Work Function Research Articles

Ohmic Contact Resistance in SiC Diodes with Ti and NiSi P<sup>+</sup> Contacts

Ohmic contacts play a major role in the signal transfer between the semiconductor device and the external circuitry. One of the main technological issues to develop high-performance SiC-based devices is the control of metal/SiC contact properties to fabricate low resistance and high stability SiC Ohmic contacts to p-type SiC. This is mostly due to intrinsic SiC characteristics like large work function, low dopant activation for p-type materials and low hole mobility. These limits are even more emphasized in SiC JBS or MPS diodes, where Schottky and Ohmic contacts on the P doped regions embedded in the active area to improve surge ruggedness are usually formed by using the same metallization process. This naturally results either in a high Schottky barrier height in the Schottky contact with consequent increase of the conduction loss at low currents or in a poorly conductive Ohmic contact, leading to reduced IFSM capability. Therefore, the optimization and control of the process parameters like for example the P+ doping concentration peak underneath the metallization layer and the annealing process temperatures is crucial to obtain a good Ohmic contact and enhance the device´s robustness against surge current.

MXene-Embedded PEDOT:PSS Hole-Transport Material for Lead-Free Perovskite Solar Cells.

Improving the energy alignment between charge-transport layers and the perovskite is crucial for further enhancing the photovoltaic performance of tin-based perovskite solar cells (PSCs). Herein, the role of Ti3C2T x MXene in a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transport layer (HTL) on the photovoltaic properties of PSCs is investigated as a function of its concentration. An improved perovskite film formation with reduced pinhole density and a more uniform contact potential difference is noted when MXene is embedded in the PEDOT:PSS HTL. The work function of the HTL is increased according to photoelectronic measurements, leading to a favorable energy alignment with the HOMO of PEA0.2FA0.8SnI3 perovskite. PSCs fabricated using a MXene-embedded PEDOT:PSS HTL delivered a power conversion efficiency (PCE) of 8.35% compared to 7.35% from the pristine counterpart, while retaining ∼90% of its initial PCE after 450 h of storage in a N2 atmosphere.

Reduction of a two-dimensional crystalline MoO3 monolayer

The atomic structure of MoOx films formed upon a gradual thermal reduction of an ordered MoO3 monolayer on the Pd(100) substrate was explored via surface science characterization techniques and density functional theory (DFT) calculations. Two main reduction stages were identified. First, the initial oxygen excess was gradually eliminated by altering the domain boundary length, orientation, and atomic structure. The films nevertheless remained O-rich, with numerous terminal oxygen atoms (formation of MoO groups), and an elevated work function. Second, multiple ordered O-lean phases were formed, characterized by either very few or no terminal oxygen atoms, and a much smaller surface work function. According to calculations, the positive charging of the Pd substrate stabilizes the oxygen excess during the first stage, but during the second reduction stage, the substrate becomes negatively charged, stabilizing enhanced cation oxidation states. On their basis, the mechanisms underlying the oxygen release from the initial c(2 × 2) domains were disclosed. The experiments showed that the film reduction is perfectly reversible, which highlights the very promising properties of the MoO3/Pd system for heterogeneous catalysis.

Construction of 0D Ti3C2Tx MXene nanoparticles sensitized 1D TiO2 nanotube arrays for enhanced photocatalytic and photoelectrochemical properties

Developing efficient photocatalysts with highly active facets and appropriate cocatalyst hybridization to form heterostructure is a valid way to expedite the separation of photoexcited electron-hole pairs. Herein, a novel 0D/1D Ti3C2Tx MXene/TiO2 photocatalyst was fabricated for photoelectrochemical (PEC) water splitting and tetracycline antibiotic photocatalytic degradation. Meanwhile, highly-exposed TiO2 nanotube arrays were prepared by electrochemical anodizing method, and Ti3C2Tx nanoparticles with mixed terminal group were uniformly grown on the surface of TiO2 through the hydrothermal and solvothermal process, respectively. Compared with pure TiO2, the Ti3C2Tx/TiO2 heterostructure exhibited different degrees of enhancement in PEC and photocatalytic degradation activities under simulated sunlight. The TNT/M-h sample yielded a photocurrent density of 1.77 mA cm−2 at 0 V (vs. SCE) and achieved a 95.57 % photocatalytic removal rate of tetracycline within 140 min. The excellent performance originated from the strong interfacial contact and work function discrepancy between the ordered tubular structure of TiO2 and 0D Ti3C2Tx nanoparticles, which realized the high-efficiency photogeneration and transfer of electron-hole pairs.

Investigating Cu-Site Doped Cu-Sb-S Nanoparticles Using Photoelectron and Electron Paramagnetic Resonance Spectroscopy.

Tetrahedrite (Cu12Sb4S13) and famatinite (Cu3SbS4) are good candidates for green energy applications because they possess promising thermoelectric and photovoltaic properties as well as contain earth-abundant and nontoxic constituents. Herein, X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and electron paramagnetic resonance spectroscopy (EPR) methods examined inherent electronic properties and interatomic magnetic interactions of Cu-site doped tetrahedrite and famatinite nanomaterials. An energy-efficient modified polyol method was utilized for the synthesis of tetrahedrite and famatinite nanoparticles doped on the Cu-site with Zn, Fe, Ni, Mn, and Co. This is the first parallel study of tetrahedrite and famatinite nanomaterials with XPS, UPS, and EPR methods alongside a systematic analysis of dopant-dependent effects on the electronic structure and magnetic interactions for each material. XPS showed that the Cu and Sb species in tetrahedrite and famatinite possess different oxidation states, while UPS characterization reveals larger dopant-dependent shifts in the work function for tetrahedrite nanoparticles (4.21 to 4.79 eV) than for famatinite nanoparticles (4.57 to 4.77 eV). Finally, all famatinite nanoparticles display an EPR signal, indicating trace amounts of paramagnetic Cu(II) present below the detection limit of XPS. For tetrahedrite, EPR signatures were observed only for the Zn-doped and Mn-doped nanoparticles, suggesting signal broadening from Cu-Cu spin exchange or spin-lattice relaxation. This study demonstrates the complementary nature of XPS and EPR techniques for studying the oxidation states of metals in solid-state nanomaterials. Comparing the electronic and magnetic properties of tetrahedrite and famatinite while studying the impact of dopant incorporation will guide future endeavors in designing sustainable, high-performance materials for renewable energy applications.

High-Yield Exfoliation of Stanene Nanodots for High-Performance Organic Light-Emitting Diodes.

Stanene nanodots (SnNDs) derived from layered tin have attracted considerable interest due to their conveniently tunable bandgap and topological superconductivity. However, high-yield exfoliation of ultrathin SnNDs is still a challenge due to the short layer spacing and strong binding energy. In this work, atomically thin SnNDs with a uniform size of 2.3 nm are successfully prepared by utilizing imidazolium ionic liquid-assisted exfoliation. The obtained SnNDs possess a wide bandgap of 2.69 eV, along with notable solvent compatibility (well dispersed in both polar and nonpolar solvents) and excellent stability. Furthermore, we construct Ir(ppy)3-based green OLED with hybridizing SnNDs and graphene oxide (GO) as the hole injection layer (HIL). It proves that the application of SnNDs helps to modulate the work function and passivate surface defects of GO, increasing hole mobility and thereby improving the device performance. Compared to the PEDOT:PSS-based control device, the optimized SnNDs-GO-based OLED demonstrates an improvement of 6.56, 41.06, and 8.16% in current efficiency (CE), power efficiency (PE), and external quantum efficiency (EQE), respectively. This work not only introduces a new approach to preparing 2D SnNDs but also creates a novel HIL material for OLED devices.

Introducing Bi2S3 Interlayer to Synergistically Modify Mo Back Contact and Regulate Bulk Defects in Kesterite Solar Cells.

A suitable interlayer between the Mo back electrode and kesterite absorber layer has been proven to have a positive effect on limiting the bulk defects of the absorber by the constitute diffusion. Here, a thin Bi2S3 layer is used as the back-interface intermediate layer for the first time, this innovative approach allows for simultaneous modification of the back contact and reduction of bulk defects, resulting in improving the power conversion efficiency of the kesterite device from 9.66% to 11.8%. The evaporated Bi2O3 thin films turn into the Bi2S3 interlayers after sintering the Cu2ZnSnS4 precursor thin films. The Bi2S3 interlayer can inhibit the decomposition reaction of back contact and suppress the formation of the secondary phases. It can also optimize the Fermi level offset and promote the separation of the photoinduced carriers, resulting from its characteristic of high work function. Besides, a small part of the Bi element can diffuse into Cu2ZnSn(S, Se)4 film and induce the crystal growth and restrain Zn-related defects, which is attributed to forming the low melting-point liquid BiSex phase during the high-temperature selenization process. The conclusions highlight the bifunction of the thin Bi2S3 intermediate layer, which can provide a new approach to improve the photoelectric conversion efficiency of kesterite solar cells.

Hazardous CO, NO, NH3 gases over boron and beryllium doped α-CN monolayers: A first principles study for sensing and removal applications

The exploration of two-dimensional (2D) honeycomb layered structure (HLS) has garnered significant attention due to their multifunctional properties, with diverse applications emerging in various fields. Motivated by the challenges posed by hazardous gases such as CO, NO, NH3 and inspired by the unique properties of 2D HLS this first principles study digs into the structural, electronic, and sensing properties of Boron and Beryllium doped α-CN monolayers. Rendering the structural and electronic variations induced by B and Be doping, our analysis reveals distinct functionalities for α-CN monolayers. Boron doping at the C-site exhibits promise for NO and NH3 sensing (with 73 % and 77 % increment in adsorption energies), while B-doping at the N-site enhances suitability for gas removal applications. Similarly, Be doping demonstrates effectiveness in gas removal across both C and N sites. Notably, the ultra-fast response (2.31 × 10−8 s) observed for NO adsorption over B-doped α-CN highlights its potential as a rapid sensor. Additionally, work function analysis suggests the suitability of B-doped α-CN for φ-type sensing in NH3 adsorption. These findings underscore the applicability of doped α-CN monolayers in gas sensing mechanisms.

Solving the Contradiction of Work Function and Conductivity in PEDOT:PSS to Achieve High‐Performance Perovskite Light‐Emitting Diode via Aniline Interface Modification

AbstractPoly (3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is one of the most widely used functional materials for hole transport layer in perovskite light‐emitting diode (LED). Tuning its work function (WF) and conductivity (κ) is a key issue for promoting perovskite LED performance. While decreasing its WF always reduces its κ and vice versa. Solving such contradiction is quite significant for promoting the development and commercialization of perovskite LED. Herein, the aniline (Ani) is employed for PEDOT:PSS interface modification. Ani inserted between PEDOT and PSS to weaken electrostatic interaction between sulfonic acid group in PSS chain and thiophene group in PEDOT chain, which results in increased delocalized electrons to enhance its κ. More importantly, the acid–base reaction decreases high acidity of PEDOT:PSS, which is an effective way to increase its WF and decrease its interface defects density. Meanwhile, such interface modification avoids PEDOT:PSS phase separation and ensures the uniformity of film. After Ani modification, the WF of PEDOT:PSS increase from 5.16 to 5.31 eV, the κ increases from 0.30 to 8.62 S cm−1, and the hole mobility enhances from 0.716 × 10−6 to 1.306 × 10−6 cm2 V−1 s−1. Modified PEDOT:PSS boost CsPbI3 LED achieving a maximum external quantum efficiency of 17.70%.

Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically‐Stable Low‐Temperature Lithium‐Ion Batteries

AbstractGraphite (Gr)‐based lithium‐ion batteries with admirable electrochemical performance below −20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+‐solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically‐stable solid electrolyte interphase (SEI) without compromising strong Li+‐solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature‐dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low‐temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e−) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4‐based, inorganics‐enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e− blocking and rapid desolvation, and as a result, much suppressed Li‐metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low‐temperature battery performances. Overall, our work originally provides visualized guides to improve low‐temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.

Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically-Stable Low-Temperature Lithium-Ion Batteries.

Graphite (Gr)-based lithium-ion batteries with admirable electrochemical performance below -20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+-solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically-stable solid electrolyte interphase (SEI) without compromising strong Li+-solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature-dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low-temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e-) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4-based, inorganics-enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e- blocking and rapid desolvation, and as a result, much suppressed Li-metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low-temperature battery performances. Overall, our work originally provides visualized guides to improve low-temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.

Interfacial thermal conductance in 2D WS2/MoSe2 and MoS2/MoSe2 lateral heterostructures

In-plane Transition Metal Dichalcogenides (TMDs) heterostructures hold immense potential for various applications in the modern semiconductor industry, including electronics, optoelectronics, and photovoltaic devices. Different TMD monolayers can be ‘stitched’ together to construct an in-plane (lateral) heterostructure. As different TMD monolayers present different work functions and have their intrinsic shortcomings, a TMD heterostructure is an excellent form to optimize their properties and to achieve the best functionality. This requires a quantitative understanding of the properties of the interfaces in the heterostructures. In this work, we perform nonequilibrium molecular dynamics simulations, based on a parametrized Stillinger-Weber potential, to investigates the thermal conductance of the interfaces in 2D WS2/MoSe2 and MoS2/MoSe2 in-plane heterostructures, as well as in 2D lateral WS2/MoSe2 superlattices. Three distinct types of interfaces, including defect-free coherent interfaces, interfaces with the 5∣7 defects, and the alloy-like incoherent interfaces, are explored. The effects of interphase structure and temperature are quantified. Phonon density of states (PDOS) analysis is used to understand the effect of different interphase structures. The effect of superlattice period on thermal conductance of the superlattices has also been quantified.

Photocatalytic CO2‐to‐CH4 Conversion with Ultrahigh Selectivity of 95.93% on S‐Vacancy Modulated Spatial In2S3/In2O3 Heterojunction

AbstractPhotocatalytic conversion of CO2 to methane faces challenges due to the stability of CO2, unpredictable intermediates, and complex electron transfer steps. Herein, a spatial In2S3/In2O3 heterojunction with abundant S vacancies (ISIO(VS)) is obtained through facile Polyvinylpyrrolidone (PVP) treatment to reach a methane yield of 16.52 µmol·g−1·h−1 with a selectivity of 95.93%, which is the highest among reported In2S3 and In2O3 based catalysts. The work function (Wf), differential charge density, and Kelvin Probe Force Microscopy (KPFM) results confirm that S vacancies strengthen the built‐in electric field (BEF) of In2S3/In2O3 (ISIO) heterojunctions, improving carrier separation. Density functional theory (DFT) calculations reveal that S vacancies induce electron redistribution, facilitating adsorption and activation of CO2 and *CO intermediate, thus promoting hydrogenation to yield *CHO. The reaction pathway of photocatalytic CO2 reduction is revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and Gibbs free energy (ΔG). The S vacancies modify electronic orbitals and the highest occupied molecular orbital (HOMO) of In atom, resulting in a stronger interaction between the catalyst and *CHO, which reduces ΔG*CHO and regulates the selectivity of CH4. This study paves a new avenue for the design of photocatalysts with highly selective reduction of CO2 to CH4 through defect engineering.

Thiophene Oligomers with Low Cost and Easy Synthesis for Efficient Organic Solar Cells

Hole‐transporting layer (HTL) materials with sufficient hole collection ability, noncorrosive nature, and easy preparation are strongly desired for the field of organic solar cells (OSCs). The development of new materials and synthetic methods has been proved to be the essential approach to improve the HTL performances. Herein, a series of thiophene oligomers TO‐P1, TO‐P2, and TO‐P3 are designed and synthesized through coupling reaction by using the polyoxometalates as the oxidizing reagents. The thiophene oligomers can be readily synthesized under ambient condition with high yield. Among the as‐prepared thiophene oligomers, TO‐P2 exhibits neutral pH, sufficient work function, and high conductivity, endowing the HTL with excellent hole collection ability. Also, TO‐P2 possesses good chemical stability and satisfied solution processability, which is important for practical use. By using TO‐P2 as HTL, OSC shows a photovoltaic efficiency of 17.25%. Furthermore, TO‐P2 is a universal HTL that can be used to fabricate efficient OSCs with various active layers. More importantly, TO‐P2 shows good compatibility with large‐area processing technique. A 1 cm2 OSC is fabricated by using a blade‐coated TO‐P2 HTL, exhibiting a power conversion efficiency of 15.0%. The easy preparation and noncorrosive nature endow TO‐P2 with great potential application in OSCs.

Co-doped bismuth vanadate/zinc tungstate heterojunction with dual internal electric fields for efficient photocatalytic reduction of carbon dioxide

Enhanced carriers separation on photocatalysts is crucial for improving photocatalytic activity. In this paper, the Co-doped BiVO4/ZnWO4 S-scheme heterojunctions were constructed to induce double internal electric fields (IEFs) for enhancing charges separation and transfer for efficient photocatalytic reduction of CO2. The photocatalytic CO2 reduction efficiencies of the heterojunctions were significantly enhanced as compared with the counterparts. The optimized Co-doped BiVO4/ZnWO4 exhibited the highest CO yield of 138.4 μmol·g−1·h−1, which were 86.5 and 1.4 folds of the BiVO4 and Co-doped BiVO4. Results of X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), and work function demonstrated that charge transfer path of Co-doped BiVO4/ZnWO4 conformed to S-scheme heterojunction mechanism. The kelvin probe force microscopy (KPFM) and density functional theory (DFT) calculations of the differential charge distributions confirmed the existence of double IEFs, which accelerated carrier separation and improved CO2 adsorption and activation. In addition, in-situ Fourier transform infrared spectroscopy (ISFT-IR) revealed that HCOO− was the major intermediate during the CO2 reaction. This study provides a feasible means to develop composite photocatalysts with dual IEFs for effective photocatalytic CO2 reduction.

Characterization of o-B2N2 monolayer surface for effective sensing and detection of toxic nitrogen oxides

Using density functional theory (DFT), researchers examined how the o-B2N2 monolayer interacts with toxic gases such as NO2 and NO. They investigated various aspects of the adsorption system, including its state density, differential charge density, optimal structure, and other features. The analysis revealed that the o-B2N2 monolayer remained stable throughout the adsorption process. The researchers also examined additional properties of the adsorption process, including work function, sensitivity, response time, recovery time, and energy gap to gain a deeper comprehension of adsorption features of NO2 and NO gases. The findings indicate that the o-B2N2 monolayer exhibits a shorter recovery time at higher temperatures, suggesting improved performance. Furthermore, the monolayer demonstrates higher sensitivity and a greater variation in the work function, indicating its superior adsorption capabilities. The findings suggest that the o-B2N2 monolayer has potential with great promise as an adsorbent for toxic gases like NO2 and NO. This has practical implications for applications such as air purification and environmental protection. Our findings demonstrate that the o-B2N2 monolayer serves as an effective gas sensor at room temperature, exhibiting both high sensitivity and selectivity in detecting NO2 and NO gases. Moreover, it can be reused multiple times for gas detection purposes.

Adsorption behaviour of transition metal atoms on pristine and defective two-dimensional MgAl2S4 monolayer

The electronic structures and magnetic properties of two-dimensional MgAl2S4 monolayer, as well as the adsorption configurations, adsorption energy, and charge transfer phenomena of transition metal atoms adsorbed on both pristine and defective monolayer MgAl2S4 surfaces were systematically investigated. The results show that MgAl2S4 at equilibrium is a nonmagnetic indirect semiconductor with a bandgap of 1.908 eV. The adsorption energies of the adsorbed structures on both pristine and defective MgAl2S4 surfaces are negative, indicating good stability for all configurations. The adsorption of transition metal atoms leads to the transformation of the MgAl2S4 monolayer from non-magnetic semiconductor to magnetic semiconductor, bipolar magnetic semiconductor, half-metal, and metal. In addition, there is a good modulation of the bandgap. The significant charge transfer between MgAl2S4 monolayer and the transition metal atoms implies the formation of chemical bonds. The lower work function implies that the MgAl2S4 and transition metal atom adsorption structures benefit electron emission. Thus, research has revealed that the adsorption configurations of transition metal atoms on the surface of MgAl2S4 monolayer offers new possibilities for the fabrication of spintronic devices, the design of highly efficient catalysts, and the application of emission devices.

Green and solid state reduction of GO monolayers sandwiched between Arachidic acid LB layers

A novel, single step and environment friendly solid state approach for reduction of graphene oxide (GO) monolayers has been demonstrated, in which, arachidic acid/GO/arachidic acid (AA/GO/AA) sandwich structure obtained by Langmuir-Blodgett (LB) technique was heat treated at moderate temperatures to obtain RGO sheets. Heat treatment of AA/GO/AA sandwich structure at 200 °C results in substantial reduction of GO, with concurrent removal of AA molecules. Such developed RGO sheets possess sp2-C content of ∼69 %, O/C ratio of ∼0.17 and significantly reduced I(D)/I(G) ratio of ∼1.1. Ultraviolet photoelectron spectroscopy (UPS) studies on RGO sheets evidenced significant increase in density of states in immediate vicinity of Fermi level and decrease in work function after reduction. Bottom gated field effect transistors fabricated with isolated RGO sheets displayed charge neutrality point at a positive gate voltage, indicating p-type nature, consistent with UPS and electrostatic force microscopy (EFM) measurement results. The RGO sheets obtained by heat treatment of AA/GO/AA sandwich structure exhibited conductivity in the range of 2–7 S/cm and field effect mobility of 0.03–2 cm2/Vs, which are comparable with values reported for RGO sheets obtained by various chemical/thermal reduction procedures. The extent of GO reduction is determined primarily by proximity of AA molecules and found to be unaltered with either escalation of heat treatment temperature or increase of AA content in sandwich structure. The single-step GO reduction approach demonstrated in this work is an effective way for development of RGO monolayers with high structural quality towards graphene-based electronic device applications.

Engineering MOF@LDH heterojunction with strong interfacial built-in electric field towards enhanced electrocatalytic water oxidation

Guiding the dynamic reconstruction of the oxygen evolution reaction (OER) is crucial for realizing the industrial application of hydrogen production through water electrolysis. In this study, we have intricately designed a built-in electric field (BIEF) between MIL-88B(Fe) and layered double hydroxide (LDH) with an adjusted work function difference. This design drives an asymmetric interfacial electron distribution, enhancing electron accumulation at the Fe sites within MIL-88B(Fe) and electron-deficient LDHs. Consequently, this setup promotes the surface dynamic reconstruction of LDHs into highly active oxyhydroxides, while simultaneously slowing down the rapid dissolution of Fe during OER operation. This optimization improves the adsorption/desorption of oxygen intermediates, ensuring a sustained high OER activity during long-term electrochemical operation. As expected, the optimal MIL-88B(Fe)@NiCo LDH configuration demonstrates a remarkably low overpotential of only 279 mV at 10 mA cm−2, maintaining operational stability for 70 h. This research significantly advances our understanding of the dynamic reconstruction of MOF@LDH heterojunctions and introduces a straightforward strategy for engineering BIEF to guide this process effectively.

Janus piezoelectric ZrSi[formula omitted]H ([formula omitted] N, P, As) semiconductors with Raman response and high carrier mobility by a first-principles investigation

Motivated by the growing demand for new materials with novel properties, in the present work we design a series of two-dimensional Janus ZrSiZ3H (Z= N, P, As) monolayers and examine their physical features by using first-principle investigations. All three ZrSiN3H, ZrSiP3H, and ZrSiAs3H monolayers have good thermodynamic and mechanical stabilities from the ab initio molecular dynamics and obtained elastic coefficients results. The ZrSiZ3H systems also exhibit Raman response and piezoelectricity. Among three monolayers, the ZrSiAs3H possesses the highest in-plane and extra out-of-plane piezoelectric effects with d11 and d31 values of −7.88 pm/V and −0.19 pm/V, respectively. In addition, from calculated band structures, the ZrSiZ3H systems are found as semiconductors with bandgap energies varying from 0.90 to 3.00 eV at the Heyd–Scuseria–Ernzerhof theoretical level. The Zr-d and P-p orbitals give significant contributions to the band edge formation of all proposed configurations. The electrons can escape more easily from the H side than from the Z side due to their lower work functions. Notably, the ZrSiZ3H structures show anisotropic carrier mobilities along two in-plane axes. The ZrSiP3H and ZrSiAs3H monolayers exhibit high electron mobility in the x direction of 6925.53 and 6291.17 cm2V−1s−1, respectively. Our findings highlight the ZrSiZ3H systems as stable piezoelectric and electronic semiconductors for technological applications.