Self-Powered 2D Material-Based pH Sensor and Photodetector Driven by Monolayer MoSe2 Piezoelectric Nanogenerator

Oxygen-Doped 2D In2Se3 Nanosheets with Extended In-Plane Lattice Strain for Highly Efficient Piezoelectric Energy Harvesting

With the emergence of electromechanical devices, considerable efforts have been devoted to improving the piezoelectricity of 2D materials. Herein, an anion-doping approach is proposed as an effective way to enhance the piezoelectricity of α-In2Se3 nanosheets, which has a rare asymmetric structure in both the in-plane and out-of-plane directions. As the O2 plasma treatment gradually substitutes selenium with oxygen, it changes the crystal structure, creating a larger lattice distortion and, thus, an extended dipole moment. Prior to the O2 treatment, the lattice extension is deliberately maximized in the lateral direction by imposing in situ tensile strain during the exfoliation process for preparing the nanosheets. Combining doping and strain engineering substantially enhances the piezoelectric coefficient and electromechanical energy conversion. As a result, the optimal harvester with a 0.9% in situ strain and 10 min plasma exposure achieves the highest piezoelectric energy harvesting values of ≈13.5 nA and ≈420 µW cm-2 under bending operation, outperforming all previously reported 2D materials. Theoretical estimation of the structural changes and polarization with gradual oxygen substitution supports the observed dependence of the electromechanical performance.

Tunable WSe2-MoSe2 Lateral Heterojunction Photodetector Based on Piezoelectric and Flexoelectric Effects

Two-dimensional transition metal dichalcogenides (TMDs) with piezoelectric effects are ideal materials for future wearable devices. While enhancing the piezoelectric performance by forming vertical heterojunctions, shortcomings such as contamination at the heterojunction interface and limited built-in electric field width have been noticed. In this work, a lateral heterojunction of monolayer WSe2-MoSe2 with type-II band alignment was employed to amplify the electromechanical optoelectronic efficiency. The considerable built-in field width (BFW) in the lateral heterojunction facilitates rapid separation of carriers. The lattice mismatch induced a flexoelectric effect during the lateral heterojunction growth. The flexoelectric and piezoelectric effects under external strain can regulate the photodetector performance of the device. Under the compressive strain of -0.93%, the photocurrent increased 9.1 times compared to the tensile strain of 0.47%. Flexoelectric effect can reduce the dark current under no external strain. This work reveals the roles of flexoelectric and piezoelectric effects in enhancing photoelectric conversion, suggesting lateral heterojunction devices may be applied in the field of flexible low-light detection.

Engineering piezoelectricity at vdW interfaces of quasi-1D chains in 2D Tellurene

Low-dimensional piezoelectrics have drawn attention to the realization in nano-scale devices with high integration density. A unique branch of 2D Tellurene bilayers formed of weakly interacting quasi-1D chains via van der Waals forces is found to exhibit piezoelectricity due to the semiconducting band gap and spatial inversion asymmetry. Various bilayer stackings are systematically examined using density functional theory, revealing optimal piezoelectricity when dipole arrangements are identical in each layer. Negative piezoelectricity has been observed in two of the stackings AA' and AA″ while other two stackings exhibit the usual positive piezoelectric effect. The layer-dependent 2D piezoelectricity (∣e222D ∣) increases with an increasing number of layers in contrast to the odd-even effect observed in h-BN and MoS2. Notably, the piezoelectric effect is observed in even-layered structures due to the homogeneous stacking in multilayers. Strain is found to enhance in-plane piezoelectricity by 4.5 times (-66.25 × 10-10C m-1at -5.1% strain) due to the increasing difference in Born effective charges of positively and negatively charged Te-atoms under compressive biaxial strains. Moreover, out-of-plane piezoelectricity is induced by applying an external electric field, thus implying Tellurene is a promising candidate for piezoelectric sensors.

Recent advances in 2D transition metal dichalcogenide-based photodetectors: a review

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have emerged as a highly promising platform for the development of photodetectors (PDs) owing to their remarkable electronic and optoelectronic properties. Highly effective PDs can be obtained by making use of the exceptional properties of 2D materials, such as their high transparency, large charge carrier mobility, and tunable electronic structure. The photodetection mechanism in 2D TMD-based PDs is thoroughly discussed in this article, with special attention paid to the key characteristics that set them apart from PDs based on other integrated materials. This review examines how single TMDs, TMD-TMD heterostructures, TMD-graphene (Gr) hybrids, TMD-MXene composites, TMD-perovskite heterostructures, and TMD-quantum dot (QD) configurations show advanced photodetection. Additionally, a thorough analysis of the recent developments in 2D TMD-based PDs, highlighting their exceptional performance capabilities, including ultrafast photo response, ultrabroad detectivity, and ultrahigh photoresponsivity, attained through cutting-edge methods is provided. The article conclusion highlights the potential for ground-breaking discoveries in this fast developing field of research by outlining the challenges faced in the field of PDs today and providing an outlook on the prospects of 2D TMD-based PDs in the future.

2D Materials in Flexible Electronics: Recent Advances and Future Prospectives

Flexible electronics have recently gained considerable attention due to their potential to provide new and innovative solutions to a wide range of challenges in various electronic fields. These electronics require specific material properties and performance because they need to be integrated into a variety of surfaces or folded and rolled for newly formatted electronics. Two-dimensional (2D) materials have emerged as promising candidates for flexible electronics due to their unique mechanical, electrical, and optical properties, as well as their compatibility with other materials, enabling the creation of various flexible electronic devices. This article provides a comprehensive review of the progress made in developing flexible electronic devices using 2D materials. In addition, it highlights the key aspects of materials, scalable material production, and device fabrication processes for flexible applications, along with important examples of demonstrations that achieved breakthroughs in various flexible and wearable electronic applications. Finally, we discuss the opportunities, current challenges, potential solutions, and future investigative directions about this field.

First-principles study of the effect of doping on the optoelectronic properties of defective monolayers of MoSe2

CONTEXT

In this paper, the structural stability, electronic structure, and optical properties of monolayer MoSe2 doped with C, O, Si, S, and Te atoms, respectively, under defective conditions are investigated based on first principles. It is found that the system is more structurally stable when defecting a single Se atom as compared to defecting a single Mo or two Se atoms. The electronic structure analysis of the system reveals that intrinsic MoSe2 is a direct bandgap semiconductor. The bandgap value of the system decreases with a single Se atom defect and introduces two new impurity energy levels in the conduction band. The defective systems doped with C and Si atoms all exhibit P-type doping. The total density of states of intrinsic MoSe2 is mainly contributed by the Mo-d and Se-p orbitals, and new density of state peaks appears near the conduction band after the defects of Se atoms. The total density of states of the defective system doped by each atom is mainly contributed by Mo-d, Se-p, and the result of the p orbital contribution of each dopant atom. By analyzing the dielectric function of each system, it is found that the intrinsic MoSe2 has the lowest static permittivity and the C-doped defect system has the highest static permittivity, which reaches 21.42. The C- and Si-doped defect systems are the first to start absorbing the light, and the intrinsic MoSe2 absorbs the light later, with its absorption edge starting at 1.25 eV. In the visible range, the reflection peaks of the systems move toward the high-energy region and the blue-shift phenomenon occurs. It is hoped that applying modification means to modulate the physical properties of the two-dimensional materials will provide some theoretical basis for broadening the application of monolayer MoSe2 in the field of optoelectronic devices.

METHODS

This study utilizes the first principle computational software package MS8.0 (Materials studio8.0) under density functional theory (DFT). The exchange-correlation potential (GGA-PBE) is described by the Perdew-Burke-Ernzerhof correlation function in CASTEP, and the potential function adopts the ultrasoft pseudopotential in the inverse space formulation. The plane wave truncation energy Ecut is set to 400 eV, the K-point is taken as 5 × 5 × 1, and the force convergence criterion is 0.05 eV/Å. The convergence accuracy of the total energy of the system is less than 1.0 × 10-5 eV/atom, the tolerance shift is less than 0.002 Å, and the stress deviation is less than 0.1 GPa. The vacuum layer is taken as 15 Å, which is intended to minimize the interlayer force. The vacuum layer was set to 15 Å to avoid the effect of layer-to-layer interaction forces in the crystal cell.

Self-Charging Piezo-Supercapacitor: One-Step Mechanical Energy Conversion and Storage

With the contemplations of ecological and environmental issues related to energy harvesting, piezoelectric nanogenerators (PNGs) may be an accessible, sustainable, and abundant elective wellspring of energy in the future. The PNGs' power output, however, is dependent on the mechanical energy input, which will be intermittent if the mechanical energy is not continuous. This is a fatal flaw for electronics that need continuous power. Here, a self-charging flexible supercapacitor (PSCFS) is successfully realized that can harvest sporadic mechanical energy, convert it to electrical energy, and simultaneously store power. Initially, chemically processed multimetallic oxide, namely, copper cobalt nickel oxide (CuCoNiO₄) is amalgamated within the poly(vinylidene fluoride) (PVDF) framework in different wt % to realize high-performance PNGs. The combination of CuCoNiO₄ as filler creates a notable electroactive phase inside the PVDF matrix, and the composite realized by combining 1 wt % CuCoNiO₄ with PVDF, coined as PNCU 1, exhibits the highest electroactive phase (>86%). Under periodic hammering (∼100 kPa), PNGs fabricated with this optimized composite film deliver an instantaneous voltage of ∼67.9 V and a current of ∼4.15 μA. Furthermore, PNG 1 is ingeniously integrated into a supercapacitor to construct PSCFS, using PNCU 1 as a separator and CuCoNiO₄ nanowires on carbon cloth (CC) as the positive and negative electrodes. The self-charging behavior of the rectifier-free storage device was established under bending deformation. The PSCFS device exhibits ∼845 mV from its initial open-circuit potential ∼35 mV in ∼220 s under periodic bending of 180° at a frequency of 1 Hz. The PSCFS can power up various portable electronic appliances such as calculators, watches, and LEDs. This work offers a high-performance, self-powered device that can be used to replace bulky batteries in everyday electronic devices by harnessing mechanical energy, converting mechanical energy from its environment into electrical energy.

Piezoelectric 1T Phase MoSe2 Nanoflowers and Crystallographically Textured Electrodes for Enhanced Low-Temperature Zinc-Ion Storage

Transition metal dichalcogenides (TMDs) are regarded as promising cathode materials for zinc-ion storage owing to their large interlayer spacings. However, their capabilities are still limited by sluggish kinetics and inferior conductivities. In this study, a facile one-pot solvothermal method is exploited to vertically plant piezoelectric 1T MoSe₂  nanoflowers on carbon cloth (CC) to fabricate crystallographically textured electrodes. The self-built-in electric field owing to the intrinsic piezoelectricity during the intercalation/deintercalation processes can serve as an additional piezo-electrochemical coupling accelerator to enhance the migration of Zn²⁺ . Moreover, the expanded interlayer distance (9-10 Å), overall high hydrophilicity, and conductivity of the 1T phase MoSe₂  also promoted the kinetics. These advantages endow the tailored 1T MoSe₂ /CC nanopiezocomposite with feasible Zn²⁺ diffusion and desirable electrochemical performances at room and low temperatures. Moreover, 1T MoSe₂ /CC-based quasi-solid-state zinc-ion batteries are constructed to evaluate the potential of the proposed material in low-temperature flexible energy storage devices. This work expounds the positive effect of intrinsic piezoelectricity of TMDs on Zn²⁺ migration and further explores the availabilities of TMDs in low-temperature wearable energy-storage devices.

From Piezoelectric Nanogenerator to Non-Invasive Medical Sensor: A Review

Piezoelectric nanogenerators (PENGs) not only are able to harvest mechanical energy from the ambient environment or body and convert mechanical signals into electricity but can also inform us about pathophysiological changes and communicate this information using electrical signals, thus acting as medical sensors to provide personalized medical solutions to patients. In this review, we aim to present the latest advances in PENG-based non-invasive sensors for clinical diagnosis and medical treatment. While we begin with the basic principles of PENGs and their applications in energy harvesting, this review focuses on the medical sensing applications of PENGs, including detection mechanisms, material selection, and adaptive design, which are oriented toward disease diagnosis. Considering the non-invasive in vitro application scenario, discussions about the individualized designs that are intended to balance a high performance, durability, comfortability, and skin-friendliness are mainly divided into two types: mechanical sensors and biosensors, according to the key role of piezoelectric effects in disease diagnosis. The shortcomings, challenges, and possible corresponding solutions of PENG-based medical sensing devices are also highlighted, promoting the development of robust, reliable, scalable, and cost-effective medical systems that are helpful for the public.

2D Transition Metal Dichalcogenide with Increased Entropy for Piezoelectric Electronics

Piezoelectricity in 2D transition metal dichalcogenides (TMDs) has attracted considerable interest because of their excellent flexibility and high piezoelectric coefficient compared to conventional piezoelectric bulk materials. However, the ability to regulate the piezoelectric properties is limited because the entropy is constant for certain binary TMDs other than multielement ones. Herein, in order to increase the entropy, a ternary TMDs alloy, Mo_{1- x} W_x S₂ , with different W concentrations, is synthesized. The W concentration in the Mo_{1- x} W_x S₂ alloy can be controlled precisely in the low-supersaturation synthesis and the entropy can be tuned accordingly. The Mo_0.46 W_0.54 S₂ alloy (x = 0.54) has the highest configurational entropy and best piezoelectric properties, such as a piezoelectric coefficient of 4.22 pm V^-1 and a piezoelectric output current of 150 pA at 0.24% strain. More importantly, it can be combined into a larger package to increase the output current to 600 pA to cater to self-powered applications. Combining with excellent mechanical durability, a mechanical sensor based on the Mo_0.46 W_0.54 S₂ alloy is demonstrated for real-time health monitoring.

Nanoampere-Level Piezoelectric Energy Harvesting Performance of Lithography-Free Centimeter-Scale MoS2 Monolayer Film Generators

2D transition-metal dichalcogenides have been reported to possess piezoelectricity due to their lack of inversion symmetry; thus, they are potentially applicable as electromechanical energy harvesters. Herein, the authors propose a lithography-free piezoelectric energy harvester composed of centimeter-scale MoS₂ monolayer films with an interdigitated electrode pattern that is enabled only by the large scale of the film. High-quality large-scale synthesis of the monolayer films is conducted by low-pressure chemical vapor deposition with the assistance of an unprecedented Na₂ S promoter. The extra sulfur supplied by Na₂ S critically passivates the sulfur vacancies. The energy harvester having a large active area of ≈18.3 mm² demonstrates an unexpectedly high piezoelectric energy harvesting performance of ≈400.4 mV and ≈40.7 nA under a bending strain of 0.57%, with the careful adjustment of side electrodes along the zigzag atomic arrays in the two dominant domain structure. Nanoampere-level harvesting has not yet been reported with any 2D material-based harvester.

Effect of cobalt phosphide (CoP) vacancies on its hydrogen evolution activity via water splitting: a theoretical study

Defect engineering plays an important role in improving the performance of catalysts. To clarify the roles of Co and P vacancies in CoP for water splitting, a theoretical study based on density functional theory was carried out in this paper. The geometric and electronic structures, activity and stability of the CoP (101)B surface, CoP (101)B with the Co vacancy (Co_vac) and the P vacancy (P_vac) are investigated. The results indicate that the CoP (101)B surface with P_vac and Co_vac can enhance the electron transfer to the surface. The P_vac will upward shift the Co d-band center near the vacancy site, which promotes the adsorption of H on the Co atom. As a result, the bridge Co-Co sites near the vacancy become the active sites for the hydrogen evolution reaction (HER) (ΔG_H* = 0.01 eV). The loss of the Co atom also results in an upward shift of its d-band center, which will enhance the H adsorption on the adjacent Co sites. The unevenly distributed electrons due to the presence of vacancies on the surface cause spontaneous dissociation of H₂O molecules. Furthermore, the thermodynamic analysis and surface energy find that the CoP (101)B and (101)B facets with Co_vac and P_vac present good stability. The current work has shed light onto the mechanism of water splitting on the surface of phosphide with vacancies. Our study suggests that engineering vacancies on CoP is a feasible route to improve its catalytic activity.

Piezoelectric effect enhanced photocatalysis in environmental remediation: State-of-the-art techniques and future scenarios

Photocatalysis has been widely used as an advanced oxidation process to control pollutants effectively. However, environmental photocatalysis' decontamination efficiency is restricted to the photogenerated electron-hole pairs' rapid recombination. Recently, emerging investigations have been directed to generate internal electric field by piezoelectric effect to enhance the separation efficiency of photogenerated charge carriers for better photocatalytic performance; however, there are still huge knowledge gaps on the rational application of piezo-photocatalysis in environmental remediation and disinfection. Thus, we have conducted a comprehensive review to better understand the physicochemical properties of piezoelectric materials (non-centrosymmetric crystal structures, piezoelectric coefficient, Young's modulus, and etc.) and current study states. We also elucidated the strategy of piezo-photo catalysis system constructions (mono-component, core-shell structure, and etc.) and underlying mechanisms of enhanced remediation performance. Addressing the current challenges and future scenarios (degradation of organic pollutants, disinfection, and etc.), the present review would shed light on the advanced wastewater treatment development towards sustainable control of emerging containments.

Synergetic contribution of enriched selenium vacancies and out-of-plane ferroelectric polarization in AB-stacked MoSe2 nanosheets as efficient piezocatalysts for TC degradation

Novel MoSe2 piezocatalysts with surface selenium vacancies and out-of-plane ferroelectric polarization exhibit ultrafast degradation of the antibiotic tetracycline.

Recent trends in 2D materials and their polymer composites for effectively harnessing mechanical energy

Self-powered wearable devices, with the energy harvester as a source of energy that can scavenge the energy from ambient sources present in our surroundings to cater to the energy needs of portable wearable electronics, are becoming more widespread because of their miniaturization and multifunctional characteristics. Triboelectric and piezoelectric nanogenerators are being explored to harvest electrical energy from the mechanical vibrations. Integration of these two effects to fabricate a hybrid nanogenerator can further enhance the output efficiency of the nanogenerator. Here, we have discussed the importance of 2D materials which plays an important role in the fabrication of nanogenerators because of their distinct characteristics, such as, flexibility, mechanical stability, nontoxicity, and biodegradability. This review mainly emphasizes the piezoelectric, triboelectric, and hybrid nanogenerator based on the 2D materials and their van der Waals heterostructure, as well as the effect of polymer-2D composite on the output performance of the nanogenerator.

Self-Poled Poly(vinylidene fluoride)/MXene Piezoelectric Energy Harvester with Boosted Power Generation Ability and the Roles of Crystalline Orientation and Polarized Interfaces

Micropiezoelectric devices have become one of the most competitive candidates for use in self-powered flexible and portable electronic products because of their instant response and mechanic-electric conversion ability. However, achievement of high output performance of micropiezoelectric devices is still a significant and challenging task. In this study, a poly(vinylidene fluoride) (PVDF)/MXene piezoelectric microdevice was fabricated through a microinjection molding process. The synergistic effect of both an intense shear rate (>10⁴ s^-1) as well as numerous polar C-F functional groups in MXene flakes promoted the formation of β-form crystals of PVDF in which the crystallinity of β-form could reach as high as 59.9%. Moreover, the shear-induced shish-kebab crystal structure with a high orientation degree (f_h = ∼0.9) and the stacked MXene acted as the driving force for the dipoles to regularly arrange and produce a self-polarizing effect. Without further polarization, the fabricated piezoelectric microdevices exhibited an open-circuit voltage of 15.2 V and a short-circuit current of 497.3 nA, under optimal conditions (400 mm s^-1 and 1 wt % MXene). Impressively, such piezoelectric microdevices can be used for energy storage and for sensing body motion to monitor exercise, and this may have a positive impact on next-generation smart sports equipment.

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. ACS Nano, 2018, 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. Inspired by this experiment, a new hexagonal buckled two-dimensional (2D) semiconductor, ZnTe, and its iso-electronic partner, CdTe, are proposed herewith. These 2D materials show a strong spin-orbit coupling (SOC), which is evidenced by a large Rashba constant of 1.06 and 1.27 eV·Å, respectively, in ZnTe and CdTe monolayers. Moreover, these Rashba semiconductors exhibit a giant out-of-plane piezoelectric coefficient (d₃₃) = 88.68 and 172.61 pm/V, and can thereby generate a high piezo potential for gating purposes in spin field-effect transistors (spin-FETs). While the low elastic stiffness implies the mechanical flexibility or stretchability in these monolayers. The Rashba constants are found to be effectively modulated via external perturbations, such as strain and electric field. The wide band gap provides ample room for modulation in its electronic properties via external perturbations. Such scope is severely limited in previously reported narrow band gap Rashba semiconductors. The fascinating results found in this work indicate their great potential for applications in next-generation self-powered flexible-piezo-spintronic devices. Moreover, a new class of hexagonal buckled ZnX (X: S, Se, or Te) monolayers is proposed herein based on their previously synthesized bulk counterparts, while their electronic, mechanical, piezoelectric, and thermal properties have been thoroughly investigated using the state-of-art density functional theory (DFT).

Enhanced Piezoelectric Output Performance of the SnS2/SnS Heterostructure Thin-Film Piezoelectric Nanogenerator Realized by Atomic Layer Deposition

Recently, the inherent piezoelectric properties of the 2D transition-metal dichalcogenides (TMDs) tin monosulfide (SnS) and tin disulfide (SnS₂) have attracted much attention. Thus the piezoelectricity of these materials has been theoretically and experimentally investigated for energy-harvesting devices. However, the piezoelectric output performance of the SnS₂- or SnS-based 2D thin film piezoelectric nanogenerator (PENG) is still relatively low, and the fabrication process is not suitable for practical applications. Here we report the formation of the SnS₂/SnS heterostructure thin film for the enhanced output performance of a PENG using atomic layer deposition (ALD). The piezoelectric response of the heterostructure thin film was increased by ∼40% compared with that of the SnS₂ thin film, attributed to large band offset induced by the heterojunction formation. Consequently, the output voltage and current density of the heterostructure PENG were 60 mV and 11.4 nA/cm² at 0.6% tensile strain, respectively. In addition, thickness-controllable large-area uniform thin-film deposition via ALD ensures that the reproducible output performance is achieved and that the output density can be lithographically adjusted depending on the applications. Therefore, the SnS₂/SnS heterostructure PENG fabricated in this work can be employed to develop a flexible energy-harvesting device or an attachable self-powered sensor for monitoring pulse and human body movement.

Single-Crystalline Silicon Frameworks: A New Platform for Transparent Flexible Optoelectronics

Single-crystalline silicon (sc-Si) is the dominant semiconductor material for the modern electronics industry. Despite their excellent photoelectric and electronic properties, the rigidity, brittleness, and nontransparency of commonly used silicon wafers limit their application in transparent flexible optoelectronics. In this study, a new type of Si microstructure, named single-crystalline Si frameworks (sc-SiFs), is developed, through a combination of wet-etching and microfabrication technologies. The sc-SiFs are self-supported, flexible, lightweight, tailorable, and highly transparent. They can withstand a small bending radius of less than 0.5 mm and have a transparency of up to 96% in all wavelength ranges, owing to the hollowed-out framework structures. Thus, the sc-SiFs provide a new platform for high-performance transparent flexible optoelectronics. Taking transparent flexible photodetectors (TFPDs) as an example, substrate-free and self-driven TFPDs are achieved based on the sc-SiFs. The devices exhibit superior performance compared to other reported TFPDs and reveal the great potential for integrated optoelectronic applications. The development of sc-SiFs paves the way toward the fabrication of high-performance transparent flexible devices for a host of applications, including e-skins, the Internet of Things, transparent flexible displays, and artificial visual cortexes.

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 0.63 eV Å that is tunable to the extent of ±0.2 eV Å via biaxial strain. Also, owing to its broken inversion symmetry and buckling geometry, MgTe has a very large in-plane as well as out-of-plane piezoelectric coefficient. These results indicate its prospects for serving as a channel semiconducting material in self-powered piezo-spintronic devices. Furthermore, a prototype for a digital logic device can be envisioned using the ac pulsed technology via a perpendicular electric field. Heat transport is significantly suppressed in these monolayers as observed from their intrinsic low lattice thermal conductivity at room temperature: MgS (9.32 W m-1 K-1), MgSe (4.93 W m-1 K-1) and MgTe (2.02 W m-1 K-1). Further studies indicate that these monolayers can be used as photocatalytic materials for the simultaneous production of hydrogen and oxygen on account of having suitable band edge alignment and high charge carrier mobility. This work provides significant theoretical insights into both the fundamental and applied properties of these new buckled MgX monolayers, which are highly suitable for futuristic applications at the nanoscale in low-power, self-powered multifunctional electronic and spintronic devices and solar energy harvesting.