Strain-engineered bright excitons and a nearly flat band in monolayer SnNBr for high-speed LED applications.

With the ever-increasing volume of data, the need for systems that can handle massive datasets is becoming gradually critical. High performance visible light communication (VLC) systems offer an expedient solution, yet its widespread adoption is hindered by the limited modulation bandwidth of light emitting diodes (LEDs). Through many-body perturbation theory within the approximation and the Bethe-Salpeter equation (BSE) approach, this work introduces a novel approach to achieving exceptionally high modulation bandwidth by utilizing the nearly flat bands in two-dimensional semiconductors, using SnNBr monolayer as a prototype material for overcoming this bottleneck.

Harnessing orbital and valley thermal transport in 2D materials: The significance of inversion symmetry.

Orbitronics and valleytronics, analogous to spintronics, leverage the orbital degree of freedom and the valley degree of freedom of electrons to carry information, promising significant advancements in information processing. In this study, we disentangle the orbital and valley Nernst effect in 2D monolayers, based on the global symmetry of the monolayers. We conduct an in-depth analysis of the orbital (valley) Nernst effect in inversion symmetric (asymmetric) monolayers, using an analytical tight binding model.

Ferroelectricity-controlled magnetic ordering and spin photocurrent in NiCl/GeS multiferroic heterostructures.

Controlling magnetism solely through electrical means is indeed a significant challenge, yet holds great potential for advancing information technology. Herein, our investigation presents a promising avenue for electrically manipulating magnetic ordering within 2D van der Waals NiCl/GeS heterostructures. These heterostructures, characterized by their unique magnetic-ferroelectric (FE) layer stacking, demonstrate spin-constrained photoelectric memory, enabling low-power electrical writing and non-destructive optical reading.

Conflux of spin Nernst and spin Hall effect in ZnCuSnSeTopological Insulator.

A comprehensive exploration of the intriguing phenomena known as the spin Nernst effect (SNE) and the spin Hall effect (SHE) within the context of nonmagnetic strong topological insulatorZnCu2SnSe4, has been carried out employing first-principles calculations. Our theoretical calculations unveil significantly large intrinsic spin Nernst conductivity (SNC) and spin Hall conductivity (SHC) in the bulk topological insulatorZnCu2SnSe4. Delving deeper into the intricacies of our findings, we elucidate how the inverted band order in the topological materials drastically influences the spin Berry curvature, consequently exerting a profound impact on SHC and SNC.

Temperature-driven journey of dark excitons to efficient photocatalytic water splitting in β-AsP.

Limited availability of photogenerated charge carriers in two-dimensional (2D) materials, due to high exciton binding energies, is a major bottleneck in achieving efficient photocatalytic water splitting (PWS). Strong excitonic effects in 2D materials demand precise attention to electron-electron correlation, electron-hole interaction and electron-phonon coupling simultaneously. In this work, we explore the temperature-dependent electronic and optical responses of an efficient photocatalyst, blue-AsP (β-AsP), by integrating electron-phonon coupling into state-of-the-art GW + BSE calculations.

Regulating excitonic effects in non-oxide based XPSe (X = Cd, Zn) monolayers towards enhanced photocatalysis for overall water splitting.

The non-oxide 2D materials have garnered considerable interest due to their potential utilization as photocatalysts, which offer a superior substitute to metal-oxide-based photocatalysts. This study investigates the impact of the dielectric environment on the size and binding energy of excitons in atomically thin, experimentally synthesized semiconducting monolayers [XPSe, X = (Cd, Zn)] to address the critical problem of electron-hole recombination, which significantly hinders the efficiency of most photocatalysts. We employ a precise non-hydrogenic model surpassing the hydrogenic-based Mott-Wannier model.

Anisotropy in colossal piezoelectricity, giant Rashba effect and ultrahigh carrier mobility in Janus structures of quintuple BiX(X = S, Se) monolayers.

Due to the asymmetric structures, two-dimensional Janus materials have gained significant attention in research for their intriguing piezoelectric and spintronic properties. In the present work, quintuple BiX(X = S, Se) monolayers (MLs) have been modified to create stable Janus BiXY (X ≠ Y = S, Se) MLs that display piezoelectricity in both the planes along with Rashba effect. The out-of-plane piezoelectric constant () is 41.

Insights into selected 2D piezo Rashba semiconductors for self-powered flexible piezo spintronics: material to contact properties.

The new paradigm in electronics consists in realizing the seamless integration of many properties latent in nanomaterials, such as mechanical flexibility, strong spin-orbit coupling (Rashba spin splitting-RSS), and piezoelectricity. Taking cues from the pointers given on 1D ZnO nanowires (20181811-20), the concept can be extended to multifunctional two-dimensional (2D) materials, which can serve as an ideal platform in next-generation electronics such as self-powered flexible piezo-spintronic device. However, a microscopically clear understanding reachable from the state-of-the-art density functional theory-based approaches is a prerequisite to advancing this research domain.

Engineering Catalytically Active Sites by Sculpting Artificial Edges on MoS Basal Plane for Dinitrogen Reduction at a Low Overpotential.

Engineering catalytically active sites have been a challenge so far and often relies on optimization of synthesis routes, which can at most provide quantitative enhancement of active facets, however, cannot provide control over choosing orientation, geometry and spatial distribution of the active sites. Artificially sculpting catalytically active sites via laser-etching technique can provide a new prospect in this field and offer a new species of nanocatalyst for achieving superior selectivity and attaining maximum yield via absolute control over defining their location and geometry of every active site at a nanoscale precision. In this work, a controlled protocol of artificial surface engineering is shown by focused laser irradiation on pristine MoS flakes, which are confirmed as catalytic sites by electrodeposition of AuNPs.

Experimental and computational insights into luminescence in atomically precise bimetallic AuCu(MPA) ( = 0-2) clusters.

Bimetallic nanoclusters (NCs) have emerged as a new class of luminescent materials for potential applications in sensing, bio-imaging, and light-emitting diodes (LEDs). Here, we have synthesized gold-copper bimetallic nanoclusters (AuCu NCs) using a one-step co-reduction method and tuned the emission wavelength from 520 nm to 620 nm by changing the [Cu]/[Au] molar ratio. The quantum yield (QY) increases from 6% to 13% upon incorporation of the Cu atom in the Au NCs.

Nanocatalytic Interface to Decode the Phytovolatile Language for Latent Crop Diagnosis in Future Farms.

Crop diseases cause the release of volatiles. Here, the use of an SnO-based chemoresistive sensor for early diagnosis has been attempted. Ionone is one of the signature volatiles released by the enzymatic and nonenzymatic cleavage of carotene at the latent stage of some biotic stresses.

Spin-Current Modulation in Hexagonal Buckled ZnTe and CdTe Monolayers for Self-Powered Flexible-Piezo-Spintronic Devices.

The next-generation spintronic device demands the gated control of spin transport across the semiconducting channel through the replacement of the external gate voltage source by the piezo potential, as experimentally demonstrated in Zhu et al. , , 12 (2), 1811-1820. Consequently, a high level of out-of-plane piezoelectricity together with a large Rashba spin splitting is sought after in semiconducting channel materials.

Conflux of tunable Rashba effect and piezoelectricity in flexible magnesium monochalcogenide monolayers for next-generation spintronic devices.

The coupling of piezoelectric properties with Rashba spin-orbit coupling (SOC) has proven to be the limit breaker that paves the way for a self-powered spintronic device (ACS Nano, 2018, 12, 1811-1820). For further advancement in next-generation devices, a new class of buckled, hexagonal magnesium-based chalcogenide monolayers (MgX; X = S, Se, Te) have been predicted which are direct band gap semiconductors satisfying all the stability criteria. The MgTe monolayer shows a strong SOC with a Rashba constant of 0.

Group-IV(A) Janus dichalcogenide monolayers and their interfaces straddle gigantic shear and in-plane piezoelectricity.

Inversion symmetry in the 1T-phase of pristine dichalcogenide monolayer MX2 (M = Ge, Sn; X = S, Se) is broken in their Janus structures, MXY (M = Ge, Sn; X ≠ Y = S, Se), which induces an in-plane piezoelectric coefficient, d22 = 4.09 (2.15) pm V-1 and a shear piezoelectric coefficient, d15 = 7.

Interfacial hybridization of Janus MoSSe and BX (X = P, As) monolayers for ultrathin excitonic solar cells, nanopiezotronics and low-power memory devices.

In this work, we explored the interfacial two-dimensional (2D) physics and significant advancements in the application prospects of MoSSe monolayer when it is combined with a boron pnictide (BP, BAs) monolayer in a van der Waals heterostructure (vdWH) setup. The constructed vdWHs were found to be mechanically and dynamically stable, and they form type-II p-n heterojunctions. Thus, the photogenerated electron-hole pairs are spatially separated.

Two-dimensional ultrathin van der Waals heterostructures of indium selenide and boron monophosphide for superfast nanoelectronics, excitonic solar cells, and digital data storage devices.

Semiconducting indium selenide (InSe) monolayers have drawn a great deal of attention among all the chalcogenide two-dimensional materials on account of their high electron mobility; however, they suffer from low hole mobility. This inherent limitation of an InSe monolayer can be overcome by stacking it on top of a boron phosphide (BP) monolayer, where the complementary properties of BP can bring additional benefits. The electronic, optical, and external perturbation-dependent electronic properties of InSe/BP hetero-bilayers have been systematically investigated within density functional theory in anticipation of its cutting-edge applications.

Exceptional mechano-electronic properties in the HfN monolayer: a promising candidate in low-power flexible electronics, memory devices and photocatalysis.

The response of the electronic properties of the HfN2 monolayer to external perturbation, such as strain and electric fields, has been extensively investigated using density functional theory calculations for its device-based applications and photocatalysis. The HfN2 monolayer is found to be a semiconductor showing a direct band gap of 1.44 eV, which is widely tunable by 0.

Experimental and Theoretical Study into Interface Structure and Band Alignment of the CuZn Cd SnS Heterointerface for Photovoltaic Applications.

To improve the constraints of kesterite CuZnSnS (CZTS) solar cell, such as undesirable band alignment at p-n interfaces, bandgap tuning, and fast carrier recombination, cadmium (Cd) is introduced into CZTS nanocrystals forming CuZn Cd SnS through cost-effective solution-based method without postannealing or sulfurization treatments. A synergetic experimental-theoretical approach was employed to characterize and assess the optoelectronic properties of CuZn Cd SnS materials. Tunable direct band gap energy ranging from 1.

Ultra-low lattice thermal conductivity and giant phonon-electric field coupling in hafnium dichalcogenide monolayers.

Phonons in crystalline solids are of utmost importance in governing its lattice thermal conductivity (k ). In this work, k in hafnium (Hf) dichalcogenide monolayers has been investigated based on ab initio DFT coupled to linearized Boltzmann transport equation together with single-mode relaxation-time approximation. Ultra-low k found in HfS (2.

Superhigh flexibility and out-of-plane piezoelectricity together with strong anharmonic phonon scattering induced extremely low lattice thermal conductivity in hexagonal buckled CdX (XS, Se) monolayers.

Although CdX (X = S, Se) has been mostly studied in the field of photocatalysis, photovoltaics, their intrinsic properties, such as, mechanical, piezoelectric, electron and phonon transport properties have been completely overlooked in buckled CdX monolayers. Ultra-low lattice thermal conductivity [1.08 W mK(0.

Tweaking the Physics of Interfaces between Monolayers of Buckled Cadmium Sulfide for a Superhigh Piezoelectricity, Excitonic Solar Cell Efficiency, and Thermoelectricity.

Interfaces of heterostructures are routinely studied for different applications. Interestingly, monolayers of the same material when interfaced in an unconventional manner can bring about novel properties. For instance, CdS monolayers, stacked in a particular order, are found to show unprecedented potential in the conversion of nanomechanical energy, solar energy, and waste heat into electricity, which has been systematically investigated in this work, using DFT-based approaches.

Proton-Triggered Fluorescence Switching in Self-Exfoliated Ionic Covalent Organic Nanosheets for Applications in Selective Detection of Anions.

The exfoliation of covalent organic frameworks into covalent organic nanosheets (CONs) not only helps to reduce fluorescence turn-off phenomena but also provides well-exposed active sites for fast response and recovery for various applications. The present work is an example of rational designing of a structure constructed by condensing triaminoguanidinium chloride (TG), an intrinsic ionic linker, with a fluorophore, 2, 5-dimethoxyterephthalaldehyde (DA), to produce highly fluorescent self-exfoliable ionic CONs (DATG-iCONs). These fluorescent iCONs are able to sense fluoride ions selectively down to the ppb level via the fluorescence turn-off mechanism.

Interfacing Boron Monophosphide with Molybdenum Disulfide for an Ultrahigh Performance in Thermoelectrics, Two-Dimensional Excitonic Solar Cells, and Nanopiezotronics.

A stable ultrathin 2D van der Waals (vdW) heterobilayer, based on the recently synthesized boron monophosphide (BP) and the widely studied molybdenum disulfide (MoS), has been systematically explored for the conversion of waste heat, solar energy, and nanomechanical energy into electricity. It shows a gigantic figure of merit (ZT) > 12 (4) for p (n)-type doping at 800 K, which is the highest ever reported till date. At room temperature (300 K), ZT reaches 1.

Superhigh out-of-plane piezoelectricity, low thermal conductivity and photocatalytic abilities in ultrathin 2D van der Waals heterostructures of boron monophosphide and gallium nitride.

A stable 2D van der Waals (vdW) heterobilayer, constituted by boron monophosphide (BP) and Gallium Nitride (GaN) monolayers, has been explored for different kinds of energy conversion and nanoelectronics. The nearly matched lattice constants of GaN and BP are commensurate with each other in their lattice structures. The out-of-plane inversion asymmetry coupled with the large difference in atomic charges between the GaN and BP monolayers induces in the heterobilayer a giant out-of-plane piezoelectric coefficient (|d33|max ≈ 40 pm V-1), which is the highest ever reported in 2D materials of a finite thickness.

Compressive strain induced enhancement in thermoelectric-power-factor in monolayer MoS nanosheet.

Strain and temperature induced tunability in the thermoelectric properties in monolayer MoS (ML-MoS) has been demonstrated using density functional theory coupled to semi-classical Boltzmann transport theory. Compressive strain, in general and uniaxial compressive strain (along the zig-zag direction), in particular, is found to be most effective in enhancing the thermoelectric power factor, owing to the higher electronic mobility and its sensitivity to lattice compression along this direction. Variation in the Seebeck coefficient and electronic band gap with strain is found to follow the Goldsmid-Sharp relation.