Standard bulk thermoelectrics are limited by the interdependence of the thermoelectric properties (Seebeck coefficient, thermal conductivity, and electrical conductivity), requiring an comprehensive review of two-dimensional (2D) quantum confinement and atomic arrangements in tellurides to decouple these parameters for next-gen material-design roadmap. This review study employs a comprehensive meta-analysis of the literature, extracting and standardizing data from various DFT and semi-classical transport simulations to assess the influence of stoichiometry and stacking sequences on performance. This review identifies complex crystal structures (ABC-stacked AB2 and quaternary compounds) as the favorable features to achieve high ZT values, because of mixed flat-dispersive bands and strong anharmonic phonon scattering. Structural complexity and Te-dimer states also facilitate bonding heterogeneity, which helps minimize lattice thermal conductivity while maintaining high carrier mobility.

This study employs density functional theory to systematically investigate the pressure-dependent structural, electronic, and thermoelectric properties of bulk and monolayer InSiTe3. The (0001) surface exhibits superior stability with formation energy 0.27 eV/& Aring;(2) lower than alternative crystallographic orientations. Both configurations demonstrate semiconductor-to-metal transitions above 5 GPa, driven by In -> Si charge transfer mediated through Te bridges, with silicon attaining anionic character in the metallic phase. Remarkably, monolayer InSiTe3 achieves near-unity thermoelectric figure of merit (ZT approximate to 1) at 300 K through optimized carrier mobility (similar to 10(1)(6) 1/Omega ms) and ultralow thermal conductivity (kappa/tau = 4.05 x 10(-8) W/mKs), outperforming bulk counterparts (ZT approximate to 0.3) by 3.3 times. Pressure application induces critical bond population inversion in bulk systems while preserving monolayer electronic structure integrity. The material demonstrates exceptional surface passivation stability, with -OH adsorption requiring 3.45 eV kinetic barriers - triple MoS2 ' s value - due to Te 5p orbital-mediated transition state stabilization. These findings establish InSiTe3 as a dual-function platform for pressure-adaptive thermoelectrics and robust optoelectronic coatings, contingent on operational pressure constraints below the metallic transition threshold.

A lot of experimental studies are conducted on theoretically predicted thermoelectric 2D materials. Such materials can pave the way for charging ultra-thin electronic devices, self-charging wearable devices, and medical implants. This study systematically explores the thermoelectric attributes of bulk and 2D nanostructured Tin Telluride (SnTe), employing experimental investigations and theoretical analyses based on semiclassical Boltzmann transport theory. The bulk SnTe is synthesized through flame melting, while the 2D SnTe is produced via liquid phase exfoliation. The comprehensive assessment of thermoelectric properties integrated experimental measurements utilizing a Physical Property Measurement System and theoretical calculations from the BoltzTraP code. Experimental thermoelectric studies show a high ZT of 0.17 for 2D SnTe when compared to bulk (0.005) at room temperature. This rise in ZT is due to the high Seebeck coefficient and low thermal conductivity of nanostructured 2D SnTe. Density functional theory (DFT) studies reveal the contribution of the density of states (DOS) and energy bandgap in enhancing the Seebeck coefficient and lowering thermal conductivity by interface scattering.

Objectives: The effect of homoeopathic potentization increases with dilution. The physical and chemical properties of the homoeopathy solution change as a function of the concentration of nanoparticles (NPs). The succussion process is also vital in homoeopathy. However, none of these factors, along with the container of the medicine, have been well-researched to date. Material and Methods: We studied the systematic ultra-low dilution (up to 10 200 times) effect of homoeopathic remedy of Aurum Metallicum (Gold) NP colloidal solution to determine the mechanism of colloidal formation in such extreme dilution. Several material characterizations were also performed to consolidate our results. Results: Optical spectroscopy confirmed the presence of NPs with narrow size distribution and high surface activity in higher dilution (up to 10 200 times) homoeopathic solution. The particle size analysis of the serially diluted solution showed that the size distribution becomes narrow with increasing dilution. Transmission electron microscopy confirmed the presence of NPs in solutions up to 10 200 times dilution. Conclusion: The process of dilution introduces an active hydrocarbon layer on these NPs. The experimental study further confirmed theoretical calculations. The understanding of such extreme dilutions can be utilized in biomedical applications, especially in homoeopathic medicine.

2D FeS2 has the potential to convert ambient radiofrequency electromagnetic radiation signals into usable energy, which can be utilized to power portable and wearable electronic devices.

Earth’s abundant lead sulfide (PbS) is gaining increasing attention for its thermoelectric properties, particularly in converting heat into electricity at room to mid-temperatures. While several studies have reported enhancements in the thermoelectric figure of merit, commonly referred to as the figure of merit, ZT, for bulk PbS through alloying, its high lattice thermal conductivity significantly limits overall performance. In this study, we present the synthesis and thermoelectric characterization of liquid phase exfoliated 2D PbS, highlighting its improved figure of merit across a range of temperatures. Our measurements indicate a Seebeck coefficient of − 275 µV/K and a high electrical conductivity of 2.7 KS/m, yielding an enhanced figure of merit, ZT, of approximately 0.8 at 550 K. Furthermore, density functional theory (DFT) calculations validate the thermoelectric mechanisms in both bulk and 2D PbS, revealing weak electron–phonon coupling in the 2D form, which contributes to its superior thermoelectric performance. Therefore, 2D PbS holds promise for applications in portable and wearable electronics.

This paper demonstrates the exfoliation of naturally occurring silicates into two-dimensional structures. Moving the d-silicate device repeatedly in a vertical direction causes it to react robotically and generate up to ∼400 mV of voltage.

As a natural polymer, cellulose is abundant, low-cost,robust,and biodegradable and can be chemically modified. This work exploresthe enhancement of mechanical, thermal, and flexoelectric propertiesof three-dimensional (3D)-printed carboxymethyl cellulose (CMC) dueto the addition of mechanically exfoliated hexagonal boron nitride(hBN). hBN was observed to act as a rheology modifier, and CMC reinforcedwith 2% hBN exhibited the maximum apparent viscosity of 12.24 Pa & BULL;sat a shear rate of 100 s(-1). The 0.5% hBN/CMC filmexhibited the highest mechanical and thermal stability. A flexoelectricenergy harvester was fabricated out of 3D-printed hBN/CMC compositesto test the effectiveness of strain-induced charge production. Byvarying the load resistance and applied pressure, we were able tomeasure the voltage and current flowing through the device. We foundthat a load resistance of 180 k & omega; connected across a 2% hBN/CMCdevice resulted in the highest power delivery of 5.5 nW. When mechanicalstrain is applied, a charge state fluctuation and spontaneous polarizationin the hBN/CMC matrix are seen. This phenomenon can be explained basedon the flexoelectric energy-harvesting mechanism, supported by densityfunctional theory (DFT) calculations.

Two-dimensional (2D) materials are increasingly beingused as detectorsand are gaining popularity due to the advantage of tunability of theirelectrical and thermal properties. Certain non-centrosymmetric materialsexhibit a property known as pyroelectricity, which can be utilizedto detect infrared (IR) radiation. On the other hand, the pyroelectriceffect can be induced in centrosymmetric materials by making themreact to external stimuli that break up their symmetry. Here, we reportthe pyroelectric behavior of a centrosymmetric 2D SiTe2 by inducing interface polarization in a Schottky junction. For thisbulk, SiTe2 was synthesized via induction melting and its2D counterpart via liquid-phase exfoliation. A pyroelectric photodetectorin Au/p-SiTe2/ITO configuration was fabricated. The electricalstudies confirm the formation of a Schottky junction. The 2D SiTe2-based pyroelectric detector exhibited a high pyroelectriccoefficient of 3.73 mC/m(2) K and a good responsivity of3.9 x 10(5) Jones. The obtained pyroelectric coefficientusing 2D SiTe2 was remarkably superior to that of conventionalbulk materials. This enhanced property arises from the combined effectof the two-dimensional nature of the material and the induced interfacepolarization in the device. We employed density functional theoryto support our experimental observations. The performance resultssuggest that 2D SiTe2 could be a benchmark candidate forultrafast pyroelectric detectors.

The advancements in 2D materials have opened a plethora of portable, wearable electronic devices. However, their charging methods still confine to plug and charge mode. Considerable efforts have been made in self-powered energy harvesting using piezoelectric, thermoelectric and photovoltaics. However, with the advent of wireless technology, there is a significant demand for wireless-powered devices such as the Internet of Things (IoT) sensors, cell phones and other low-power devices. Hence, radio frequency (RF) energy harvesting can be employed in such scenarios since they can deliver power wirelessly using ambient RF energy. This work demonstrates the synthesis of 2D FeS2 from naturally available earth-abundant pyrite and fabricates a crystal-radio device for RF energy harvesting. The device operated in the commercial FM broadband (88–108 MHz) and the very high frequency (VHF) band up to 170 MHz. A practical demonstration of RF energy harvesting was done by charging a supercapacitor to 1.5V in 20 seconds and illuminating an LED within a range of 1m. Density functional theory (DFT) calculations were performed to support the mechanism of 2D FeS2 for RF applications. The experimental and theoretical studies conclude that 2D FeS2 is a noteworthy material for RF energy-based devices.

Two-dimensional (2D) materials with high surface activity can be utilized for harvesting energy from small mechanical sources using flexoelectricity. In the present work, we have synthesized an atomically thin 2D spinel MgCr2O4 by a liquid-phase exfoliation process, and characterization shows the preferential exfoliation along the (111) plane with low formation energy. The fabricated flexoelectric device produces an electrical response up to-3 V (peak-to-peak voltage) upon pressing and releasing the cell with-0.98 N force. Furthermore, the energy harvesting properties of 2D MgCr2O4 are explored by combining bending with other sources of external energy, with applied varying magnetic flux (Vmax 1/4-2.6 V) and temperature with 0.9 N force (Vmax 1/4-18 V). Our calculations determine that 2D MgCr2O4 has a flexoelectric coefficient of approximately mXZXZ 1/4 0.005 nC/m. Overall, the results indicate that 2D MgCr2O4 is a very promising material for the next generation of self-powered wearable electronics and energy harvesting.& COPY; 2023 Elsevier Ltd. All rights reserved.

Radiofrequency (RF) energy harvesting is receiving increased attention in today's digital era due to its potential to replace or improve the longevity of energy storage devices in low-power IoT devices. RF energy is available in the ambient environment, but efficient devices are still not commonly known for RF energy harvesting applications. Here, the main goal is to develop an RF energy harvesting device using multi-layered two-dimensional (2D) galena (PbS). A Schottky diode is fabricated by using 2D galena. RF energy harvesting is demonstrated using a handheld radio transceiver with a carrier frequency of 140-170 MHz. The device extracts RF energy and produces an output DC voltage of a maximum of 1.8 volts and a corresponding output power of 38 mW at 150 MHz, and lights up an LED within a range of 100 cm. At 150 MHz, the device's power conversion efficiency is found to be 19%. DFT calculations support the experimental observations of energy harvesting using 2D galena. The performance results show that 2D galena is a promising material for RF energy harvesting devices.

Continuous health monitoring through sensitive physiological signals (using a wearable device) is crucial for the early detection of heart diseases and breathing problems. Here, we have developed a flexible hBN/cotton hybrid device that can detect minor signals such as heartbeat and breathed-out air pressure. Systematic observation of the real-time motion sensing showed a peak-to-peak voltage output of ∼1.5 V for each heart rate pulse. The as-fabricated device showed a high voltage output of up to ∼10 V upon applying a pressure of ∼3 MPa. The FTIR results and DFT calculation suggested a chemical interaction between hBN and cellulose, giving rise to flat band characteristics and partially filled σ-bonding (sp2) hybridization. The atomic-scale chemical interface between atomically thin hBN and surface functional groups present on cotton resulted in charge localization and enhanced output voltage. An hBN/cotton hybrid device can bring new insights and opportunities to develop a self-charging and health-monitoring energy-harvesting cloth.

Niobium carbide (NbCx)-based materials have garnered significant attention in energy- and power-based applications. The physiochemistry-mediated preparation of two-dimensional (2D) NbC structures is often limited by extremely high-temperature and -pressure reaction conditions conjugated with toxic chemicals. In the present study, a unique biobased strategy, utilizing a solid-gas reaction, is developed, which involves the carburization of niobium salt (NbCl5)-based oxides using methane (CH4) and other metabolic gases produced by methanogen syntrophic culture. Thermodynamic calculations were performed to comprehend the reaction conditions of the biosystem during NbC formation. The bioprepared NbC sheets were found to be similar to 10 nm thin and were studied for their potential in energy harvesting applications. The strain-induced charge generation was evaluated by fabricating a flexoelectric energy harvester with NbC sheets as a flexoelectric material. The maximum power output was similar to 2.64 mW/m(2) for 8.8 N applied force. We obtained clear evidence of flexoelectricity in NbC using Raman analysis. Finally, external pressure-, magnetic force-, and temperature-dependent responses were recorded to visualize the practical applications of NbC-based flexible flexoelectric nanogenerators in wearable electronics and sensing.

In the last decade, the materials community has been exploring new 2D materials (graphene, metallene, TMDs, TMCs, MXene, among others) that have unique physical and chemical properties. Recently, a new family of 2D materials, the so-called 2D silicates, have been proposed. They are predicted to exhibit exciting properties (such as high catalytic activity, piezoelectricity, and 2D magnetism). In the current work, we demonstrate a generic approach to the synthesis of large-scale 2D silicates from selected minerals, such as Diopside (d). Different experimental techniques were used to confirm the existence of the 2D structures (named 2D-d-silicates). DFT simulations were also used to gain insight into the structural features and energy harvesting mechanisms (flexoelectric response generating voltage up to 10 V). The current approach is completely general and can be utilized for large-scale synthesis of 2D silicates and their derivatives, whose large-scale syntheses have been elusive.

2D materials with high surface activity can be utilized for harvesting energy from small mechanical sources using flexoelectricity. In the present work, we have synthesized an atomically thin two-dimensional (2D) spinel MgCr 2 O 4 by a liquid-phase exfoliation process, and characterization shows the preferential exfoliation along the (111) plane with low formation energy. The fabricated flexoelectric device produces an electrical response up to ~3V upon pressing and releasing the cell with ~0.98N force. Furthermore, the energy harvesting properties of 2D MgCr 2 O 4 are explored by combining bending with other sources of external energy, with applied varying magnetic flux (V max = ~2.6V) and temperature with 0.9N force (V max = ~18V). Density functional theory (DFT) simulations support the experimental observation and explain the mechanism for the source of energy in the 2D form of MgCr 2 O 4 . These results indicate that 2D MgCr 2 O 4 is a very promising material for the next generation of self-powered wearable electronics and energy harvesting.

Atomically thin two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted significant attention owing to their prosperity in material research. The inimitable features of TMDCs triggered the emerging applications in diverse areas. In this review, we focus on the tailored and engineering of the crystal lattice of TMDCs that finally enhance the efficiency of the material properties. We highlight several preparation techniques and recent advancements in compositional engineering of TMDCs structure. We summarize different approaches for TMDCs such as doping and alloying with different materials, alloying with other 2D metals, and scrutinize the technological potential of these methods. Beyond that, we also highlight the recent significant advancement in preparing 2D quasicrystals and alloying the 2D TMDCs with MAX phases. Finally, we highlight the future perspectives for crystal engineering in TMDC materials for structure stability, machine learning concept marge with materials, and their emerging applications.

The facile synthesis of nanocrystalline lead fin tellurium selenium (PbSnTeSe) high entropy alloy (HEA) doped with Bi by mechanical alloying (MA) (5 hrs) and spark plasma sintering (SPS) (11 min) is reported. The first principle approach prediction and experimental validation confess the strong implications of enhanced configurational entropy and band engineering phenomena in nanostructured PbSn0.875TeSeBi0.125 HEA. The approach enables the superior power factor (12.74x10(-4) W/mK(2)) and ultralow thermal conductivity (0.814 W/mK) to explore the superior figure of merit, ZT = 0.71 in PbSn0.875TeSeBi0.125 HEA and compatibility factor (CF) of 3.10 at 623 K.This shows the applaudable enhancement of 154% in ZT than pristine PbSnTeSe HEA (ZT = 0.46).