2D Nanoplates Research Articles

Interface Engineering Induced Multi-Scale Self-Assembly NiFe-LDH Heterostructures for High-Performance Water Electrolysis.

Confronted with the pressing issue of energy scarcity, the development of an economical and potent bifunctional catalyst is of paramount importance. We adopt an interface engineering strategy to modify the surface of NiFe-LDH nanoplates with O2 plasma treatment. This process enhances the local electric field of NiFe-LDH, resulting in the formation of a self-assembled polycrystalline nanowire array on the nanoplate surface. After O2 plasma treatment for 30 min, the NiFe-LDH-P30 not only formed a heterostructure with rough surface, but also regulated the exposure of crystal surfaces. Due to the strong interface coupling between the self-assembled 3D nanoflowers, 2D nanoplates and 1D nanowires, the NiFe-LDH-P30 exhibits an excellent structural stability. Moreover, it demonstrated exceptional HER and OER activities in alkaline condition, achieving a low overpotentials of 154 mV and 242 mV at 10 mA cm-2, respectively. Furthermore, NiFe-LDH-P30 as the dual-electrode material for the cathode and anode in the process of water splitting results in a low voltage of 1.63 V at a current density of 10 mA cm-2. Through the strategic application of interface engineering, this work has pioneered a novel approach to the creation of transition metal-based electrocatalysts, which is benefit to a range of practical energy applications.

Nanometric-Mapping and In Situ Quantification of Site-specific Photoredox Activities on 2D Nanoplates.

Defective layered bismuth oxychloride (BiOCl) exhibits excellent photocatalytic activities in water purification and environmental remediation. Herein, in situ single-molecule fluorescence microscopy is used to spatially resolve the photocatalytic heterogeneity and quantify the photoredox activities on individual structural features of BiOCl. The BiOCl nanoplates with respective dominant {001} and {010} facets (BOC-001 and BOC-010) are fabricated through tuning the pH of the solution. The corner position of BOC-001 exhibits the highest photo-oxidation turnover rate of 262.7 ± 30.8s-1µm-2, which is 2.1 and 65.7 times of those of edges and basal planes, respectively. A similar trend is also observed on BOC-010, which can be explained by the heterogeneous distribution of defects at each structure. Besides, BOC-001 shows a higher photoredox activity than BOC-010 at corners and edges. This can be attributed to the superior charge separation ability, active high-index facets of BOC-001, and its co-exposure of anisotropic facets steering the charge flow. Therefore, this work provides an effective strategy to understand the facet-dependent properties of single-crystalline materials at nanometer resolution. The quantification of site-specific photoredox activities on BiOCl nanoplates sheds more light on the design and optimization of 2D materials at the single-molecule level.

Transformation of ZnS microspheres to non-centrosymmetric nanoplates for the fabrication of flexible piezoelectric nanogenerators: Electrode surface area modification for boosting the output performance

We report the transformation of ZnS particles from microsphere to 2D nanoplate having a non-centrosymmetric phase by optimizing growth parameters of hydrothermal method, and fabrication of flexible piezoelectric nanogenerators (PENGs). ZnS nanoplates-based PENG showed maximum open circuit voltage and short circuit current of ∼ 3.8 V and 1.8 μA, respectively. Thereafter, surface of aluminium (Al) electrode was modified by making parallel and cross-parallel lines using a cost-effective technique. Surface-modified Al-electrode-based PENG device generated ∼ 6.6 and 2.5 times higher open circuit voltage and short circuit current, respectively, with a power density of ∼ 41.5 μWcm−2. This device was successfully used as portable electronics by flashing 15 red LEDs after charging a 1 μF capacitor up to 7.1 V in 75 s. Furthermore, the device exhibited noticeable electric output signals under various kinds of human body motions, which makes it a promising candidate for self-powered wearable sensor applications.

Diammonium cation pre-intercalation into inorganic framework for efficient Dion-Jacobson perovskite solar cells

The two-dimensional and three-dimensional (2D/3D) perovskite heterojunction has garnered significant attention in perovskite solar cells (PSCs) owing to the superior stability, modified band alignment and suppressed defects. Here, a pre-intercalation strategy involving bulky cations into inorganic framework to construct a buried 2D/3D perovskite heterojunction is proposed. The incorporation of bulky cation into PbI2 not only leads to the formation of well-oriented 2D nanoplates, but also disrupts the compact inorganic structure. It results in substantially increased grain boundaries at the buried interface, facilitating the complete reaction with small cations. Additionally, the pre-intercalated bulky cation acts as a template for the oriented growth of perovskite layer, leading to significantly reduced defects, enlarged crystal size and enhanced orientation. Furthermore, the advanced formation of buried 2D phases constructs a bottom-up 2D/3D perovskite heterojunction, enhancing carrier extraction and reducing energy loss in the PSCs. The resulting PSC achieves a champion power conversion efficiency of 23.40 %, surpassing the control device of 20.64 %. Moreover, the PSC maintains 88 % of its initial efficiency after 1050 h continuous efficiency tracking and retains over 97 % of its performance for 2232 h under a low humidity condition. Therefore, the pre-intercalation strategy represents a promising approach for both efficiency and stability challenges in PSCs.

Two-dimensional Cs3Sb2Br9 inducing transformation of three-dimensional CsPbBr3 to nanoplates.

This communication describes an effective morphological control strategy involving introducing two-dimensional (2D) Cs3Sb2Br9 to induce a transformation of three-dimensional (3D) CsPbBr3 to 2D nanoplates (NPLs). By tuning the Sb/Pb ratio, 2D CsPbBr3 NPLs exhibiting a deep-blue emission centered at a wavelength of 464 nm with an FWHM of 24 nm have been produced. The absence of organic ligands in these high-quality 2D NPLs mitigate the instability issue induced by organic ligand migration and penetration, and these NPLs exhibit 80% of the initial PL intensity after 55 days.

Controllable synthesis of sodium-calcium silicate nanoplates and the enhancement of cement-based materials

Special planar structure endows two-dimensional (2D) materials with unique physical and chemical properties and the application of 2D materials to cement-based materials ensures the mechanical properties of buildings and infrastructures. Herein, a novel 2D nanoplate is synthesized through hydrothermal method with controlled sizes and morphologies. TEM and SEM measurements are used to characterize the nanostructures, confirming the morphologies, the distribution of elements among the structures and the crystal structure. The as-prepared nanoplates are able to enhance the mechanical strength of the cement mortar by its specific morphology and pozzolanic activity. The flexural strength was improved by 45.73 % after 1 d curing due to the acceleration of cement hydration. From the analysis of XRD and TG-DTG patterns, the nanoplates have strong interaction with the cement paste and the amount of the hydration products varied by the addition of the nanoplates. This approach helps promote the development of cement-based materials with high performance.

Different shape-controlled synthesis and catalytic property studies on bismuth nanomaterials

Bi with four different morphologies (zero-dimensional (0D) nanoparticles, one-dimensional (1D) nanowires, two-dimensional (2D) nanoplates, and three-dimensional (3D) shuttle like structures) was successfully synthesized by changing the synthetic conditions. The Bi nanostructures were characterized in terms of structure, morphology, surface characteristics, optical properties and catalytic activity using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET), photoluminescence (PL), UV–vis absorption spectroscopy (UV–Vis) and total organic carbon (TOC) analyzer techniques, respectively. The PL spectra is shown that the reduction of the size of Bi nanomaterials can reduce the recombination rate of photoelectrons and holes, which leads to the effective separation of photocharge carriers and the lowest photoelectron and hole recombination rates. The band gap values of Bi nanoparticles, nanowires, nanoplates and shuttle like structures are 2.71 eV, 2.76 eV, 2.92 eV and 3.22 eV respectively, favouring the harvesting of visible-light. The experimental results of the degradation performance of Bi with different morphologies exhibited that 99.9%, 97.9%, 96.2% and 74.4% degradations of the Rhodamine B (Rh B) was observed for Bi nanoparticles, nanowires, nanoplates and shuttle like structures, respectively. During the degradation of RhB, with the prolongation of treatment time to 90 min, the highest removal rates of chemical oxygen demand (COD) and TOC was 73.5% and 68.4%, respectively. According to TOC analysis, more than 68% of the carbon in the dyes will produce CO2 products. The removal efficiency is attributed to the production of ·O2−, ·OH and h+ and their mineralization to RhB. At the same time, the achieved results also reveal that Bi2O3 and BiOCl was found in Bi surfaces before and after catalytic degradation, which was confirmed by XPS and FTIR technology. In addition, Bi with the same morphology performed different catalytic activities in Rh B solution with different pH values. It was found that the degradation efficiency increased evidently when the pH value decreased. The mechanism of Bi photocatalytic activity was proposed based on the results of product analysis, radical capture and XPS analysis.

Fabrication of BiCuOS nanoflowers acting as nanoarrays on photonic nanoparticles for chemo-photothermal therapy

In recent years, 3D flower shaped nanostructures with an ability to improve internal photo reflections and absorptions is gaining popularity for the development of photo-thermal heat generating materials for cancer therapy. The use of bimetallic oxysulfide materials as photo-thermal agent is especially interesting as it is not only resulting in heat generation by absorbing laser light in the biological window but also participates in reactive oxygen species generation in tumor environment. In this work, we have reported a novel flower shaped BiCuOS nanostructures made of CuS base structures with vertical nanoarrays of bismuth oxide nanoplates for synergistic chemo-photothermal cancer therapy. Notably, 2D nanoplates (∼150 ± 50 nm in length and thickness of about ∼25 nm) could be seen grown in the form of nanoflowers (NFs) of 800 ± 100 nm in size on CuS base structures. The electronic structure, density of states, bond angle, bond length and thermal stability of formed NFs were investigated by density functional theory and molecular dynamic studies. The photo-thermal conversion efficiency was increased as a function of NF concentration. The percentage of doxorubicin released was estimated to be only ∼4% even after one day of incubation at pH 7.4 which increased to 38 and 45% at pH 5.5 without and with near infra-red light exposure, respectively. The cell viability experiments with fibroblast cells and red blood cells exhibited excellent biocompatibility of BiCuOS NFs. The synthesized BiCuOS NFs showed excellent anticancer activity against Hep-2 cells. Hence, the BiCuOS NFs reported here have huge potential for use as novel dual performing chemo-and-photothermal agent for advanced cancer therapy.

Magnetocaloric properties of shape-dependent nanostructured Gd2O3 oxide particles

Single-phase Gd2O3 nanostructures with different morphologies, such as nanoparticles, nanorods, nanospheres, and nanoplates, were synthesised. Gd2O3 1D nanorods and 2D nanoplate architectures were prepared via the hydrothermal method, while 3D hollow nanospheres were synthesised via homogeneous precipitation. The magnetic and magnetocaloric properties of Gd2O3 nanostructured particles were studied as functions of temperature and field. The material demonstrated typical paramagnetic behaviour in the measured temperature range of 3–300 K. The magnetic entropy change (−ΔS M ) was determined from the magnetic isotherms measured in the 3–38 K temperature range in the field up to 5 T. The maximum change in magnetic entropy value 11.2 J kg−1 K−1 for the nanoplate, 9.4 J kg−1 K−1 for the nanorod, 9.2 J kg−1 K−1 for the nanosphere, and 10.7 J kg−1 K−1 for the nanoparticle sample was observed at temperature 5 K for the magnetic field of 5 T. Owing to large these Gd2O3 nanostructured particles would be considered promising materials for magnetic refrigeration at cryogenic temperatures.

High Thermoelectric Performance in 2D Sb2Te3 and Bi2Te3 Nanoplate Composites Enabled by Energy Carrier Filtering and Low Thermal Conductivity.

Thermoelectrics are an important class of materials with great potential in alternative energy applications. In this study, two-dimensional (2D) nanoplates of the layered chalcogenides, Sb2Te3 and Bi2Te3, are synthesized and composites of the two are investigated for their thermoelectric properties. The two materials, Sb2Te3 and Bi2Te3, were synthesized as hexagonal, 2D nanoplates via a colloidal polyol route. The as-synthesized Sb2Te3 and Bi2Te3 vary drastically from one another in their lateral and vertical dimensions as revealed by scanning electron microscopy and atomic force microscopy. The single crystalline nanoplate nature is deduced by high-resolution transmission electron microscopy and selected area electron diffraction. Nanoplates have well-defined hexagonal facets as seen in the scanning and transmission electron microscopy images. The nanoplates were consolidated as an anisotropic nanostructured pellet via spark plasma sintering. Preferred orientation observed in the powder X-ray diffraction pattern and scanning electron microscopy images of the fractured pellets confirm the anisotropic structure of the nanoplates. Thermoelectric properties in the parallel and perpendicular directions were measured, revealing strong anisotropy with a significant reduction to thermal conductivity in the perpendicular direction due to increased phonon scattering at nanoplate interfaces. All compositions, except that of the 25% Bi2Te3 nanoplate composite, behave as degenerate semiconductors with increasing electrical resistivity as the temperature increases. The Seebeck coefficient is also increased dramatically in the nanocomposites, the highest reaching 210 μV/K for 15% Bi2Te3. The increase in Seebeck is attributed to energy carrier filtering at the nanoplate interfaces. Overall, these enhanced thermoelectric properties lead to a drastic increase in the thermoelectric performance in the perpendicular direction, with zT ∼ 1.26, for the 15% Bi2Te3 nanoplate composite at 450 K.

Studies on the optical stability of CsPbBr3 with different dimensions (0D, 1D, 2D, 3D) under thermal environments.

The thermal stability of phosphor materials had long been a bottleneck in their commercialization. Nowadays, cesium lead halide perovskite CsPbBr3 has been considered a potential replacement for the next generation of optoelectronic devices due to its excellent optical and electronic properties, however, the devices inevitably generate high temperatures on the surface under prolonged energization conditions in practical applications, which can be fatal to CsPbBr3. Despite the various strategies that have been employed to improve the thermal stability of CsPbBr3, systematic studies of the thermal stability of the basis CsPbBr3 are lacking. In this study, CsPbBr3 with different dimensions (0D quantum dots (QDs), 1D nanowires (NWs), 2D nanoplate (NPs), 3D micron crystals (MCs)) was prepared by traditional high-temperature thermal injection, and a systematic study was carried out on their optical properties and thermal stability. The results revealed that the dimensional change will directly influence the optical properties as well as the thermal stability of CsPbBr3. In particular, 3D CsPbBr3 MCs maintained relatively high thermal stability under high-temperature environments, which will bring interest for the commercialization of next-generation perovskite optoelectronic devices.

Spinel-structured CuCo2O4 with a mixed 1D/2D morphology for asymmetric supercapacitor and oxygen evolution electrocatalyst applications

Transition metal oxides with multifunctional properties have attracted attention for use in various electro-catalytic applications, but their weak electroactive centers have severely limited their commercialization. In the present study, we describe an efficient bifunctional material whose structural morphology makes it both an effective oxygen evolution reaction (OER) electrocatalyst and a reliable power source for supercapacitor (SC) electrodes. We successfully fabricated spinel-structured CuCo2O4 consisting of a mix of one-dimensional (1D) nanorods and two-dimensional (2D) nanoplates using precipitation followed by hydrothermal treatment and calcination. For comparison purposes, CuO nanoplates and Co3O4 nanorods were synthesized individually, and their multifunctional features were examined. The synthesized mixed-morphology CuCo2O4 delivered an excellent electrochemical performance for SC and OER electrocatalyst applications. The mixed-morphology CuCo2O4 produced a specific capacity of 561 C g−1 (1122 F g−1) at 1 A g−1 and exhibited a superior rate capability and excellent stability, with 92% retention of capacity after 5000 cycles at 30 A g−1 in a three-electrode cell. In addition, a fabricated asymmetric supercapacitor device (CuCo2O4//activated carbon) delivered an energy density of 47.6 W h kg−1 and a power density of 1280 W kg−1, with outstanding long-term cyclic stability. Furthermore, the prepared CuCo2O4 had a low Tafel slope, a high electrochemical surface area, and excellent long-term durability. Therefore, mixed-morphology CuCo2O4 holds significant promise for use in SC and OER catalyst applications. Moreover, this study offers a useful method for preparing multifunctional materials.

Phosphine free synthesis of copper telluride nanocrystals in 1D and 2D shapes using Dipehylditelluride (DPDTe) as an air-stable source

In this paper, we have developed a ‘phosphine-free’ method for synthesising copper telluride nanocrystals using diphenyl ditelluride as an air-stable tellurium source. The diphenyl ditelluride is shown to have optimal reactivity for the colloidal synthesis of Cu2Te, allowing optimal control over the phase and morphology. Using this unexplored Te precursor for copper telluride synthesis, 1D nanorods of hexagonal phase (Cu2Te) were synthesised at a moderate temperature of 180 °C. The precise control over key parameters for this system results in Cu2−x Te nanocrystals forming with varied shapes (1D nanorods and 2D nanoplates), sizes, and crystal phases (hexagonal Cu2Te and orthorhombic Cu1.43Te).

Soft crystal lattice and large anharmonicity facilitate the self-trapped excitonic emission in ultrathin 2D nanoplates of RbPb2Br5.

Self-trapping of excitons (STE) and concomitant useful broadband emission in low-dimensional metal halides occur due to strong electron–phonon coupling, which exhibit potential applications in optoelectronics and solid-state lighting. Lattice softness and high anharmonicity in the low-dimensional structure can lead to transient structural distortion upon photoexcitation that should promote the spatial localization or trapping of charge carriers, which is essential for STE. Herein, we report the ligand-assisted reprecipitation synthesis of ultrathin (∼3.5 nm) two-dimensional (2D) metal halide, RbPb2Br5 nanoplates (NPLs), which demonstrate highly Stokes shifted and broadband emission covering most parts of the visible to near IR range (500–850 nm) with a long-lived photoluminescence (PL) lifetime. The excitation wavelength independent emission and emission wavelength independent excitation spectra along with the analogous PL decay kinetics of bulk and NPLs suggest the intrinsic nature of broadband emission. The experimental low sound velocity (∼1090 m s−1) and associated low bulk and shear moduli (10.10 and 5.51 GPa, respectively) indicate the large anharmonicity and significantly soft lattice structure, which trigger the broadband STE emission in 2D NPLs of RbPb2Br5. Strong electron-longitudinal optical (LO) phonon coupling results in broadband STE emission in 2D RbPb2Br5 NPLs.

Nickel Cobaltite Nanoplate-Based Electrochemical Sensing Platform from Printable Inks for Simultaneous Detection of Dopamine and Uric Acid.

2D metal oxide-based nanomaterials have emerged as an exciting area of research owing to their rich electrochemical properties and diverse applications, including biosensors. In this work, we have synthesized ultra-thin Co3 O4 , NiO, and NiCo2 O4 nanostructures supported on a carbon cloth and printed graphite/Kapton substrates following thermal reduction of self-assembled metal alkanethiolates. These nanostructures act as a sensing platform for simultaneous detection of dopamine (DA) and uric acid (UA), important biological molecules in physiological and pathological tests. The ultrathin 2D nanoplates of NiCo2 O4 spinel formed in this study exhibit high electrochemical activity than pristine NiO and Co3 O4 . The electrochemical characterization studies indicate that NiCo2 O4 possesses a high potential for DA and UA with a peak separation of ∼140 mV, high sensitivity, and excellent selectivity. The low-cost and disposable, single-shot probe biosensors fabricated in this work possess a wide working range of 0.001-1000 μM with detection limits of 0.33 and 0.49 nM for DA and UA, respectively, with a practically achievable limit of quantification of ∼1 nM. Multiple sensing electrodes are printed on graphite/Kapton all at once following this method with improved reproducibility for DA and UA sensing further extending the scope of work towards mass fabrication and practical usage.

Low-Dimensional Nanostructure Based Flexible Photodetectors: Device Configuration, Functional Design, Integration, and Applications

ConspectusA flexible photodetector that extends unique capabilities such as deformation, adaptivity to a soft surface, mechanical stability, and high photoresponsivity compared to the rigid devices has come to prominence in telecommunication, remote sensing, medical diagnostics, image sensing, optical communication, and the biomimetic human visual system. Low-dimensional nanomaterials consisting of one-dimensional (1D) nanowires (NWs), 2D nanoplates, and heterojunctions such as quantum dot modified NWs, hierarchical 1D hybrid nanomaterials, 1D/2D composites, 2D/2D heterostructures, etc. are considered as promising photosensitive materials in designing a flexible photodetector owing to the large surface to volume ratio and mechanical suppleness along the growth direction of the 1D NWs, excellent mechanical strength, superior structural stability, fast electron mobility, and low power dissipation of 2D nanoplates, and the synergistic effect of the heterojunctions.In this Account, we present our recent progress on low-dimensional nanostructure based flexible photodetectors. First, the three components, including the soft substrate, conductive electrodes, and representative low-dimensional nanomaterials (1D NWs, 2D nanoplates, and various types of heterojunctions) required for achieving flexible photodetector are summarized. Then, the design strategies toward functional photodetectors are presented in terms of their flexibility, stretchability, transparency, and photodetector with tunable photoresponse properties. The integration concepts of the photodetector with flexible energy storage to realize independent detectivity and the field effect transistor to amplify the responsivity are also provided. Furthermore, the application examples of the flexible photodetector in the artificial visual memory system and the biomimetic eye are reviewed. Finally, we discuss the future prospects of the low-dimensional nanostructure based flexible photodetector in the field of flexible image sensing and integrated electronics.

Synthesis of 2D-CZTS nanoplate as photocathode material for efficient PEC water splitting

Fabrication of economically feasible photocathode for hydrogen energy production through solar water splitting is a major research among the scientific community for a decade. P-type compound Cu2ZnSnS4 (CZTS) is very interesting material due to its absorption property, earth-abundant constituents and environmental friendliness that serves as a suitable candidate to act as a photocathode. In the present work, Cu2ZnSnS4 (CZTS) nanoparticles are synthesized by simple one-step chemical method and annealed at 350 °C for three different times (60 min, 90 min, and 120 min). The effect of annealing time on the structural, optical and photoelectrochemical properties are investigated. XRD pattern indicates the formation of tetragonal crystal structure and the crystallinity increases according to the annealing time. 2D nanoplate morphology is obtained for the sample that was annealed for 120 min. From the absorption spectra, it was found that the bandgap decreases with increase of annealing time. Further, the prepared nanoparticle thin films are used as a cathode for photoelectrochemical water splitting application. Among these, the nanoparticles that are annealed for 120 min showed higher photocurrent density when compared to nanoparticles annealed for 60 min and 90 min.

Scalable Production of Nickel Cobaltite Nanoplates using Solution-Processed Inks for OER Electrocatalysis

The large-scale fabrication of non-precious metal oxide electrocatalysts with reasonable control over catalytic active surface sites is critical for oxygen evolution reaction (OER). Herein, we report an industrially scalable, dip-coating method for the fabrication of 3D electrodes using Co and Ni thiolate hybrid inks. The solventless thermolysis of Co hexadecane thiolate in Ni butane thiolate (4:1) mixture results in 2D nanoplates of Ni-Co oxide (NCO) with spinel structure and superparamagnetic nature. The NCO acts as an electrocatalyst exhibiting excellent OER performance in alkaline media with low overpotential values of 310 mV and long-term stability. XPS studies reveal that Ni3+ and Co3+ species on the surface of NCO-20 nanoplates enhance the OER activity. The superparamagnetic NCO-20 shows enhancement in OER with the external magnetic field due to electron spin polarization. Thus, the present study is of high technological potential in OER performance and possible commercialization due to scalable production.

Hybrid 3D Nanostructure-Based Hole Transport Layer for Highly Efficient Inverted Perovskite Solar Cells.

In this study, we demonstrate a new hybrid three-dimensional (3D) nanostructure system as an efficient hole transport layer (HTL) by a facile design of a low-temperature solution process. It is realized by integrating high-conductive chromium-doped CuGaO2 nanoplates synthesized with choline chloride (denoted as Cr/CuGaO2-CC) into ultrasmall NiOx nanoparticles. First, we propose to incorporate a Cr-doped strategy under hydrothermal synthesis conditions together with controllable intermediates and surfactants' assistance to synthesize fine-sized Cr/CuGaO2-CC nanoplates. Subsequently, these two-dimensional (2D) nanoplates serve as the expressway for improving hole transportation/extraction properties. Meanwhile, the ultrasmall-sized NiOx nanoparticles are employed to modify the surface for achieving unique surface properties. The HTL formed from the designed hybrid 3D-nanostructured system exhibits the advantages of smooth and full-covered surface, remarkable charge collection efficiency, energy level alignment between the electrode and perovskite layer, and the promotion of perovskite crystal growth. Consequently, nearly 20% of power conversion efficiency with negligible hysteresis is achieved in inverted perovskite solar cells (PSCs). This work not only demonstrates the potential applications of a 3D-nanostructured Cr/CuGaO2-CC/NiOx hybrid HTL in PSCs but also provides a fundamental insight into the design of hybrid material systems by manipulating electric behavior and morphology structure for achieving high-performance photovoltaic devices.

Co3S4 Nanoplate Arrays Decorated with Oxygen-Deficient CeO2 Nanoparticles for Supercapacitor Applications

Cobalt sulfide is favorable for supercapacitors, but its application is inhibited by the inherent slow charge transfer kinetics and poor stability in alkaline solution. Herein, zeolitic imidazole framework (ZIF)-derived Co3S4 nanoplate arrays (NPAs) decorated with CeO2 nanoparticles (NPs) grown on Ni foam have been developed. The obtained Co3S4/CeO2-NPAs display a 2D leaf-like nanoplate morphology (average thickness of nearly 230 nm) with a large amount of oxygen vacancies and exhibits remarkably boosted specific capacity/capacitance, i.e., 1155.8 C/g (2408 F/g) at 0.5 A/g with a notable rate capability (76.5% at 10 A/g), compared to Co3S4-NPAs or CeO2 NPs. More importantly, a two-electrode cell comprising the Co3S4/CeO2-NPAs and an activated carbon electrode displays a high energy density of 45.4 Wh/kg (at a power density of 850 W/kg) with decent long-term durability. Furthermore, a red light-emitting diode can be lighted up for 10 min by two charged cells, showing great prospect of Co3S4/CeO2-NPAs. The outstanding electrochemical properties of the Co3S4/CeO2-NPAs are mainly attributed to the 2D nanoplate morphology with much accessible active sites and the introduction of CeO2 NPs. The Co3S4/CeO2-rich interfaces promote electron transfer between Co3S4 and CeO2. The abundant oxygen vacancies adhere to the surface of Co3S4 and can enhance the electronic conductivity and the capture of OH–. In addition, the CeO2 layer can protect the Co3S4-NPAs from corrosion by the KOH electrolyte during the electrochemical process. Therefore, the electrode developed by this work has great potential in electrochemical applications.