Four-State Electrochromism in Tris(4-aminophenyl)amine- terephthalaldehyde-based Covalent Organic Framework.

Covalent organic frameworks (COFs) are of massive interest due to their potential application spanning diverse fields such as gas storage and separation, catalysis, drug delivery systems, sensing, and organic electronics. In view of their application-oriented quest, the field of electrochromism marked a significant stride with the reporting of the first electrochromic COF in 2019 [J. Am.

Investigating solvent effects on synthesizing novel cobalt hydroxide and fluoride complex from Co(BF) as active materials of the battery supercapacitor hybrid.

Metal-organic framework (MOF) derivatives with tunable pore structure and improved conductivity are intensively designed as electroactive materials. Incorporating structure directing agents (SDA) is beneficial for designing MOF derivatives with excellent electrochemical performances. Ammonium fluoroborate has been reported as an effective SDA, coupled with cobalt salt and 2-methylimidazole, to synthesize zeolitic imidazolate framework-67 (ZIF-67) derivatives for charge storage.

-CoOTe ( = S, Se, and P) with Oxygen/Tellurium Dual Vacancies and Banana Stem Fiber-Derived Carbon Fiber s Battery-Type Cathode and Anode Materials for Asymmetric Supercapacitor.

In this work, we demonstrated the synthesis of anions (X = selenium (Se), sulfur (S), and phosphorus (P)) doped cobalt oxytelluride (X-CoOTe) with oxygen and tellurium dual vacancies using hydrothermal methods, followed by selenization, sulfurization, and phosphorization reactions. Especially, the Se-CoOTe-modified nickel foam (Se-CoOTe/NF) electrode delivered a higher specific capacity (752.95 C/g) and an extremely lower charge transfer resistance (0.

Demonstration of a Gel-Polymer Electrolyte-Based Electrochromic Device Outperforming Its Solution-Type Counterpart in All Merits: Architectural Benefits of CeO Quantum Dot and Nanorods.

For years, solution-type electrochromic devices (ECDs) have intrigued researchers' interest and eventually rendered themselves into commercialization. Regrettably, challenges such as electrolyte leakage, high flammability, and complicated edge-encapsulation processes limit their practical utilization, hence necessitating an efficient alternate. In this quest, although the concept of solid/gel-polymer electrolyte (SPE/GPE)-based ECDs settled some issues of solution-type ECDs, an array of problems like high operating voltage, sluggish response time, and poor cycling stability have paralyzed their commercial applicability.

Multifunctional Structure-Modified Quaternary Compounds CoSe-CuSe-WSe Mixed with MWCNT as a Counter Electrode Material for Dye-Sensitized Solar Cells.

In this study, a trimetallic selenide material with a hollow spherical structure (CoSe-CuSe-WSe) was synthesized through two consecutive solvothermal reactions. The synergistic effect between the quaternary elements, the benefits of the selenization of metals, and the unique morphology led to the prominent electrocatalytic ability of CoSe-CuSe-WSe hollow spheres. CoSe-CuSe-WSe hollow spheres were then mixed with oxygen plasma-treated multiwalled carbon nanotubes (MWCNT) as counter electrode (CE) material for dye-sensitized solar cells (DSSCs), achieving a photoelectric conversion efficiency (η) of 9.

Morphological Features of SiO Nanofillers Address Poor Stability Issue in Gel Polymer Electrolyte-Based Electrochromic Devices.

Nanofillers' applicability in gel polymer electrolyte (GPE)-based devices skyrocketed in the last decade as soon as their remarkable benefits were realized. However, their applicability in GPE-based electrochromic devices (ECDs) has hardly seen any development due to challenges such as optical inhomogeneity brought by incompetent nanofiller sizes, transmittance drop due to higher filler loading (usually required), and poor methodologies of electrolyte fabrication. To address such issues, herein, we demonstrate a reinforced polymer electrolyte tailored through poly(vinylidene fluoride--hexafluoropropylene) (PVDF-HFP),1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF), and four types of mesoporous SiO nanofillers, porous (distinct morphologies) and nonporous, two each.

Nanoflower-like P-doped Nickel Oxide as a Catalytic Counter Electrode for Dye-Sensitized Solar Cells.

Flower-like phosphorus-doped nickel oxide (P-NiO) is proposed as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). The flower-like nickel oxide essentially serves as the matrix for the CE, which is expected to promote a two-dimensional electron transport pathway. The phosphorus is intended to improve the catalytic ability by creating more active sites in the NiO for the catalysis of triiodide ions (I) to iodide ions (I) on the surface of the CE.

Introducing Postmetalation Metal-Organic Framework to Control Perovskite Crystal Growth for Efficient Perovskite Solar Cells.

A novel lead-containing metal-organic framework (Pb-MOF) is synthesized through postmetalation of MOF-525. Postmetalation renders lead ions bound with the organic linker of MOF-525, which can serve as nucleation points to promote perovskite crystallization. The introduction of lead postmetalated MOF-525 (Pb-MOF) as a scaffold layer between compact TiO (c-TiO) layer and perovskite layer promotes perovskite crystal growth in enlarging crystal grain size with better crystallinity, hence decreasing defect sites in the perovskite layer.

Orientation-Adjustable Metal-Organic Framework Nanorods for Efficient Oxygen Evolution Reaction.

A series of orientation-adjustable metal-organic framework (MOF) nanorods, CoFe(dobpdc)-I to CoFe(dobpdc)-III (dobpdc = 4,4'-dihydroxybiphenyl-3,3'-dicarboxylate), is developed on a 3D nickel foam (NF) template. By modulating the solvent composition for synthesis, the feature of MOF nanorods on the template can be varied from disorganized to a unidirectional orientation perpendicular to the NF. Well-aligned, vertically oriented CoFe(dobpdc)-III nanorods are hydrophilic and have more exposed active sites and interfacial charge transfer ability.

Additive Engineering by Bifunctional Guanidine Sulfamate for Highly Efficient and Stable Perovskites Solar Cells.

High efficiency and good stability are the challenges for perovskite solar cells (PSCs) toward commercialization. However, the intrinsic high defect density and internal nonradiative recombination of perovskite (PVK) limit its development. In this work, a facile additive strategy is devised by introducing bifunctional guanidine sulfamate (GuaSM; CH N , Gua ; H N-SO , SM ) into PVK.

Transparent Cobalt Selenide/Graphene Counter Electrode for Efficient Dye-Sensitized Solar Cells with Co/-Based Redox Couple.

In this study, we demonstrate a facile, one-pot, and low-temperature (∼85 °C) chemical bath method for the preparation of a composite of cobalt selenide/graphene (CoSe/Gr) as the electrocatalyst for the counter electrode (CE) of dye-sensitized solar cells (DSSCs) with a cobalt-based electrolyte. The CoSe/Gr composite film was envisaged to have the advantages of both components, that is, the high electrochemical surface area of CoSe and the straight paths for electron transfer from Gr. The DSSCs with CoSe/Gr exhibited a power conversion efficiency (η) of 11.

Oxygen Plasma Activation of Carbon Nanotubes-Interconnected Prussian Blue Analogue for Oxygen Evolution Reaction.

To obtain renewable and clean fuels, exploration of effective electrocatalysts is highly desirable due to the sluggish kinetics of water splitting. In this study, the oxygen plasma-activated hybrid structure of Ni-Fe Prussian blue analogue (PBA) interconnected by carbon nanotubes (O-CNT/NiFe) is reported as a highly effective electrocatalytic material for the oxygen evolution reaction (OER). The electrocatalytic performance is significantly influenced by different mass ratios of CNTs to Ni-Fe PBA.

Cobalt-tungsten diselenide-supported nickel foam as a battery-type positive electrode for an asymmetric supercapacitor device: comparison with various MWSe (M = Ni, Cu, Zn, and Mn) on the structural and capacitance characteristics.

New exploration in nanomaterial research has been greatly encouraged so as to discover active electrode materials with extraordinary properties and performances. In this report, we demonstrated the synthesis of different transition metal-incorporated MWSe2 (M = Co, Ni, Cu, Zn, and Mn) and studied them using various characterization techniques. Subsequently, the proposed bimetallic chalcogenides were successfully applied as the active electrode materials for pseudocapacitor applications.

Stoichiometry-Controlled MoWTe Nanowhiskers: A Novel Electrocatalyst for Pt-Free Dye-Sensitized Solar Cells.

Novel polymorphic MoWTe-based counter electrodes possess high carrier mobility, phase-dependent lattice distortion, and surface charge density wave to boost the charge-transfer kinetics and electrocatalytic activity in dye-sensitized solar cells (DSSCs). Here, we report the syntheses of stoichiometry-controlled binary and ternary MoWTe nanowhiskers directly on carbon cloth (CC), denoted by MoWTe/CC, with an atmospheric chemical vapor deposition technique. The synthesized MoWTe/CC samples, including -MoTe/CC, WTe/CC, MoWTe/CC, and & -MoWTe/CC, were then employed as different counter electrodes to study their electrochemical activities and efficiencies in DSSCs.

Asymmetric Benzotrithiophene-Based Hole Transporting Materials Provide High-Efficiency Perovskite Solar Cells.

In this study, we synthesized a series of small-molecule benzotrithiophenes (BTTs) and used them as hole transporting materials (HTMs) in perovskite solar cells (PSCs). The asymmetric benzo[2,1-:-3,4-':5,6-″]trithiophene unit was used as the central core to which were appended various donor groups, namely, carbazole (BTT-CB), thieno thiophene (BTT-FT), triphenylamine (BTT-TPA), and bithiophene (BTT-TT). The extended aromatic core in the asymmetric BTT provided full planarity, thereby favoring intermolecular π-stacking and charge transport.

Thioalkyl-Functionalized Bithiophene (SBT)-Based Organic Sensitizers for High-Performance Dye-Sensitized Solar Cells.

A series of 3,3'-dithioalkyl-2,2'-bithiophene (SBT)-based organic chromophores were designed and developed for the use in dye-sensitized solar cells (DSSCs). By appropriate structural modification of the SBT π-linkers with different alkyl chains and conjugated thiophene units, chromophore aggregation and interfacial charge recombination could be suppressed to a remarkable degree. Single-crystal and optical/electrochemical data clearly show that the SBT core is nearly planar with the torsional angle <1°, likely via S(alkyl)···S(thiophene) intramolecular locks.

Enhanced Near-Infrared Photoresponse of Inverted Perovskite Solar Cells Through Rational Design of Bulk-Heterojunction Electron-Transporting Layers.

How to extend the photoresponse of perovskite solar cells (PVSCs) to the region of near-infrared (NIR)/infrared light has become an appealing research subject in this field since it can better harness the solar irradiation. Herein, the typical fullerene electron-transporting layer (ETL) of an inverted PVSC is systematically engineered to enhance device's NIR photoresponse. A low bandgap nonfullerene acceptor (NFA) is incorporated into the fullerene ETL aiming to intercept the NIR light passing through the device.

Electrochemical sensing of anti-inflammatory agent in paramedical sample based on FeMoSe modified SPCE: Comparison of various preparation methods and morphological effects.

We demonstrate the different types of synthesis processes (hydrothermal, microwave and simple chemical synthesis) to prepare the Fe doped molybdenum diselenides (H-FeMoSe, M-FeMoSe, and C-FeMoSe) and investigate their relevant electrocatalytic activities. The Fe doped MoSe exhibited an enhanced charge transfer conductivity and electrocatalytic activity. Especially, the H-FeMoSe with vertically aligned structures facilitate the abundant exposed active edge sites.

A Pt-free pristine monolithic carbon aerogel counter electrode for dye-sensitized solar cells: up to 20% under dim light illumination.

In this work, pristine carbon aerogels (CAs) were used as Pt-free counter electrodes (CEs) in dye-sensitized solar cells (DSSCs) by varying the molar ratio of their precursors. Pristine mesoporous CAs with controlled resorcinol (R)/formaldehyde (F) and resorcinol (R)/sodium carbonate (C) molar ratios were successfully prepared. The as-prepared CAs were synthesized via a polymeric sol-gel reaction and were labeled as CA-O, CA-Q, CA-F, CA-C, and CA-G.

Active-Site-Rich 1T-Phase CoMoSe Integrated Graphene Oxide Nanocomposite as an Efficient Electrocatalyst for Electrochemical Sensor and Energy Storage Applications.

The presence of defect/distortion on layered structure of metal chalcogenides facilitate the higher electronic conductivity and electrocatalytic activity. In this work, we have successfully synthesized Co-doped MoSe(CoMoSe, CoMoSe, CoMoSe, and CoMoSe) in 1T phase crystal structure by using hydrothermal technique and integrated with graphene oxide (GO). Various analytical techniques such as TEM, STEM, FESEM, XRD, RAMAN, EDX, ICP, and XPS confirmed the formation of 1T phase and defective sites on Co-doped MoSe.

Synthesis of Surfactant-Free and Morphology-Controllable Vanadium Diselenide for Efficient Counter Electrodes in Dye-Sensitized Solar Cells.

In this study, a transition-metal selenide, vanadium diselenide (VSe), with various morphologies was synthesized by employing a surfactant-free hydrothermal method under varied temperature conditions (190-220 °C). Although the physical properties of VSe have been studied before, only limited morphological change or application were explored. This study, for the first time, applied VSe as the electrocatalytic counter electrode (CE) in dye-sensitized solar cells (DSSCs) and showed an attractive cell efficiency.

Transition-Metal-Doped Molybdenum Diselenides with Defects and Abundant Active Sites for Efficient Performances of Enzymatic Biofuel Cell and Supercapacitor Applications.

We have demonstrated the synthesis of defect-rich Ni-doped MoSe nanoplates (NiMoSe) and their application as an efficient electrocatalyst for enzymatic biofuel cells and electrochemical pseudocapacitors. In this study, a new type of interpretation is proposed that a defective surface facilitates the effective entrapment of enzymes (glucose oxidase (GOD), laccase) for biofuel cells and additional ion diffusion for Faradic charge-discharge reaction. The transmission electron microscopy and UV-vis spectroscopy techniques scrutinized the formation of defects/distortions and the resultant successful entrapment of enzymes.