

Cream roll-inspired advanced MnS/C composite for sodium-ion batteries: encapsulating MnS cream into hollow N,S-co-doped carbon rolls

With advantages of high theoretical capacity and low cost, manganese sulfide (MnS) has become a potential electrode material for sodium-ion batteries (SIBs). However, complicated preparations and limited cycle life still hinder its application. Inspired by cream rolls in our daily life, a MnS/N,S-co-doped carbon tube (MnS/NSCT) composite with a 3D cross-linked tubular structure is prepared via an ultra-simple and low-cost method in this work. As the anode for SIBs, the cream roll-like MnS/NSCT composite has delivered the best electrochemical performance to date (the highest capacity of 550.6 mA h g^-1 at 100 mA g^-1, the highest capacity of 447.0 mA h g^-1 after 1400 cycles at 1000 mA g^-1, and the best rate performance of 319.8 mA h g^-1 at 10 000 mA g^-1). Besides, according to several in situ and ex situ techniques, the sodium storage mechanism of MnS/NSCTs is mainly from a conversion reaction, and the superior electrochemical performance of MnS/NSCTs is mainly attributed to the unique cream roll-like structure. More importantly, this simple method may be feasible for other anode materials, which will greatly promote the development of SIBs.

Coordination-Induced Interlinked Covalent- and Metal-Organic-Framework Hybrids for Enhanced Lithium Storage

Covalent organic frameworks (COF) or metal-organic frameworks have attracted significant attention for various applications due to their intriguing tunable micro/mesopores and composition/functionality control. Herein, a coordination-induced interlinked hybrid of imine-based covalent organic frameworks and Mn-based metal-organic frameworks (COF/Mn-MOF) based on the MnN bond is reported. The effective molecular-level coordination-induced compositing of COF and MOF endows the hybrid with unique flower-like microsphere morphology and superior lithium-storage performances that originate from activated Mn centers and the aromatic benzene ring. In addition, hollow or core-shell MnS trapped in N and S codoped carbon (MnS@NS-C-g and MnS@NS-C-l) are also derived from the COF/Mn-MOF hybrid and they exhibit good lithium-storage properties. The design strategy of COF-MOF hybrid can shed light on the promising hybridization on porous organic framework composites with molecular-level structural adjustment, nano/microsized morphology design, and property optimization.

Synthesis of Thin-Film Metal Pyrites by an Atomic Layer Deposition Approach

Late 3d transition metal disulfides (MS₂ , M=Fe, Co, Ni, Cu, Zn) can crystallize in an interesting cubic-pyrite structure, in which all the metal cations are in a low-spin electronic configuration with progressive increase of the e_g electrons for M=Fe-Zn. These metal pyrite compounds exhibit very diverse and intriguing electrical and magnetic properties, which have stimulated considerable attention for various applications, especially in cutting-edge energy conversion and storage technologies. The synthesis of the metal pyrites is certainly very important, because highly controllable, reproducible, and reliable synthesis methods are virtually essential for both fundamental materials research and practical engineering. In this Concept, a new approach of (plasma-assisted) atomic layer deposition (ALD) to synthesize the thin-film metal pyrites (FeS₂ , CoS₂ , NiS₂ ) is introduced. The ALD synthesis approach allows for atomic-precision control over film composition and thickness, excellent film uniformity and conformality, and superior process reproducibility, and therefore it is of high promise for uniformly conformal metal pyrite thin-film coatings on complex 3D structures in general. Details and implications of this ALD approach are discussed in this Concept, mainly from a conceptual perspective, and it is envisioned that, with this new ALD synthesis approach, a significant amount of new studies will be enabled on both the fundamentals, and novel applications of the metal pyrite materials.

An aminopyridinato Mn(ii) compound as a novel CVD precursor for manganese-containing films

An aminopyridinato Mn(ii) compound as a novel CVD precursor for manganese-containing films.

One-pot synthesis of γ-MnS/reduced graphene oxide with enhanced performance for aqueous asymmetric supercapacitors

In this work, γ-MnS/reduced graphene oxide composites (γ-MnS/rGO) were prepared using a facile one-pot hydrothermal method. As an electrode material for supercapacitors, the γ-MnS/rGO-60 composite obtained under dosages of graphene oxide  was 60 mg and exhibited an enhanced specific capacitance of 547.6 F g^-1 at a current density of 1 A g^-1, and outstanding rate capability (65% capacitance retention at 20 A g^-1), with superior cycling stability and electrochemical reversibility. An asymmetric supercapacitor assembled from γ-MnS/rGO-60 composite and rGO (γ-MnS/rGO-60//rGO) showed a voltage window of 0-1.6 V and delivered a high energy density of 23.1 W h kg^-1 at a power density of 798.8 W kg^-1, and 15.9 W h kg^-1 at 4.5 kW kg^-1. Moreover, two such 1.0 × 1.0 cm² devices connected together in series easily light up a group of LED lights, showing its potential practical application as an attractive energy storage device.

Low-Temperature Atomic Layer Deposition of CuSbS2 for Thin-Film Photovoltaics

Copper antimony sulfide (CuSbS₂) has been gaining traction as an earth-abundant absorber for thin-film photovoltaics given its near ideal band gap for solar energy conversion (∼1.5 eV), large absorption coefficient (>10⁴ cm^-1), and elemental abundance. Through careful in situ analysis of the deposition conditions, a low-temperature route to CuSbS₂ thin films via atomic layer deposition has been developed. After a short (15 min) postprocess anneal at 225 °C, the ALD-grown CuSbS₂ films were crystalline with micron-sized grains, exhibited a band gap of 1.6 eV and an absorption coefficient >10⁴ cm^-1, as well as a hole concentration of 10¹⁵ cm^-3. Finally, the ALD-grown CuSbS₂ films were paired with ALD-grown TiO₂ to form a photovoltaic device. This photovoltaic device architecture represents one of a very limited number of Cd-free CuSbS₂ PV device stacks reported to date, and it is the first to demonstrate an open-circuit voltage on par with CuSbS₂/CdS heterojunction PV devices. While far from optimized, this work demonstrates the potential for ALD-grown CuSbS₂ thin films in environmentally benign photovoltaics.

Tracking Pseudocapacitive Contribution to Superior Energy Storage of MnS Nanoparticles Grown on Carbon Textile

Transition metal chalcogenides have emerged as a new class of electrode materials for energy storage devices with superior electrochemical performance. We have directly synthesized manganese sulfide nanoparticles on carbon textile substrate and used them as electrodes to fabricate flexible all-solid-state supercapacitors. By voltammetry analysis, we have studied the electrochemical properties of MnS-CT composites, which reveal that the Faradaic diffusion-controlled process dominates at low scan rates (82.85% at 5 mV s(-1)) and even at high scan rates (39% at 20 mV s(-1)). The MnS-CT electrode shows high capacitance of 710.6 F g(-1) in LiCl aqueous electrolyte, and the surface redox reactions on MnS nanoparticles are found to be responsible for the high pseudocapacity, which is further analyzed by XRD and HRTEM. Furthermore, MnS-CT supercapacitor exhibits excellent pseudocapacitive performance (465 Fg(-1) at 5 mV s(-1)), excellent stability, light weight (0.83 g as a whole device), and high flexibility. The device has also achieved high energy density and high power density (52 Wh kg(-1) at 308 W kg(-1) and 1233 W kg(-1) with 28 Wh kg(-1), respectively). In practice, three charged supercapacitors in series can power four red light-emitting diodes (LEDs) (2.0 V, 15 mA) for 2 min. All of the evidence shows that MnS nanoparticles combined with carbon textile is a promising electrode material for pseudocapacitors.