Variable Band Gap Research Articles

Nitrogen-doped carbon quantum dot-decorated In2O3 synaptic transistors for neuromorphic computing

Nitrogen-doped carbon quantum dots (N-CQDs) are promising materials for electronic devices due to their variable bandgap and structural stability. Here, we integrate N-CQDs into In2O3 synaptic transistors with electrolyte gating, resulting in a hybrid structure. The surface functional groups and defects of N-CQDs empower the charge trapping mechanism, permitting controlled conduction and charge regulation, which are crucial for emulating linear and symmetric artificial synaptic devices. Devices incorporating N-CQDs demonstrate enhanced stability and memory characteristics, low energy consumption, consistent retention, and a significant hysteresis window across multiple voltage cycles. Finally, the study emulates biological synapses and cognitive functions, achieving an energy consumption of 10 fJ per synaptic event and a pattern recognition accuracy of 91.2% on the MNIST dataset in hardware neural networks. This work demonstrates the potential of well-manipulating charge trapping in N-CQDs to develop high-performance, nonvolatile synaptic devices.

Nonlinear dynamics of continuous steady-state tunable mechanical metamaterials based on planetary gears

Mechanical metamaterials with tunable mechanical properties have received extensive attention. In this work, a continuous steady-state metamaterial with tunable mechanical based on planetary gear cells is designed. Firstly, the excellent tunable properties of metamaterials are studied, which shows the designed metamaterials has a wide range of programmable stiffness and a significantly tunning band gap. The configuration relationship between tunability and structural parameters is analyzed. Then, a rigid-flexible coupling nonlinear dynamic model of planetary gear metamaterials is established and the dynamic characteristics of planetary gear metamaterials in the process of dynamic tunning are explored by numerical simulation. Moreover, the distribution characteristics of the system vibration response with the coupling parameter plane are disclosed, and the influence of the system dynamic parameters on its bifurcation characteristics and stability under coupling excitation is explored. Furthermore, an improved non-iterative cell mapping method is used to analyze the dependence of the vibration response of the system on the initial conditions. This work shows that the planetary gear metamaterials have a wide range of stiffness tunability and significantly variable band gap interval. Under the influences of internal and external excitations, the system exhibits various dynamic characteristics. The dynamic characteristics of flexible construction are mainly affected by structural parameters, and the dynamic characteristics of rigid construction are affected by multiple sets of coupling parameters and initial conditions.

Tuning of bandgap for warm white light emissions in indium-doped cesium metal halide perovskites by solvothermal method

Cesium-based perovskites, particularly Cs3Bi2Br9, doped with indium, have emerged as promising materials for energy-efficient lighting, notably in white light-emitting diodes (WLEDs). This study aimed to address environmental concerns associated with lighting technology by employing solvothermal synthesis to fabricate these materials. Comprehensive characterization techniques, including X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence spectroscopy (PL), were applied to assess their properties. XRD analysis confirmed the formation of Cs3Bi2Br9 with a trigonal crystal structure and indium doping induced significant changes in the material’s color and crystal lattice. TEM imaging, even after six months, revealed the presence of stable nanocrystals, indicating the material’s durability in practical applications. UV–Vis absorption and photoluminescence spectroscopy showed variable bandgaps and efficient photon emission. Notably, as the indium doping concentration increased, the emitted light shifted from blue to bluish-white, making these materials highly suitable for the synthesis of WLEDs. This research offers a promising prospect to address environmental issues associated with lighting technology while advancing energy-efficient illumination solutions.

Development of MRE-based metamaterial with adjustable frequency bandgap for seismic vibration isolation

A seismic isolation system is an engineering method to prevent structures from the undesirable vibrations of earthquake. It involves using isolators, dampers, and bearings to decouple the superstructure from the ground during seismic waves by reducing the forces and accelerations transferred to the structure. The goal of this research is to investigate the tunable MRE-based metamaterial foundation for seismic vibration isolation. Metamaterials with adaptive and variable frequency band gaps are preferred because earthquakes have a wide range of frequencies. By varying the magnetic field intensity, a magnetorheological elastomer (MRE)-based metamaterial foundation can modify its Young's modulus and stiffness. The frequency band gap or frequency range of the MRE-based metamaterial foundation can be shifted by tunable material properties. Under the effect of a magnetic field, a uniaxial compression test was conducted to evaluate the Young's modulus of three types of MRE samples. Following the compression test, a series of numerical simulations in ABAQUS were carried out using a two-story framed building with RC and MRE-based metamaterial foundation. Three earthquake excitations are used: Bishop, Oroville, and Imperial Valley. The experimental results suggest that the magnetic field influences the MRE's Young's modulus. Similarly, numerical simulation studies indicate that the magnetic field influences the frequency band gap of the MRE-based metamaterial foundation. The FRF results of conventional RC foundation and MRE-based foundation are compared, highlighting the efficiency of MRE-based foundation in vibration control by reducing the seismic vibration of a structure by 68.5 %.

Fluorescent Graphitic Carbon Nitride (g-C3N4)-Embedded Hyaluronic Acid Microgel Composites for Bioimaging and Cancer-Cell Targetability as Viable Theragnostic.

Fluorescent graphitic carbon nitride (g-C3N4) doped with various heteroatoms, such as B, P, and S, named Bg-C3N4, Pg-C3N4, and Sg-C3N4, were synthesized with variable band-gap values as diagnostic materials. Furthermore, they were embedded within hyaluronic acid (HA) microgels as g-C3N4@HA microgel composites. The g-C3N4@HA microgels had a 0.5-20 μm size range that is suitable for intravenous administration. Bare g-C3N4 showed excellent fluorescence ability with 360 nm excitation wavelength and 410-460 emission wavelengths for possible cell imaging application of g-C3N4@HA microgel composites as diagnostic agents. The g-C3N4@HA-based microgels were non-hemolytic, and no clotting effects on blood cells or cell toxicity on fibroblasts were observed at 1000 μg/mL concentration. In addition, approximately 70% cell viability for SKMEL-30 melanoma cells was seen with Sg-C3N4 and its HA microgel composites. The prepared g-C3N4@HA and Sg-C3N4@HA microgels were used in cell imaging because of their excellent penetration capability for healthy fibroblasts. Furthermore, g-C3N4-based materials did not interact with malignant cells, but their HA microgel composites had significant penetration capability linked to the binding function of HA with the cancerous cells. Flow cytometry analysis revealed that g-C3N4 and g-C3N4@HA microgel composites did not interfere with the viability of healthy fibroblast cells and provided fluorescence imaging without any staining while significantly decreasing the viability of cancerous cells. Overall, heteroatom-doped g-C3N4@HA microgel composites, especially Sg-C3N4@HA microgels, can be safely used as multifunctional theragnostic agents for both diagnostic as well as target and treatment purposes in cancer therapy because of their fluorescent nature.

Graphene nanoribbon derived from multi-walled carbon nanotube: An efficient viral gene hosting and biosensing molecular platform for the electroanalysis of HIV-1 gene

Graphene nanoribbon (GNR) is a carbon nanomaterial with strikingly distinct characteristics compared to graphene. GNRs possess high aspect ratio, variable band gap, high surface area and high density of reactive edge states which make it an emerging flat molecular platform alternative to graphene. GNR is not much explored in sensing applications compared to graphene. Here, for the first time, we are reporting the application of GNRs, derived from multiwalled carbon nanotube (MWCNT), as an efficient flat molecular platform for hosting and biosensing of Human immune deficiency virus-1 (HIV-1) gene. For the construction of HIV-1 sensor, GNRs were synthesized by unzipping of MWCNTs and deposited onto glassy carbon electrode (GCE) followed by the immobilization of HIV-1 probe (ssDNA) onto the resulting GCE/GNR platform to obtain GCE/GNR/ssDNA sensor. Subsequently, the sensor was employed in the analysis of target gene (cDNA) by measuring the voltammetric response generated from hybridization between ssDNA and cDNA. Differential pulse voltammetry (DPV) responses recorded at different target gene concentrations displayed perfect linear correlation (R2 = 0.991). The sensor exhibited low detection limit (2.3 aM), low quantification limit (7.67 aM) and high sensitivity (5.5 μA aM−1 cm−2) which is possibly due to synergic effects of GNRs. Sensor exhibited acceptable stability, repeatability and displayed good selectivity when tested with mismatched target DNA sequences. Further, sensor’s diagnostic applicability was verified by spiking target gene in human blood sample which showed high recovery (4 %) indicating its practical utility in the electroanalysis of HIV-1 gene in human blood samples.

A comprehensive investigation of the Sr3AsX3 (X = F/Cl/Br) inorganic cubic perovskites' strain-induced structural, electronic, optical, and mechanical properties with solar cell applications.

In comparison to the lead halide perovskites, nowadays, lead-free halide perovskites have demonstrated a number of benefits, including efficient optical absorption, increased stability, variable bandgap, excellent mobility of carriers, non-toxicity, abundant raw ingredients, and low manufacturing cost. The use of the Perdew-Burke-Ernzerhof (PBE) and Heyd-Scuseria-Ernzerhof (HSE) hybrid functional inside the quantum espresso software allowed for a thorough examination of these materials, potentially leading to improvements in the development of ecologically acceptable and economically sustainable perovskite-based products. This work has extensively examined the effects of compressive and tensile strain on the structural, optical, and electronic characteristics of the inorganic cubic perovskite Sr3AsX3 (X = F, Cl, Br) with varying X anion using first-principles density-functional theory (FP-DFT). At the Γ point, the unstrained Sr3AsF3, Sr3AsCl3, and Sr3AsBr3 compounds have a direct bandgap of 1.68/2.50 eV, 1.65/2.47 eV, and 1.522/2.30 eV, respectively, from the PBE/HSE methods. A drop in bandgap values occurs when the X-anion switches from F to Cl to Br. Furthermore, the bandgaps of the three proposed structures show a minor increase in response to tensile strain and a decreasing prevalence in response to compressive strain. The optical properties, which include dielectric functions, absorption coefficient, and electron loss function, are consistent with the band characteristics of these components, all of which point to a significant capability for absorption in the visible region. The dielectric constants of Sr3AsF3, Sr3AsCl3, and Sr3AsBr3 are discovered to have peaks that, with compressive strain, redshift (move towards lower photon energy) and, under tensile strain, blueshift (move towards upper photon energy). In comparison to the compounds Sr3AsF3 and Sr3AsCl3, the parameters indicate that the material Sr3AsBr3 is more optically advantageous. The SCAPS-1D simulator was used to methodically examine the photovoltaic (PV) performance of novel cell topologies that included SnS2 as an electron transport layer (ETL) and Sr3AsF3, Sr3AsCl3, and Sr3AsBr3 as absorbers and primarily 19.76, 19.89, and 20.89% PCE was achieved, respectively.

The Developing Field of Hybrid Perovskite Semiconductor Nanomaterials: A Survey of Recent Advances in their Production and Usage for Optoelectronic Applications.

Due to its distinctive characteristics, including high absorption coefficients, lengthy carrier diffusion lengths, and variable bandgap energies, hybrid perovskite semiconductor nanomaterials have become a potential class of materials for a variety of optoelectronic applications. In this article, we present a thorough analysis of current advancements in the production and application of hybrid perovskite semiconductor nanomaterials. We go over the different ways to create these materials, such as hybrid techniques, vapor-phase deposition, and solution-phase synthesis. We also emphasize the difficulties in synthesising them as well as the solutions being sought. The use of hybrid perovskite semiconductor nanomaterials for optoelectronic devices including photovoltaic, light-emitting diodes, and photo detectors has made some significant strides, which we also review. Lastly, we go over the open questions and potential research routes in this quickly developing area. This review highlights the revolutionary potential of hybrid perovskite semiconductor nanomaterials and offers a thorough overview of the state-of-the-art in this field.

A Novel 3D-Printed Negative-Stiffness Lattice Structure with Internal Resonance Characteristics and Tunable Bandgap Properties.

The bandgap tuning potential offered by negative-stiffness lattice structures, characterized by their unique mechanical properties, represents a promising and burgeoning field. The potential of large deformations in lattice structures to transition between stable configurations is explored in this study. This transformation offers a novel method for modifying the frequency range of elastic wave attenuation, simultaneously absorbing energy and effectively generating diverse bandgap ranges. In this paper, an enhanced lattice structure is introduced, building upon the foundation of the normal negative-stiffness lattice structures. The research examined the behavior of the suggested negative-stiffness lattice structures when subjected to uniaxial compression. This included analyzing the dispersion spectra and bandgaps across different states of deformation. It also delved into the effects of geometric parameter changes on bandgap properties. Furthermore, the findings highlight that the normal negative-stiffness lattice structure demonstrates restricted capabilities in attenuating vibrations. In contrast, notable performance improvements are displayed by the improved negative-stiffness lattice structure, featuring distinct energy band structures and variable bandgap ranges in response to differing deformation states. This highlights the feasibility of bandgap tuning through the deformation of negatively stiffened structures. Finally, the overall metamaterial structure is simulated using a unit cell finite element dynamic model, and its vibration transmission properties and frequency response patterns are analyzed. A fresh perspective on the research and design of negative-stiffness lattice structures, particularly focusing on their bandgap tuning capabilities, is offered in this study.

Progress in the Synthesis Process and Electrocatalytic Application of MXene Materials.

With their rich surface chemistry, high electrical conductivity, variable bandgap, and thermal stability, 2D materials have been developed for effective electrochemical energy conversion systems over the past decade. Due to the diversity brought about by the use of transition metals and C/N pairings, the 2D material MXene has found excellent applications in many fields. Among the various applications, many breakthroughs have been made in electrocatalytic applications. Nevertheless, related studies on topics such as the factors affecting the material properties and safer and greener preparation methods have not been reported in detail. Therefore, in this paper, we review the relevant preparation methods of MXene and the safer, more environmentally friendly preparation techniques in detail, and summarize the progress of research on MXene-based materials as highly efficient electrocatalysts in the electrocatalytic field of hydrogen precipitation reaction, nitrogen reduction reaction, oxygen precipitation reaction, oxygen reduction reaction, and carbon dioxide reduction reaction. We also discuss the technology related to MXene materials for hydrogen storage. The main challenges and opportunities for MXene-based materials, which constitute a platform for next-generation electrocatalysis in basic research and practical applications, are highlighted. This paper aims to promote the further development of MXenes and related materials for electrocatalytic applications.

Defect control and optical performance of yttrium orthovanadate nanocrystals via a facile pH-sensitive synthesis

Nanocrystalline YVO4 powders have been synthesized via a facile co-precipitation method, which has been investigated over the wide pH range from 4 to 13. XRD patterns indicated that the phase structure purity of the precipitation is influenced by the pH value. The reaction mechanism of YVO4 crystal was suggested to illustrate the development stages beginning with precipitates to form impure amorphous phase structures such as amorphous yttrium polyvanadate and hydrous Y(OH)3. SEM and TEM techniques were performed to observe the changes of the morphology and size by adjusting the pH conditions after YVO4 nanocrystals were sintered under ambient conditions at 600 °C for 2 h. Luminescence properties showed that the self-activated emission of YVO4 matrix material shows an obvious peak at 486 nm in the 400–650 nm wavelength range, attributing to the charge transfer in the vanadate groups. With decreasing the pH value, the diffuse reflectance spectra of YVO4 nanocrystals demonstrated that the energy gap Eg showed a red-shift trend mainly ascribed to the oxygen vacancies. Moreover, the luminescence emission intensity of YVO4 nanocrystals increases obviously after sintering treatment, which can be explained by the sintering-induced grain growth and improved surface band bending due to the dehydration or the removal of carbonate species. The findings of this study could provide new insights into the understanding of the reaction mechanism of YVO4 crystal with variable optical band gap and offer an opportunity for realizing tunable optical performance by defect structure regulation for laser and optoelectronics applications.

Band-gap engineering of zirconia by nitrogen doping in reactive HiPIMS: a step forward in developing innovative technologies for photocatalysts synthesis.

In the global context of climate change and carbon neutrality, this work proposes a strategy to improve the light absorption of photocatalytic water-splitting materials into the visible spectrum by anion doping. In this framework, reactive high power impulse magnetron sputtering (HiPIMS) of a pure Zr target in Ar/N2/O2 gas mixture was used for the deposition of crystalline zirconium oxynitride (ZrO2-xNx) thin films with variable nitrogen doping concentration and energy band-gap. The nitrogen content into these films was controlled by the discharge pulsing frequency, which controls the target surface poisoning and peak discharge current. The role of the nitrogen doping on the optical, structural, and photocatalytic properties of ZrO2-xNx films was investigated. UV-Vis-NIR spectroscopy was employed to investigate the optical properties and to assess the energy band-gap. Surface chemical analysis was performed using X-ray photoelectron spectroscopy, while structural analysis was carried out by X-ray diffraction. The increase in the pulse repetition frequency determined a build-up in the nitrogen content of the deposited ZrO2-xNx thin films from ∼10 to ∼25at.%. This leads to a narrowing of the optical band-gap energy from 3.43 to 2.20eV and endorses efficient absorption of visible light. Owing to its narrow bandgap, ZrO2-xNx thin films obtained by reactive HiPIMS can be used as visible light-driven photocatalyst. For the selected processing conditions (pulsing configuration and gas composition), it was found that reactive HiPIMS can suppress the hysteresis effect for a wide range of frequencies, leading to a stable deposition process with a smooth transition from compound to metal-sputtering mode.

Solvent effects on the drop cast films of few layers of MoS2 primed by facile exfoliation to realize optical and structural properties

MoS2, a two-dimensional (2D) layered material with variable bandgap and high stability, can be employed in optical and electronic applications due to its outstanding structural, electrical, and optical properties. The fabrication of MoS2 devices in a facile way is highly inevitable to minimize the time consumption and the cost due to its far-reaching and ceaseless applications. On behalf of their various applications, we have employed sonication-assisted liquid phase exfoliation of MoS2 followed by drop casting the sample in a glass plate for further characterization. MoS2 nanosheets were fabricated by exfoliating bulk MoS2 powder in different solvents with varying surface tension such as Ethanol, Ethylene Glycol (EG), Polyvinyl Pyrrolidone (PVP), Dimethylformamide (DMF), and Dimethyl Sulfoxide (DMSO). The structural and optical properties of the sample were analyzed using XRD, AFM, UV spectroscopy, photoluminescence (Pl) and Raman spectroscopy. The formation of 2D MoS2 film with (0 0 2) planes were identified and the thickness of the exfoliated nanosheets was confirmed to be in the nano regime. The optical properties of MoS2 revealed the existence of the spin–orbit coupling and the exciton-plasmon (plexitonic) coupling induced Rabi splitting in the Pl spectra, which increased with a reduction in layer number, and a negative correlation between Pl intensity and Rabi splitting is established. The variation in layer number of MoS2 on different solvents has been studied using the difference in Raman shift between E12g and A1g modes.

A Wrinkling and Etching-Assisted Regrowth Strategy for Large-Area Bilayer Graphene Preparation on Cu.

Bilayer graphene is a contender of interest for functional electronic applications because of its variable band gap due to interlayer interactions. Graphene growth on Cu is self-limiting, thus despite the fact that chemical vapor deposition (CVD) has made substantial strides in the production of monolayer and single-crystal graphene on Cu substrates, the direct synthesizing of high-quality, large-area bilayer graphene remains an enormous challenge. In order to tackle this issue, we present a simple technique using typical CVD graphene growth followed by a repetitive wrinkling-etching-regrowth procedure. The key element of our approach is the rapid cooling process that causes high-density wrinkles to form in the monolayer area rather than the bilayer area. Next, wrinkled sites are selectively etched with hydrogen, exposing a significant portion of the active Cu surface, and leaving the remaining bilayer areas, which enhance the nucleation and growth of the second graphene layer. A fully covered graphene with 78 ± 2.8% bilayer coverage and a bilayer transmittance of 95.6% at room temperature can be achieved by modifying the process settings. Bilayer graphene samples are examined using optical microscopy (OM), scanning electron microscopy (SEM), Raman spectroscopy, and an atomic force microscope (AFM) during this process. The outcomes of our research are beneficial in clarifying the growth processes and future commercial applications of bilayer graphene.

Graphite–hexagonal diamond hybrid with diverse properties

The recently discovered graphite–diamond hybrid materials (Gradia) with mixed sp2- and sp3-hybridizations have opened up a new direction in carbon allotropes research. Herein, we reported Gradia-HZ, constituted by interfaced graphite and hexagonal diamond parts in the unit cell, which demonstrates distinct electronic and mechanical properties. With the modulation of graphite width, Gradia-HZ exhibits unexpected topological nodal-line semimetal, semiconductor, and normal metal integrating with a distinctive Quasi-1D electronic transport capability based on first-principles calculations. More interestingly, pressure-induced graphite phase transformation might be an implementable and effective method to regulate the structure and physical properties of Gradia-HZ. The discovery of rich and peculiar physical properties in Gradia-HZ, e.g., high-conductivity metals, semiconductors with variable bandgap, and topological semimetals, will arouse great research interest to graphite–diamond hybrid materials, to promote their development and application in advanced devices.

Modeling Lattice Matched Dilute Nitride Triple and Quadruple Junction Solar Cells on Virtual SiGe Substrate

A lattice matched triple junction solar cell (TJSC) structure with a GaAs0.58 P0.42 top cell and bandgap tunable GaNxAs1-x-zPz middle and bottom cells on virtual SiGe substrate is proposed in this study. SiGe/Si substrate is preferred as it is a low-cost substrate and because it provides a lattice constant at which bandgap tunable dilute nitride materials that are appropriate for highly efficient multijunction solar cells can be obtained. By changing the nitrogen content in GaNxAs1-x-zPz, the bandgap of the middle and bottom subcells is adjusted to the optimum values. The bandgap of the top cell is constant at 1.95 eV. Three models with different values of surface recombination velocities and Shockley–Read–Hall recombination lifetimes are applied to the presented TJSC structure. Peak efficiencies of 48.9%, 40.6% and 33.7% are achieved at EG2 = 1.45 eV and EG3 = 1.04 eV for Model 1, EG2 = 1.45 eV and EG3 = 1.15 eV for Model 2, and EG2 = 1.5 eV and EG3 = 1.17 eV for Model 3, respectively. A fourth bandgap adjustable GaNxAs1-x-zPz junction is inserted into the system and a significant improvement is obtained under high sun concentration for Models 1 and 2. The presented original results are very promising because the variable bandgaps provide very efficient absorption of incoming spectrum.

Hydrogen evolution properties: Cr doping and V co-doping effect of ZnS nanoparticles

In this study, the effects of Cr doping and V co-doping on the hydrogen (H2) evolution properties of ZnS nanoparticles (NPs) were evaluated. An economical and facile hydrothermal method was used to synthesize ZnS, Zn0.99Cr0.01S, Zn0.98V0.01Cr0.01S, and Zn0.97V0.02Cr0.01S NPs. All the samples exhibited a cubic structure with effective Cr doping and V co-doping in the parent ZnS lattice. The variable bandgap of ZnS was engineered by Cr doping and V co-doping. Therefore, blue emission with a diminished fluorescence efficiency was achieved for the ZnS system by doping and co-doping. The Zn0.97V0.02Cr0.01S system showed the highest H2 evolution potential (12098 µmol h−1g−1) in 5 h under artificial solar illumination. Thus, V co-doping enriched the H2 production capacity of the ZnS:Cr system.

Shift current photovoltaic efficiency of 2D materials

Shift current photovoltaic devices are potential candidates for future cheap, sustainable, and efficient electricity generation. In the present work, we calculate the solar-generated shift current and efficiencies in 326 different 2D materials obtained from the computational database C2DB. We apply, as metrics, the efficiencies of monolayer and multilayer samples. The monolayer efficiencies are generally found to be low, while the multilayer efficiencies of infinite stacks show great promise. Furthermore, the out-of-plane shift current response is considered, and material candidates for efficient out-of-plane shift current devices are identified. Among the screened materials, MXY Janus and MX2 transition metal dichalchogenides (TMDs) constitute a prominent subset, with chromium based MXY Janus TMDs holding particular promise. Finally, in order to explain the band gap dependence of the PV efficiency, a simple gapped graphene model with a variable band gap is established and related to the calculated efficiencies.

Quasi-One-Dimensional van der Waals Transition Metal Trichalcogenides.

The transition metal trichalcogenides (TMTCs) are quasi-one-dimensional (1D) MX3-type van der Waals layered semiconductors, where M is a transition metal element of groups IV and V, and X indicates chalcogen element. Due to the unique quasi-1D crystalline structures, they possess several novel electrical properties such as variable bandgaps, charge density waves, and superconductivity, and highly anisotropic optical, thermoelectric, and magnetic properties. The study of TMTCs plays an essential role in the 1D quantum materials field, enabling new opportunities in the material research dimension. Currently, tremendous progress in both materials and solid-state devices has been made, demonstrating promising applications in the realization of nanoelectronic devices. This review provides a comprehensive overview to survey the state of the art in materials, devices, and applications based on TMTCs. Firstly, the symbolic structure, current primary synthesis methods, and physical properties of TMTCs have been discussed. Secondly, examples of TMTC applications in various fields are presented, such as photodetectors, energy storage devices, catalysts, and sensors. Finally, we give an overview of the opportunities and future perspectives for the research of TMTCs, as well as the challenges in both basic research and practical applications.

Epitaxy growth of MAPbBrxCl3−x single-crystalline perovskite films toward spectral selective detection in both broadband and narrowband ranges

Single-crystalline perovskite films with continuous variable bandgaps were grown by liquid phase epitaxy. The planar-type photodetectors present two kind detection mode of broadband and narrowband by manipulating the light incident direction.