Photoelectric Semiconductor Research Articles

Donor-Acceptor-π-Acceptor-Donor-Type Photosensitive Covalent Organic Framework for Effective Photocatalytic Aerobic Oxidation.

Developing effective photocatalysts for the oxidation reaction is of great significance in chemical synthesis but is still challenging. Herein, linking photochromic triphenylamine with pyrene units by the in situ formed robust imidazole moieties, a covalent organic framework (COF), PyNTB-COF, containing a rare donor-acceptor-π-acceptor-donor (D-A-π-A-D) fragment, was successfully synthesized for photocatalytic aerobic oxidation. Structure characterizations confirm its crystalline framework, high porosity, and good stability. Property studies reveal its photoelectric semiconductor feature with high photoresponsive charge separation and migration activity derived from the D-A-π-A-D fragments, proven by the experimental results and theoretical calculations. Photocatalytic experiments not only display its highly effective photoresponsive activity in triggering the generation of ·O2- under visible light irradiation but also exhibit its high photocatalytic efficiency in the aerobic oxidations of toluene and the amidation of aldehydes. This work demonstrates that the integration of photochromic units into framework materials to construct π-conjugated D-A moieties could enhance photocatalytic charge separation and migration efficiency, achieving promising photocatalysts for photocatalytic aerobic oxidation.

Engineering the structural, electronic, and optical properties of the novel monolayer photoelectric semiconductor C2/m-SnX (X = P, as) via strain: a first-principles study

Engineering the structural, electronic, and optical properties of the novel monolayer photoelectric semiconductor C2/m-SnX (X = P, as) via strain: a first-principles study

A novel two-dimensional all-carbon Dirac node-line semimetal

Carbon allotropes have vast potential in various applications, including superconductivity, energy storage, catalysis, and photoelectric semiconductor devices. Recently, there has been significant research interest in exploring new carbon materials that exhibit unique electronic structures. Here, we propose a novel two-dimensional (2D) carbon allotrope called TCH-SSH-2D, which possesses a Dirac node-line (DNL) semimetallic state. The structure of TCH-SSH-2D is derived from the TCH-type Archimedean polyhedral carbon cluster units, combined with the SSH lattice model, possessing a space group of tetragonal P4/mmm. Using first-principles calculations, we demonstrate that the system is dynamically, thermodynamically, and mechanically stable. It exhibits an energetically favorable structure with no imaginary frequency in the phonon dispersion curves and elastic constants satisfying the Born-Huang stability criterion. Our findings not only contribute to a deeper understanding of the carbon allotrope family but also provide an opportunity to explore unique Dirac states in two-dimensional pure carbon systems.

Pressure-induced superconductivity in the photoelectric semiconductor BiSeI

${A}^{\mathrm{V}}\phantom{\rule{0.16em}{0ex}}{B}^{\mathrm{VI}}\phantom{\rule{0.16em}{0ex}}{C}^{\mathrm{VII}}$ ($A=\mathrm{Bi}$, Sb; $B=\mathrm{S}$, Se; $C=\mathrm{I}$, Br) semiconductors are promising materials in photoelectric applications and exhibit high tunability of electronic properties. Here, we systematically study the electrical transport, structural, and vibrational properties of photoelectric semiconductor BiSeI at high pressure. With increasing pressure, a small drop in the resistance curve starts to appear at ${P}_{\mathrm{C}}\ensuremath{\sim}27.4$ GPa and zero resistance conductivity is eventually achieved at 40.4 GPa, indicating the occurrence of a superconducting transition. Combined with high-pressure Raman scattering, synchrotron XRD measurements, and theoretical calculations, we demonstrate that this superconductivity originates from a high-pressure phase with space group $P4$/nmm. Upon further compression, ${T}_{C}$ initially increases and then changes marginally with a nearly constant 5.6 K above 40.0 GPa, suggesting the robustness of this superconductivity. Our findings will shed light on exploring exotic properties in low-dimensional systems via pressure treatment.

Ultrasensitive Photoelectrochemical Immunoassay Strategy Based on Bi2S3/Ag2S for the Detection of the Inflammation Marker Procalcitonin

As an inflammatory marker, procalcitonin (PCT) is more representative than other traditional inflammatory markers. In this work, a highly efficient photoelectrochemical (PEC) immunosensor was constructed based on the photoactive material Bi2S3/Ag2S to realize the sensitive detection of PCT. Bi2S3 was prepared by a hydrothermal method, and Ag2S quantum dots were deposited on the ITO/Bi2S3 surface via in situ reduction. Bi2S3 is a kind of admirable photoelectric semiconductor nanomaterial on account of its moderate bandgap width and low binding rate of photogenerated electron holes, which can effectively convert light energy into electrical energy. Therefore, based on the energy level matching principle of Bi2S3 and Ag2S, a labeled Bi2S3/Ag2S PEC immunosensor was constructed, and the sensitive detection of PCT was successfully established. The linear detection range of the PEC immunosensor was 0.50 pg∙mL-1 to 50 ng∙mL-1, and the minimum detection limit was 0.18 pg∙mL-1. Compared with the traditional PEC strategy, the proposed PEC immunosensor is simple, convenient, and has good anti-interference, sensitivity, and specificity, which could provide a meaningful theoretical basis and reference value for the clinical detection of PCT.

Pyrene-Fused Poly-Aromatic Regioisomers: Synthesis, Columnar Mesomorphism, and Optical Properties.

π-Extended pyrene compounds possess remarkable luminescent and semiconducting properties and are being intensively investigated as electroluminescent materials for potential uses in organic light-emitting diodes, transistors, and solar cells. Here, the synthesis of two sets of pyrene-containing π-conjugated polyaromatic regioisomers, namely 2,3,10,11,14,15,20,21-octaalkyloxypentabenzo[a,c,m,o,rst]pentaphene (BBPn) and 2,3,6,7,13,14,17,18-octaalkyloxydibenzo[j,tuv]phenanthro [9,10-b]picene (DBPn), is reported. They were obtained using the Suzuki-Miyaura cross-coupling in tandem with Scholl oxidative cyclodehydrogenation reactions from the easily accessible precursors 1,8- and 1,6-dibromopyrene, respectively. Both sets of compounds, equipped with eight peripheral aliphatic chains, self-assemble into a single hexagonal columnar mesophase, with one short-chain BBPn homolog also exhibiting another columnar mesophase at a lower temperature, with a rectangular symmetry; BBPn isomers also possess wider mesophase ranges and higher mesophases' stability than their DBPn homologs. These polycyclic aromatic hydrocarbons all show a strong tendency of face-on orientation on the substrate and could be controlled to edge-on alignment through mechanical shearing of interest for their implementation in photoelectronic devices. In addition, both series BBPn and DBPn display green-yellow luminescence, with high fluorescence quantum yields, around 30%. In particular, BBPn exhibit a blue shift phenomenon in both absorption and emission with respect to their DBPn isomers. DFT results were in good agreement with the optical properties and with the stability ranges of the mesophases by confirming the higher divergence from the flatness of DBPn compared with BBPn. Based on these interesting properties, these isomers could be potentially applied not only in the field of fluorescent dyes but also in the field of organic photoelectric semiconductor materials as electron transport materials.

Electronic, optical, and transport properties of single-layer ZrTeS4: a DFT study

ZrTeS4 is a promising photoelectric semiconductor with a tunable band gap and high ultra-violet absorption rate.

Influence of the Building Unit on Covalent Organic Frameworks in Mediating Photo-induced Energy-Transfer Reversible Complexation-Mediated Radical Polymerization (PET-RCMP).

Two imine-based covalent organic framework photocatalysts with different building units, TPB-DMTA-COF and TAT-DMTA-COF, for photo-induced energy transfer reversible complexation-mediated radical polymerization (PET-RCMP) were developed and investigated, producing ideal polymers with accurate molecular weight and moderate dispersity under visible light irradiation. The chain extension and spatiotemporal control experiments revealed the high chain-end fidelity of polymers and the compatibility of RCMP processes in both bulk and aqueous system. Moreover, density functional theory (DFT) calculations verified that heteroatom-doped TAT-DMTA-COF exhibits higher activities for weakening C-I bond energy barrier, which promotes PET-RCMP polymerization performance. This work demonstrates that rational adjustment of building block for constructing COF heterogeneous photocatalyst can enhance the catalytic performance of PET-RCMP, providing a design methodology for the development of polymeric organic photoelectric semiconductor catalysts to mediate RCMP.

Influence of the Building Unit on Covalent Organic Frameworks in Mediating Photo‐induced Energy‐Transfer Reversible Complexation‐Mediated Radical Polymerization (PET‐RCMP)

AbstractTwo imine‐based covalent organic framework photocatalysts with different building units, TPB‐DMTA‐COF and TAT‐DMTA‐COF, for photo‐induced energy transfer reversible complexation‐mediated radical polymerization (PET‐RCMP) were developed and investigated, producing ideal polymers with accurate molecular weight and moderate dispersity under visible light irradiation. The chain extension and spatiotemporal control experiments revealed the high chain‐end fidelity of polymers and the compatibility of RCMP processes in both bulk and aqueous system. Moreover, density functional theory (DFT) calculations verified that heteroatom‐doped TAT‐DMTA‐COF exhibits higher activities for weakening C−I bond energy barrier, which promotes PET‐RCMP polymerization performance. This work demonstrates that rational adjustment of building block for constructing COF heterogeneous photocatalyst can enhance the catalytic performance of PET‐RCMP, providing a design methodology for the development of polymeric organic photoelectric semiconductor catalysts to mediate RCMP.

Effects of preparation parameters on growth and properties of β-Ga2O3 film

The Ga2O3 films are deposited on the Si and quartz substrates by magnetron sputtering, and annealing. The effects of preparation parameters (such as argon–oxygen flow ratio, sputtering power, sputtering time and annealing temperature) on the growth and properties (e.g., surface morphology, crystal structure, optical and electrical properties of the films) are studied by x-ray diffractometer (XRD), scanning electron microscope (SEM), and ultraviolet-visible spectrophotometer (UV-Vis). The results show that the thickness, crystallization quality and surface roughness of the β-Ga2O3 film are influenced by those parameters. All β-Ga2O3films show good optical properties. Moreover, the value of bandgap increases with the enlarge of the percentage of oxygen increasing, and decreases with the increase of sputtering power and annealing temperature, indicating that the bandgap is related to the quality of the film and affected by the number of oxygen vacancy defects. The I–V curves show that the Ohmic behavior between metal and β-Ga2O3 films is obtained at 900 °C. Those results will be helpful for the further research of β-Ga2O3 photoelectric semiconductor.

Layered post-transition-metal dichalcogenide SnGe2N4 as a promising photoelectric material: a DFT study.

First-principles calculations were performed to study a novel layered SnGe2N4 compound, which was found to be dynamically and thermally stable in the 2H phase, with the space group P6̄m2 and lattice constant a = 3.143 Å. Due to its hexagonal structure, SnGe2N4 exhibits isotropic mechanical properties on the x–y plane, where the Young’s modulus is 335.49 N m−1 and the Poisson’s ratio is 0.862. The layered 2H SnGe2N4 is a semiconductor with a direct band gap of 1.832 eV, allowing the absorption of infrared and visible light at a rate of about 104 cm−1. The DOS is characterized by multiple high peaks in the valence and conduction bands, making it possible for this semiconductor to absorb light in the ultraviolet region with an even higher rate of 105 cm−1. The band structure, with a strongly concave downward conduction band and rather flat valence band, leads to a high electron mobility of 1061.66 cm2 V−1 s−1, which is substantially greater than the hole mobility of 28.35 cm2 V−1 s−1. This difference in mobility is favorable for electron–hole separation. These advantages make layered 2H SnGe2N4 a very promising photoelectric material. Furthermore, the electronic structure of 2H SnGe2N4 responds well to strain and an external electric field due to the specificity of the p–d hybridization, which predominantly constructs the valence bands. As a result, strain and external electric fields can efficiently tune the band gap value of 2H SnGe2N4, where compressive strain widens the band gap, meanwhile tensile strain and external electric fields cause band gap reduction. In particular, the band gap is decreased by about 0.25 eV when the electric field strength increases by 0.1 V Å−1, making a semiconductor–metal transition possible for the layered SnGe2N4.

Construction of direct Z-scheme photocatalyst by the interfacial interaction of WO3 and SiC to enhance the redox activity of electrons and holes

Construction of direct Z-scheme photocatalyst by the interfacial interaction of WO3 and SiC to enhance the redox activity of electrons and holes

Effect of Halogen‐Doping on Properties of Bismuth Iodide (BiI3) Optical Absorption Layer

Bismuth tri‐iodide (BiI3), a promising lead‐free photoelectric semiconductor material, is suitable for photovoltaic applications. Herein, the effect of halogen doping with bromine (Br) and chlorine (Cl) compounds on the morphology and photovoltaic performances of BiI3 thin films is investigated. BiI3−xXx films doped with halogens are prepared by vacuum thermal evaporation. Scanning electron microscope (SEM) shows that with the increase in doping ratio, the morphology of the thin film changes significantly, which is conducive to the contact with the cavity conduction layer. The bandgap increases from ≈1.75 to 1.78 eV (BiI2.91Cl0.09) and 2.06 eV (BiI2.91Br0.09) after doping. X‐ray photoelectron spectroscopy (XPS) shows that the band position of the two doped films increases, which is more conducive to the realization of band matching. The films with higher properties are obtained by doping halogens, and the maximum (BiI2.91X0.09) photocurrent is twice of the minimum (BiI2.97X0.03). The maximum photocurrent obtained by photocurrent I–T test is 0.043 Ma cm−2 (BiI2.91Cl0.09) and 0.047 mA cm−2 (BiI2.91Br0.09).

Photon‐Memristive System for Logic Calculation and Nonvolatile Photonic Storage

AbstractMemristor‐based architectures have shown great potential for developing future computing systems beyond the era of von Neumann and Moore's law. However, the monotonous electrical input for dynamic resistance regulation limits the developments of memristors. Here, a concept of a photon‐memristive system, which realizes memristance depending on number of photons (optical inputs), is proposed. A detailed theoretical derivation is performed and the memristive characteristics, as stimulated by the optical inputs based on a hybrid system, consisting of a low‐dimension photoelectric semiconductor and a ferroelectric substrate are determined. The photon‐memristive system is also suitable for nonvolatile photonic memory since it possesses three or more‐bit data storage, desirable resistance‐change space, and an ON/OFF ratio of nearly 107. The integrated circuit based on several photon‐memristive systems also realizes available photon‐triggered in‐memory computing. The photon‐memristive system expands the definition of memristors and emerges as a new data storage cell for future photonic neuromorphic computational architectures.

Designing and controlling the metrological parameters of photoelectric transducers based on semiconductors with multiply-charged dopants

The initial data for designing the metrological parameters of photoelectric semiconductor transducers (PST) based on semiconductors with deep multiply-charged dopants are obtained. The ranges of correspondence between the energy characteristic of PST with multiply-charged dopants and the linear operation mode are studied. It is demonstrated that an appropriate choice of a deep multiply-charged dopant enables designing an PST with a given pass band, an improved signal/noise ratio and a higher operating temperature. Moreover, it is shown that combining control and measuring optical channels in a single photodetector allows for implementing the control method for the PST spectral sensitivity during operation.

Design of a Reverse-Connected Module for Nanostructure Removal From Display Color Filters

This paper proposes a new design module for reverse-connected microelectrochemical machining (μ-ECM), which is based on a novel electrochemical reaction that offers the fast removal of indium-tin-oxide (ITO) nanostructures from the surfaces of color filters in displays. Unlike general μ-ECM models, the reverse-connected μ-ECM model is implemented by connecting a workpiece to the cathode and an electrode to the anode of a dc power supply. During the course of machining, electrons travel from the cathode to the anode, so that the ITO film is lifted and removed at high speed by an electric field. In general μ-ECM models, a workpiece is connected to the anode, an electrode is connected to the cathode, and the material removal is achieved by dissolution. In contrast, the reverse-connected μ-ECM model provides higher removal efficiency and higher surface quality of color filters in displays during machining processes, thereby breaking new ground in superfine machining for applications in the photoelectric semiconductor industry.

Numerical method and analysis of computational fluid mechanics for photoelectric semiconducting detector

We propose a modified upwind finite difference fractional step scheme for the computational fluid mechanics simulations of a three-dimensional photoelectric semiconductor detector. We obtain the optimal l2-norm error estimates by using the techniques including the calculus of variations, the energy methods, the induction hypothesis, and a priori estimates. The proposed scheme is successfully applied to the simulation of the photoelectric semiconductor detectors.

Plasma model of carrier transportation in photoelectric semiconductor detectors

A new model, called the plasma model, describing carrier transportation in photoelectric semiconductor detectors is proposed. Semiconductor material under laser irradiation is regarded as a plasma of low temperature with high carrier density, and it is considered that the carrier temperature is different from the lattice temperature when the irradiating laser power is high but lower than the damage threshold of the detectors. Equations for the carrier density, velocity and temperature are established. According to the model, numerical simulations of a photoconductive semiconductor detector were carried out by programming. The instantaneous change behaviors of the photoconductive detector are obtained. The results of the numerical calculation match well with the experimental results.

Determination of low levels of uranium impurity by fission track registration using mica and polycarbonate detectors

Determination of low levels of uranium impurity by fission track registration using mica and polycarbonate detectors

A specific embedding resin (PVK) for fine cytological investigations in the photoemission electron microscope

A specific embedding resin (PVK) for fine cytological investigations in the photoemission electron microscope