Increase In Carrier Mobility Research Articles

Highly ordered crystallization of α-FAPbI3 films via homogeneous seeds for efficient perovskite solar cells

Formamidine lead triiodide (FAPbI3) perovskites have become the most promising photovoltaic materials for perovskite solar cells with record power conversion efficiency (PCE). However, random nucleation, phase transition, and lattice defects are still the key challenges limiting the quality of FAPbI3 films. Previous studies show that the introduction or adding of seeds in the precursor is effective to promote the nucleation and crystallization of perovskite films. Nevertheless, the seed-assisted approach focuses on heterogeneous seeds or hetero-composites, which inevitably induce a lattice-mismatch, the generation of strain or defects, and the phase segregation in the perovskite films. Herein, we first demonstrate that high-quality perovskite films are controllably prepared using α- and δ-phases mixed FAPbI3 microcrystal as the homogeneous seeds with the one-step antisolvent method. The partially dissolved seeds with suitable sizes improve the crystallinity of the perovskite film with preferable orientation, improved carrier lifetime, and increased carrier mobility. More importantly, the α-phase-containing seeds promote the formation of α-phase FAPbI3 films, leading to the reduction of residual lattice strain and the suppression of I− ion migration. Besides, the adding of dimethyl 2,6-pyridine dicarboxylate (DPD) into the precursor further suppresses the generation of defects, contributing to the PCE of devices prepared in air ambient being significantly improved to 23.75%, among the highest PCEs for fully air-processed FAPbI3 solar cells. The unpackaged target devices possess a high stability, maintaining 80% of the initial PCE under simulated solar illumination exceeding 800 h.

Boosting Thermoelectric Performance of PbBi2Te4 via Reduced Carrier Scattering and Intensified Phonon Scattering.

Materials with low intrinsic lattice thermal conductivity are crucial in the pursuit of high-performance thermoelectric (TE) materials. Here, the TE properties of PbBi2Te4-xSex (0 ≤ x ≤ 0.6) samples are systematically investigated for the first time. Doping with Se in PbBi2Te4 can simultaneously reduce carrier concentration and increase carrier mobility. The Seebeck coefficient is significantly increased by doping with Se, based on the density functional theory calculation, it is shown to be due to the increased bandgap and electronic density of states. In addition, the lattice strain is enhanced due to the difference in the size of Se and Te atoms, and the multidimensional defects formed by Se doping, such as vacancies, dislocations, and grain boundaries, enhance the phonon scattering and reduce the lattice thermal conductivity by about 37%. Finally, by using Se doping to reduce carrier concentration and thermal conductivity, a large ZTmax = 0.56 (at 574K) is achieved for PbBi2Te3.5Se0.5, which is around 64% larger than those of the PbBi2Te4 pristine sample. This work not only demonstrates that PbBi2Te4 is a potential medium temperature thermoelectric material, but also provides a reference for enhancing thermoelectric properties through defect and energy band engineering.

Improved thermoelectric properties by copolymerization of conducting with insulating monomers on carbon nanotubes

In the present work, development of carbon nanotube (CNT)/poly(conducting-co-insulating monomer) structures was proposed to improve the thermoelectric (TE) performance in CNT/polyaniline (PANI) composites. To check the validity of this idea, we prepared multiwalled carbon nanotube (MWNT)/poly(aniline-co-acrylonitrile) composites by in-situ inverted emulsion copolymerization, and applied secondary doping with camphorsulfonic acid in m-cresol medium prior to the investigation of TE properties. The samples were characterized by FT-IR, UV–Vis, 1H NMR, DSC, GPC, CHNS elemental analysis, intrinsic viscosity, SEM, XRD, electrical resistance, Seebeck coefficient, thickness, and Hall measurements. We report that nitrile groups were hydrolyzed during the polymerization reactions to provide a polymer structure exhibiting aniline, acrylamide, acrylic acid, and glutarimide groups. Further, the poly(aniline-co-acrylonitrile) that prepared in the present work were random copolymers. Importantly, we found that 30 % MWNT/70 % poly(90ANI-co-10AN) composite exhibited a 63 % higher power factor (PF) of 5.48 μW/mK2 (σ: 225 S/cm, S: 15.6 μV/K) at 35 °C than that of 30 % MWNT/70 % PANI, which exhibited a PF of about 3.37 μW/mK2 (σ: 238 S/cm, S: 11.9 μV/K). This was ascribed to the decrease of carrier concentration together with the increase of carrier mobility in the 30 % MWNT/70 % poly(90ANI-co-10AN) composite as compared to the 30 % MWNT/70 % PANI.

Fabrication of highly conducting undoped ZnO ceramics by flash sintering

Highly conducting undoped ZnO ceramics were fabricated by flash sintering using commercial pure ZnO powder as a model system. The flash-sintered samples with diameters of 15 mm and heights of 2 mm exhibited relative densities ranging from 93.6% to 97.1% and room-temperature electrical conductivities between 205 and 590 S/cm. X-ray diffraction and Raman spectra indicated a high concentration of oxygen vacancies and zinc interstitials in the flash-sintered samples, increasing the carrier concentration. Detailed microstructural analyses show that clean grain boundaries and the morphology and distribution of impurities in flash-sintered samples are favorable for improving carrier mobility. Additionally, flash sintering has the advantage of reducing conditions, which reduces acceptor defects at ZnO grain boundaries, lowers Schottky barriers, and increases carrier mobility. The results show that flash sintering can synergistically enhance the carrier concentration and mobility in ZnO ceramics, making it a promising technique for fabricating highly conducting ZnO ceramics.

MoS2 and MoS2-based nanocomposites for enhanced toluene sensing response at room temperature

Nanostructured materials, characterized by their unique physical and chemical attributes at the nanoscale, enable the development of advanced applications due to their distinct size-dependent phenomena and surface properties. Molybdenum disulfide (MoS2) has recently attracted significant attention for room-temperature gas detection due to its large specific surface area, enhanced surface reactivity, and increased carrier mobility. Herein, we report enhanced toluene sensing response of MoS2 and MoS2-based nanocomposites (MoS2-GO and MoS2-Fe3O4) at room temperature. The hydrothermal method was employed to synthesize MoS2-based nanocomposites chemically. Highly selective and sensitive MoS2-based gas sensors were fabricated and applied to enhance room temperature sensing for different concentrations of toluene. The samples MoS2, MoS2-Fe3O4, and MoS2-GO showed good sensing performance, having sensing ability (ΔR/Rair%) for 20 ppm of toluene around 197%, 205%, and 217%, respectively. These results demonstrate how well the nanocomposite structures work to address MoS2's low gas sensing response and enhance overall sensing performance. The findings suggest that MoS2-based nanocomposites could be useful for sensing toluene gas.

Surfactant-like Additives Assisted the Lateral Growth of Pentacene Films.

Lateral growth of thin films is crucial for organic electronic devices, such as field-effect transistors. Here, we report a strategy to improve the lateral growth of pentacene films using rubrene as a surfactant-like additive. Atomic force microscopy (AFM) images confirm the enhanced lateral growth with the presence of rubrene, resulting in smooth and enlarged molecule domains in the films in comparison to those without rubrene. Molecular dynamics simulations are conducted to explore the interlayer diffusion of pentacene molecules during the growth. With the rubrene molecules as surfactant-like additives, mean square displacement (MSD) analysis shows that the pentacene molecules have a descending diffusion coefficient of 2.0 × 10-5 cm2 s-1, which is greater than the ascending diffusion coefficient of 1.6 × 10-5 cm2 s-1. The more descending molecules lead to an enhanced lateral growth of pentacene films, which is in good agreement with the experiments. As a result, the pentacene films grown with rubrene exhibit a rapid increase in carrier mobility over thickness due to the well-connected domains resulting from enhanced lateral growth. This finding will provide a new strategy to modulate the morphology of organic films for high-performance devices.

Improving the quality and properties of GaInSb crystal with Al doping

GaInSb crystal is a promising substrate material that can be used to prepare various high-performance devices. Ga0.86In0.14Sb and Al-doped Ga0.86In0.14Sb (Ga0.86In0.14Sb:Al) crystals were grown with the vertical Bridgman method (VB). The doping concentration of aluminum (Al) is 0.005–0.015 molar ratio. The effect of Al doping on the structure and properties of Ga0.86In0.14Sb crystal was studied. The results indicated that Al doping significantly reduced the segregation of indium (In) component in the crystal, with the radial segregation reaching a minimum of 0.051 mol% mm−1 and the axial segregation reaching a minimum of 0.067 mol% mm−1. The doping of Al also improved the crystal quality (lattice structure integrity) of Ga0.86In0.14Sb. The passivation and compensation of Al on the intrinsic defects of Ga0.86In0.14Sb crystal significantly inhibited the generation of dislocation, of which density decreased to 2.461 × 103 cm−2. The doping of Al as the equivalent electron element of gallium (Ga) and In not only made the carrier concentration increase to 1.848 × 1018 cm−3 but also made the carrier mobility increase to 1.982 × 103 cm2/(V·s), resulting in the resistivity decreasing to 1.261 × 10−3 Ω·cm.

Single-Crystal-Assisted In Situ Phase Reconstruction Enables Efficient and Stable 2D/3D Perovskite Solar Cells.

Perovskite solar cells (PSCs) that incorporate both two-dimensional (2D) and three-dimensional (3D) phases possess the potential to combine the high stability of 2D PSCs with the superior efficiency of 3D PSCs. Here, we demonstrated in situ phase reconstruction of 2D/3D perovskites using a 2D perovskite single-crystal-assisted method. A gradient phase distribution of 2D RP perovskites was formed after spin-coating a solution of the 2D Ruddlesden-Popper (RP) perovskite single crystal, (DFP)2PbI4, onto the 3D perovskite surface, followed by thermal annealing. The resulting film exhibits much reduced trap density, increased carrier mobility, and superior water resistance. As a result, the optimized 2D/3D PSCs achieved a champion efficiency of 24.87% with a high open-circuit voltage (VOC) of 1.185 V. This performance surpasses the control 3D perovskite device, which achieved an efficiency of 22.43% and a VOC of 1.129 V. Importantly, the unencapsulated device demonstrates significantly enhanced operational stability, preserving over 97% of its original efficiency after continuous light irradiation for 1500 h. Moreover, the extrapolated T80 lifetimes surpass 5700 h. These findings pave the way for rational regulation of the gradient phase distribution at the interface between 2D and 3D perovskites by employing 2D RP perovskite crystals to achieve stable and efficient PSCs.

Sensing and slow light applications of graphene plasmonic terahertz structure

In this work, Ansys FDTD is used to design and simulate a terahertz metamaterial structure based on periodic continuous pattern graphene monolayer, and the high-quality PIT phenomena are obtained by continuously adjusting structural parameters. To validate the designed structure, the simulated transmission curve (reflection curve) obtained is compared with the theoretical transmission curve (reflection curve) derived from coupled-mode theory. It is observed that these two results exhibit a remarkably high degree of overlap. The resonant frequency and Fermi energy reveals a perfect linear correlation between them with the resonant frequency increasing proportionally with Fermi energy increasing. Dynamic tuning of PIT can be realized by adjusting the Fermi energy of graphene. For a more in-depth study of its sensing characteristics, the structure is placed in different environments. As the refractive index of the detection medium increases, the resonant frequency gradually decreases, demonstrating a redshift phenomenon. By manipulating the resonant frequency of the PIT sensor, the selective detection of specific target can berealized. After analyzing the sensitivity and FOM values of the structure, it is found that the maximum sensitivity is 1.457 THz/RIU. At a resonant frequency of 6.8174 THz, FOM reaches 30.5652. In summary, the sensor structure designed in this work has dual frequency sensing characteristics and can be used for dual frequency detection. Moreover, compared with other sensor structures, it demonstrates superior sensing performance. Additionally, in studying the slow light effect of the structure, it is found that as the Fermi energy increases, the group index and phase shift at the transparency window continue to increase. At the Fermi energy of 1.2 eV, the group index reaches a high value of 584. This is because in the PIT phenomenon, transparent peaks are formed due to multimodal coupling. This coupling will significantly improve the dispersion characteristics near the transparent peak, resulting in a large group index near the transparent peak. Furthermore, with the increase of carrier mobility, the group index and phase shift of the structure also gradually increase. At a carrier mobility of 0.75 m²/(V·s), the group refractive index is 456, and reaches 1010 at 2.0 m²/(V·s). In this study, the slow-light performance of graphene structure can be optimized through jointly adjusting the Fermi energy and carrier mobility. This research provides theoretical support and methods for designing advanced graphene-based sensors and devices for slow-light applications.

Enhanced photoelectric performance in Cu–Bi double halide perovskite single crystals

The low-dimensional structures of Bi-based perovskites severely restrict their optoelectronic performances. Here, a Cu–Bi double perovskite single crystal exhibits enhanced optical absorption, increased carrier mobility, and inhibition of defect recombination compared to Bi-only perovskite.

A facile and scalable fabrication method of scrolled graphene/boron nitride-based van der Waals superlattice heterostructure materials for highly stable supercapacitor electrode application.

Due to the increasing demand for the development of efficient renewable energy supply systems to reduce the mismatch between energy demand and utilization, supercapacitors have attracted increasing attention in the energy industry. However, the development of energy storage electrode materials to be applied at the industrial level is still challenging due to the unsatisfactory durability and scalable production issues. This study suggested a facile and scalable one-pot fabrication method of using graphene/hexagonal boron nitride (G/BN)-based one-dimensional (1D) van der Waals superlattice heterostructures (vdWSLs) as highly stable electrode materials to enhance the energy storage performance by improving the mesopore volume content, specific surface area, electrical properties, and interfacial interaction between the stacked G/BN layers. The G/BN-based vdWSLs were fabricated by a simple scrolling process through the electromagnetic interaction between the attached magnetic iron oxide nanoparticles (Fe3O4 NPs) on the surface of a G/BN vdW heterostructure (vdWH) and the applied magnetic field. The investigation results demonstrate that the changed morphology of the fabricated G/Fe/BN(NS) strongly affects the fine pore distribution, electrochemical performance, and electrical properties. Consequently, as a synergistic effect of an increased mesopore volume content, specific surface area, and C-B-N heterojunction interfacial area, the fabricated G/Fe/BN(NS) electrode showed a 100% enhancement of specific capacitance (207 F g-1 at 0.5 A g-1) and almost 7 times enhancement of electrical conductivity (800 S cm-1) with a nearly 2.3 times increase of carrier mobility (716 cm2 V-1 s-1) compared to that of the G/Fe/BN electrode. Furthermore, it exhibited outstanding long-term cycling stability with almost 119% capacitance retention even after 100 000 charge-discharge cycles. These results suggest that G/Fe/BN(NS) has tremendous potential as an electrode to fabricate high-performance supercapacitors with excellent cycling stability.

Reversible Transition of Semiconducting PtSe2 and Metallic PtTe2 for Scalable All-2D Edge-Contacted FETs.

Two-dimensional (2D) transition metal dichalcogenide (TMD) layers are highly promising as field-effect transistor (FET) channels in the atomic-scale limit. However, accomplishing this superiority in scaled-up FETs remains challenging due to their van der Waals (vdW) bonding nature with respect to conventional metal electrodes. Herein, we report a scalable approach to fabricate centimeter-scale all-2D FET arrays of platinum diselenide (PtSe2) with in-plane platinum ditelluride (PtTe2) edge contacts, mitigating the aforementioned challenges. We realized a reversible transition between semiconducting PtSe2 and metallic PtTe2 via a low-temperature anion exchange reaction compatible with the back-end-of-line (BEOL) processes. All-2D PtSe2 FETs seamlessly edge-contacted with transited metallic PtTe2 exhibited significant performance improvements compared to those with surface-contacted gold electrodes, e.g., an increase of carrier mobility and on/off ratio by over an order of magnitude, achieving a maximum hole mobility of ∼50.30 cm2 V-1 s-1 at room temperature. This study opens up new opportunities toward atomically thin 2D-TMD-based circuitries with extraordinary functionalities.

Synergetic mixed ionic liquid strategy for comprehensive defect passivation and increased carrier mobility in high-performance green perovskite light-emitting diodes

Metal halide perovskites have recently garnered significant attention owing to their potential in light-emitting diode applications. The performance of perovskite light-emitting diodes (PeLEDs) can be significantly influenced by mitigating the halide vacancy-related defects and optimizing the morphology of the perovskite layer. Achieving defect passivation in perovskites often involves the incorporation of electrically insulating long-chain ligands, which can result in the transformation of the three-dimensional perovskite structure to lower-dimensional structures. This enhances its optoelectronic properties, but reduces the interparticle charge transport, thus limiting the performance of the PeLEDs. This study demonstrates a novel approach for passivating defects by utilizing mixed ionic liquid (IL) additives, namely 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) and 1-benzyl-3-methylimidazolium tetrafluoroborate (BZIMBF4). The BMIMBF4 enhances carrier mobility, whereas BZIMBF4 enhances the film morphology and improves defect passivation within the perovskite active layer. Consequently, the mixed IL strategy enables improved control over the crystal growth kinetics, alteration of crystallographic orientation, superior defect passivation, and adjustment of the energy band levels. Additionally, this IL-based approach maintains the three-dimensional structure of the perovskite, thus preserving good charge transport properties compared to organic ligands. These combined effects result in high-performance green PeLEDs with a maximum external quantum efficiency of 20.03% and a brightness of 57599.36 cd/m2.

Prominent texturing and enhanced thermoelectric performance of misfit layered (PbS)1.18(TiS2)2 via an exfoliation-restacking approach

Micro-texturing engineering has been taken to manipulate the thermoelectric performance of (PbS)1.18(TiS2)2 via an exfoliation-restacking approach coupled with spark plasma sintering. The resultant polycrystalline material showed remarkably promoted (00l) texturing together with a noticeable reduction in grain size, leading to prominently prior transport properties along the in-plane direction. Particularly, the electrical conductivity was much improved due to the increased carrier mobility without affecting carrier concentration and DOS effective mass, which gave rise to a maintained Seebeck coefficient and consequently a high power factor of 8.8–11.4 μW·cm−1·K−2 in the range of 323 – 773 K. Despite the slightly increased thermal conductivity due to electronic component and the limited suppression of phonon transport, a record-high ZT value of 0.52 has been achieved with an increase by ∼20% compared to that of the pristine one, demonstrating the significant effectiveness of exfoliation-restacking on boosting the thermoelectric performance for misfit layered materials.

Electrical transport properties of ZrS2 under high pressure

The investigation of the electrical transport properties of ZrS2 is conducted up to 30.7 GPa using first-principles calculation and electrical experimental methods. The electrical parameters of ZrS2 are investigated under high pressure conditions using the thin film integrated microcircuit technology on a diamond anvil cell. The structural phase transitions occur at approximately 2.0 GPa and 6.0 GPa, as evidenced by changes in the energy band structure and discontinuities in electrical parameters. At around 12.3 GPa, the pressure-induced metallization is observed by temperature-induced resistivity and the closing of the band gap. The sudden decrease in resistivity can be attributed to the combined contribution of an increase in carrier concentration and mobility. Similarly, the abrupt decrease in Hall coefficient is attributed to the increase in carrier concentration.

Twinning behavior and thermoelectric performance of Cu2SnS3

With the perfect and orderly atomic arrangement, nanotwins could effectively scatter mid- and low-frequency phonons while minimizing the scattering for carriers, beneficial for enhancing the thermoelectric properties of materials. To unlock these features, we explored the twin structural characteristics in Cu2SnS3 and found that nanotwins formed along [100] direction on the glide-set plane, and further delved into the mechanism of twin formation and found that twinning possessed a lower nucleation barrier than the slipping. In addition, we reduced the unstable stacking fault energy in the stacking stage and amplified the probability of twin formation by introducing Se atoms at the S sites. In spite of more nanotwins, a slight increase in carrier mobility was realized, leading to a maximum power factor of 5.5 μW cm−1 K−2 at 773 K for the Cu2SnS2Se material. Meanwhile, the lattice thermal conductivity across the entire temperature range was effectively reduced due to the introduction of nanotwins and SeS points defects, which is approximately 0.46 W m−1 K−1 at 773 K for Cu2SnS2Se. Further optimization of the power factor was realized by utilizing a high-efficient doping strategy via introducing Sn vacancies. The carrier concentration became significantly augmented while minimizing ionized impurities scattering, giving rise to an exceptionally high power factor of 8.2 μW cm−1 K−2 and a highly-ranked thermoelectric figure of merit of 0.98 at 773 K for Cu2Sn0.99S2Se. Our work demonstrates an intriguing route towards the high thermoelectric performance of Cu2SnS3 through the introduction of nanotwins as well as high-efficient doping techniques.

Highly Bright and Stable Lead-Free Double Perovskite White Light-Emitting Diodes.

Lead-free double perovskites (DPs) are emerging highly stable emitters with efficient broadband self-trapped exciton (STE) photoluminescence (PL), but their low electroluminescent (EL) efficiency is a critical shortcoming. This work promotes the external quantum efficiency (EQE) and luminance of DP-based white light-emitting diode (wLED) with a normal device structure to 0.76% and 2793cd m-2 via two modifications: This work prevents the formation of adverse metallic silver, spatially confined STE, and lowers local site symmetry in Cs2 Na0.4 Ag0.6 In0.97 Bi0.03 Cl6 DP by terbium doping; and this work develops a guest-host strategy to improve film morphology, reduce defect density, and increase carrier mobility. These alterations cause substantial increase in STE radiative recombination and charge injection efficiency of perovskite layer. Finally, pure white EL with ideal color coordinates of (0.328, 0.329) and a record-breaking optoelectronic performance is achieved by introducing additional green carbon dots in LED to fill the deficient green component.

Introduction of Metal Coordination Bonds into Conjugated Polymers to Increase Carrier Mobility and Stretchability

Introduction of Metal Coordination Bonds into Conjugated Polymers to Increase Carrier Mobility and Stretchability

The electron–phonon scattering and charge transport of the two-dimensional (2D) polar h-BX(X = P, As, Sb) monolayers

In this paper, the electron–phonon scattering and phonon-limited transport properties of the two-dimensional polar h-BX(X = P, As, Sb) have been studied through first-principles calculations in combination with Boltzmann transport theory. The electron–phonon scattering in these three systems is systematically assessed. Remarkably, intravalley scattering and intervalley scattering are separately investigated, of which the contribution to total scattering is found to be relatively comparable. The carrier mobility is determined over a broad range of carrier concentrations. The results indicate that h-BX (BP, BAs, BSb) simultaneously possess ultrahigh electron mobilities (4097 cm2 V−1 s−1, 4141 cm2 V−1 s−1, 12 215 cm2 V−1 s−1) and hole mobilities (7563 cm2 V−1 s−1, 7606 cm2 V−1 s−1, 22 282 cm2 V−1 s−1) at room temperature as compared to the most known two-dimensional (2D) materials. Additionally, it is discovered that compressive strain can induce a further increase in carrier mobility. The exceptional charge transport properties exhibited by these 2D semiconductors are attributed to the small effective masses in combination with the significant suppression of scattering due to high optical longitudinal optical- and transverse optical-phonon frequencies. This is the first time that we have provided a systematic interpretation of the reason for the exceptional charge transport properties exhibited by the 2D h-BX(X = P, As, Sb) semiconductors. Our finding can provide a theoretical perspective regarding the search for 2D materials with the high carrier mobility.

Numerical simulation and characterization of high-power gallium nitride based Junctionless Accumulation Mode Nanowire FET (GaN-JAM-NWFET) for small signal high frequency terahertz applications

This paper presents numerical simulation and characterization of high-power Gallium Nitride Junctionless Accumulation Mode Nanowire FET (GaN-JAM-NWFET) which has improved analog performance and is suitable for high-frequency applications. In GaN-JAM-NWFET, GaN and Aluminium Oxide (Al2O3) replace Silicon (Si) and Silicon Oxide (SiO2), respectively. Because of the larger bandgap and strong breakdown field, GaN based devices can handle higher voltages and powers with good carrier transport qualities, which permit a higher driving current than Si devices. Moreover, GaN-JAM-NWFET has a better performance than GaN based Junctionless (JL) NWFET due to the benefit of JAM structure over JL device, having increased carrier mobility in the lightly doped channel. These cumulative benefits of GaN with JAM manifest improvement in drain current, output conductance, subthreshold swing, transconductance, gate capacitance, cut-off frequency, Frequency Transconductance Product (FTP), Gain Frequency Product (GFP), Gain Transconductance Frequency Product (GTFP), intrinsic gain, Unilateral Power Gain (UPG) and Maximum Transducer Power Gain (MTPG) in proposed GaN-JAM-NWFET among GaN-JL-NWFET, Si based JAM NWFET, and Si-JL NWFET devices. The S-parameters such as transmission coefficients (S12 & S21) and reflection coefficients (S11 & S22) also confirm the proposed GaN-JAM-NWFET has better small signal performance than other devices.