Metal-Free Catalytic Formation of a Donor-Acceptor-Donor Molecule and Its Lewis Acid-Adduct Singlet Diradical with High-Efficient NIR-II Photothermal Conversion

We have synthesized a quinone-incorporated bistriarylamine donor-acceptor-donor (D-A-D) semiconductor 1 by B(C6F5)3 (BCF) catalyzed C-H/C-H cross coupling via radical ion pair intermediates. Coordination of Lewis acids BCF and Al(ORF)3 (RF=C(CF3)3) to the semiconductor 1 afforded diradical zwitterions 2 and 3 by integer electron transfer. Upon binding to Lewis acids, the LUMO energy of 1 is significantly lowered and the band gap of the semiconductor is significantly narrowed from 1.93 eV (1) to 1.01 eV (2) and 1.06 eV (3). 2 and 3 are rare near-infrared (NIR) diradical dyes with broad absorption both centered around 1500 nm. By introducing a photo BCF generator, 2 can be generated by light-dependent control. Furthermore, the integer electron transfer process can also be reversibly regulated via the addition of CH3CN. In addition, the temperature of 2 sharply increased and reached as high as 110 °C in 10 s upon the irradiation of near-infrared-II (NIR-II) laser (1064 nm, 0.7 W cm-2), exhibiting a fast response to laser. It displays excellent photothermal stability with a photothermal (PT) conversion efficiency of 62.26 % and high-quality PT imaging.

Electronic Structure Analysis of the A10Tt2P6 System (A=Li-Cs; Tt=Si, Ge, Sn) and Synthesis of the Direct Band Gap Semiconductor K10Sn2P6

Investigating the relationship between atomic and electronic structures is a powerful tool to screen the wide variety of Zintl phases for interesting (opto-)electronic properties. To get an insight in such relations, the A10Tt2P6 system (A=Li-Cs; Tt=Si-Sn) was picked as model system to analyse the influence of structural motives, combination of elements and their properties on type and width of the band gaps. Those compounds comprise two interesting structural motives of their anions, which are either monomeric trigonal planar TtP3 5- units which are isostructural to CO3 2- or [Tt2P6]10- dimers which correspond to two edge-sharing TtP4 tetrahedra. The A10Tt2P6 compounds were structurally optimized for both polymorphs and subsequent frequency analysis, band structure as well as density of states calculations were performed. The Gibbs free energies were compared to determine temperature dependent stability, where Na10Si2P6, Na10Ge2P6 and K10Sn2P6 were found to be candidates for a high temperature phase transition between the two polymorphs. Additionally, the unknown, but predicted compound K10Sn2P6 was synthesized and characterized by single crystal and powder x-ray diffraction. It crystalizes in the monoclinic space group P 21/n and incorporates [Sn2P6]10- edge sharing double tetrahedra. It was determined to be a direct band gap semiconductor with a band gap of 2.57 eV.

YOLOv5 based object detection in reel package X-ray images of semiconductor component

The industrial manufacturing landscape is currently shifting toward the incorporation of technologies based on artificial intelligence (AI). This transition includes an evolution toward smart factory infrastructure, with a specific focus on AI-driven strategies in production and quality control. Specifically, AI-empowered computer vision has emerged as a potent tool that offers a departure from extant rule-based systems and provides enhanced operational efficiency at manufacturing sites. As the manufacturing sector embraces this new paradigm, the impetus to integrate AI-integrated manufacturing is evident. Within this framework, one salient application is AI deep learning-facilitated small-object detection, which is poised to have extensive implications for diverse industrial applications. This study describes an optimized iteration of the YOLOv5 model, which is known for its efficacious single-stage object-detection abilities underpinned by PyTorch. Our proposed "improved model" incorporates an additional layer to the model's canonical three-layer architecture, augmenting accuracy and computational expediency. Empirical evaluations using semiconductor X-ray imagery reveal the model's superior performance metrics. Given the intricate specifications of surface-mount technologies, which are characterized by a plethora of micro-scale components, our model makes a seminal contribution to real-time, in-line production assessments. Quantitative analyses show that our improved model attained a mean average precision of 0.622, surpassing YOLOv5's 0.349, and a marked accuracy enhancement of 0.865, which is a significant improvement on YOLOv5's 0.552. These findings bolster the model's robustness and potential applicability, particularly in discerning objects at reel granularities during real-time inferencing.

Assessment of Occupational Health Risks for Maintenance Work in Fabrication Facilities: Brief Review and Recommendations

Background

This study focuses on assessing occupational risk for the health hazards encountered during maintenance works (MW) in semiconductor fabrication (FAB) facilities.

Objectives

The objectives of this study include: 1) identifying the primary health hazards during MW in semiconductor FAB facilities; 2) reviewing the methods used in evaluating the likelihood and severity of health hazards through occupational health risk assessment (OHRA); and 3) suggesting variables for the categorization of likelihood of exposures to health hazards and the severity of health effects associated with MW in FAB facilities.

Methods

A literature review was undertaken on OHRA methodology and health hazards resulting from MW in FAB facilities. Based on this review, approaches for categorizing the exposure to health hazards and the severity of health effects related to MW were recommended.

Results

Maintenance workers in FAB facilities face exposure to hazards such as debris, machinery entanglement, and airborne particles laden with various chemical components. The level of engineering and administrative control measures is suggested to assess the likelihood of simultaneous chemical and dust exposure. Qualitative key factors for mixed exposure estimation during MW include the presence of safe operational protocols, the use of air-jet machines, the presence and effectiveness of local exhaust ventilation system, chamber post-purge and cooling, and proper respirator use. Using the risk (R) and hazard (H) codes of the Globally Harmonized System alongside carcinogenic, mutagenic, or reprotoxic classifications aid in categorizing health effect severity for OHRA.

Conclusion

Further research is needed to apply our proposed variables in OHRA for MW in FAB facilities and subsequently validate the findings.

Photocatalytic Enhancement Strategy with the Introduction of Metallic Bi: A Review on Bi/Semiconductor Photocatalysts

Semiconductor photocatalysis has great potential in the fields of solar fuel production and environmental remediation. Nevertheless, the photocatalytic efficiency still constrains its practical production applications. The development of new semiconductor materials is essential to enhance the solar energy conversion efficiency of photocatalytic systems. Recently, the research on enhancing the photocatalytic performance of semiconductors by introducing bismuth (Bi) has attracted widespread attention. In this review, we briefly overview the main synthesis methods of Bi/semiconductor photocatalysts and summarize the control of the micromorphology of Bi in Bi/semiconductors and the key role of Bi in the catalytic system. In addition, the promising applications of Bi/semiconductors in photocatalysis, such as pollutant degradation, sterilization, water separation, CO2 reduction, and N2 fixation, are outlined. Finally, an outlook on the challenges and future research directions of Bi/semiconductor photocatalysts is given. We aim to offer guidance for the rational design and synthesis of high-efficiency Bi/semiconductor photocatalysts for energy and environmental applications.

A flexible semiconductor SERS substrate by in situ growth of tightly aligned TiO2 for in situ detection of antibiotic residues

Semiconductor materials have become a competitive candidate for surface-enhanced Raman scattering (SERS) substrate. However, powdered semiconductors are difficult to execute a fast in situ detection for trace analytes. Here, we developed a new flexible semiconductor SERS substrate by in situ densely growing anatase TiO2 nanoparticles on the surface of cotton fabric through a filtration-hydrothermal method, in which TiO2 exhibits excellent controllability in size and distribution by regulating the ratio of water to alcohol in synthesis and the number of filtration-hydrothermal repetitive cycle. Cotton fabric/TiO2 (Cot/TiO2) substrate exhibits a high SERS activity and excellent spectral repeatability. The developed substrate has an ultra-high stability that can withstand long-term preservation; it can even resist the corrosions of strong acid and alkali, as well as high temperature up to 100 °C and low temperature down to - 20 °C. The flexible substrate can be used to carry out a rapid in situ detection for quinolone antibiotic (enrofloxacin and enoxacin) residues on the fish body surface by using a simple swabbing method, with high quantitative detection potential (up to an order of magnitude of 10-7 M), and even for the simultaneous detection of both drug residues. The flexible substrate also exhibits an excellent recyclability up to 6 recycles in the actual SERS detection.

Effect of tin concentrations on the elemental and optical properties of zinc oxide thin films

Pure zinc oxide and Sn-doped ZnO thin films were deposited on a pre-heated glass substrate from tin (II) chloride dihydrate (SnCl2.2H2O) and zinc acetate (Zn(CH3COO))2 precursors using spray pyrolysis technique. The doped films were achieved by adding various quantities of (SnCl2. 2H2O) precursor to the solution of zinc acetate in volume percent range of 0-10. Rutherford Backscattering Spectrometry (RBS) was used to characterise the prepared films to determine their thickness and elemental composition. To examine the films' optical characteristics, a UV spectrometer operating at room temperature and covering a wavelength range of 300-1100 nm was employed. The film's thickness and composition show that as the volume of Sn in the thin films increases, so does the film's thickness. With average transmittance values up to 70 %, all the films are quite transparent in the visible region of the electromagnetic spectrum and have a significant UV cut-off at roughly 380 nm. The reflectivity of Sn-doped ZnO films is seen to be independent of the volume of Sn in the films, and the reflectivity of the films diminishes as the wavelength increases. Sn-doped ZnO thin film has an optical band gap of 3.14-3.18 eV. The properties of the thin film produced make it suitable for solar energy collection and improve the efficiency of solar energy system, various optoelectronics devices and sensor.

Synthesis of two-dimensional triazine covalent organic frameworks at ambient conditions to detect and remove water pollutants

Synthesis of fully triazine frameworks (C3N3) by metal catalyzed reactions at high temperatures results in carbonized and less-defined structures. Moreover, metal impurities affect the physicochemical, optical and electrical properties of the synthesized frameworks, dramatically. In this work, two-dimensional C3N3 (2DC3N3) has been synthesized by in situ catalyst-free copolymerization of sodium cyanide and cyanuric chloride, as cheap and commercially available precursors, at ambient conditions on gram scale. Reaction between sodium cyanide and cyanuric chloride resulted in electron-poor polyfunctional intermediates, which converted to 2DC3N3 with several hundred micrometers lateral size at ambient conditions upon [2 + 2+2] cyclotrimerization. 2DC3N3 sheets, in bulk and individually, showed strong fluorescence with 63% quantum yield and sensitive to small objects such as dyes and metal ions. The sensitivity of 2DC3N3 emission to foreign objects was used to detect low concentration of water impurities. Due to the high negative surface charge (-37.7 mV) and dispersion in aqueous solutions, they demonstrated a high potential to remove positively charged dyes from water, exemplified by excellent removal efficiency (>99%) for methylene blue. Taking advantage of the straightforward production and strong interactions with dyes and metal ions, 2DC3N3 was integrated in filters and used for the fast detection and efficient removal of water impurities.

Role of oxygen vacancies in ferroelectric or resistive switching hafnium oxide

HfO2 shows promise for emerging ferroelectric and resistive switching (RS) memory devices owing to its excellent electrical properties and compatibility with complementary metal oxide semiconductor technology based on mature fabrication processes such as atomic layer deposition. Oxygen vacancy (Vo), which is the most frequently observed intrinsic defect in HfO2-based films, determines the physical/electrical properties and device performance. Vo influences the polymorphism and the resulting ferroelectric properties of HfO2. Moreover, the switching speed and endurance of ferroelectric memories are strongly correlated to the Vo concentration and redistribution. They also strongly influence the device-to-device and cycle-to-cycle variability of integrated circuits based on ferroelectric memories. The concentration, migration, and agglomeration of Vo form the main mechanism behind the RS behavior observed in HfO2, suggesting that the device performance and reliability in terms of the operating voltage, switching speed, on/off ratio, analog conductance modulation, endurance, and retention are sensitive to Vo. Therefore, the mechanism of Vo formation and its effects on the chemical, physical, and electrical properties in ferroelectric and RS HfO2 should be understood. This study comprehensively reviews the literature on Vo in HfO2 from the formation and influencing mechanism to material properties and device performance. This review contributes to the synergetic advances of current knowledge and technology in emerging HfO2-based semiconductor devices.

Surface-Degenerate Semiconductor Photocatalysis for Efficient Water Splitting without Sacrificial Agents via a Reticular Chemistry Approach

The production of green hydrogen through photocatalytic water splitting is crucial for a sustainable hydrogen economy and chemical manufacturing. However, current approaches suffer from slow hydrogen production (<70 μmol ⋅ gcat -1  ⋅ h-1 ) due to the sluggish four-electrons oxygen evolution reaction (OER) and limited catalyst activity. Herein, we achieve efficient photocatalytic water splitting by exploiting a multifunctional interface between a nano-photocatalyst and metal-organic framework (MOF) layer. The functional interface plays two critical roles: (1) enriching electron density directly on photocatalyst surface to promote catalytic activity, and (2) delocalizing photogenerated holes into MOF to enhance OER. Our photocatalytic ensemble boosts hydrogen evolution by ≈100-fold over pristine photocatalyst and concurrently produces oxygen at ideal stoichiometric ratio, even without using sacrificial agents. Notably, this unique design attains superior hydrogen production (519 μmol ⋅ gcat -1  ⋅ h-1 ) and apparent quantum efficiency up to 13-fold and 8-fold better than emerging photocatalytic designs utilizing hole scavengers. Comprehensive investigations underscore the vital role of the interfacial design in generating high-energy photoelectrons on surface-degenerate photocatalyst to thermodynamically drive hydrogen evolution, while leveraging the nanoporous MOF scaffold as an effective photohole sink to enhance OER. Our interfacial approach creates vast opportunities for designing next-generation, multifunctional photocatalytic ensembles using reticular chemistry with diverse energy and environmental applications.

Assessing the contribution of semiconductors to the sustainable development goals (SDGs) from 2017 to 2022

Semiconductor development is a major driving force for global economic growth. However, synchronizing it with the Sustainable Development Goals (SDGs) set by the United Nations remains a critical challenge. To gain insight into this, we analyzed SDG-related publications on semiconductors from 2017 to 2022 using the SciVal database. The study found 77,706 documents related to SDGs in the field of semiconductor research, with an overall increase in the number of publications each year. The main focus of these publications was SDG 7 (Affordable and Clean Energy), accounting for 68.9 % of the total publication count. Additionally, the results indicate that semiconductors have multifaceted potential in advancing a range of SDGs. From fostering innovations in healthcare (SDG 3), ensuring clean water access (SDG 6), catalyzing transformative industrial growth (SDG 9), to contributing to climate mitigation strategies (SDG 13), semiconductors emerge as versatile drivers of sustainable development. The respective publication percentages for these goals were 7.3 %, 5.9 %, 9.7 %, and 4.4 %, underscoring their capacity to make substantial contributions across various facets of sustainability. It's worth noting that only 2.9 % of these publications stem from academia-industry collaborations. This indicates a pressing need to facilitate collaboration between academia and industry, as such partnerships have the potential to amplify the impact of semiconductor innovations on the SDGs. The novelty of this study lies in its specific exploration through a comprehensive analysis spanning five years, revealing the alignment between semiconductor advancements and the latest SDGs. It uncovers the significance of collaborative ecosystems involving research institutions, businesses, and governments. Through these results, our study addresses a gap in the existing literature and advances semiconductor contributions to the SDGs.

Graphene-based photocatalysts for degradation of organic pollution

Compared with the traditional wastewater treatment technology, semiconductor photocatalysis is a rapidly emerging environment-friendly and efficient Advanced Oxidation Process for degradation of refractory organic contaminants. Single-component semiconductor photocatalysts exhibit poor photocatalytic performance and cannot meet the requirements of wastewater treatment. The combination of semiconductor photocatalysts and Graphene can effectively improve the photocatalytic activity and stability of semiconductor photocatalysts. This review focuses on the synergistic effect of several types of semiconductors with Graphene for photocatalytic degradation of organic pollutants. After a brief introduction of the photodegradation mechanism of semiconductor materials and the basic description of Graphene, the synthesis, characterization and degradation performance of various Graphene-based semiconductor photocatalysts are emphatically introduced.

Nanomaterials for photo-electrochemical water splitting: a review

Over the last few decades, the global rise in energy demand has prompted researchers to investigate the energy requirements from alternative green fuels apart from the conventional fossil fuels, due to the surge in CO2 emission levels. In this context, the global demand for hydrogen is anticipated to extend by 4-5% in the next 5 years. Different production technologies like gasification of coal, partial oxidation of hydrocarbons, and reforming of natural gas are used to obtain high yields of hydrogen. In present time, 96% of hydrogen is produced by the conventional methods, and the remaining 4% is produced by the electrolysis of water. Photo-electrochemical (PEC) water splitting is a promising and progressive solar-to-hydrogen pathway with high conversion efficiency at low operating temperatures with substrate electrodes such as fluorine-doped tin oxide (FTO), incorporated with photocatalytic nanomaterials. Several semiconducting nanomaterials such as carbon nanotubes, TiO2, ZnO, graphene, alpha-Fe2O3, WO3, metal nitrides, metal phosphides, cadmium-based quantum dots, and rods have been reported for PEC water splitting. The design of photocatalytic electrodes plays a crucial role for efficient PEC water splitting process. By modifying the composition and morphology of photocatalytic nanomaterials, the overall solar-to-hydrogen (STH) energy conversion efficiency can be improved by optimizing their opto-electronic properties. The present article highlights the recent advancements in cleaner and effective photocatalysts for producing high yields of hydrogen via PEC water splitting.

Analysis of the photocatalytic activity of La0.9Sr0.1Fe0.8Co0.2O3±δ perovskite as a catalyst in the degradation of RB-5 dye

The photocatalytic efficiency of some semiconductors depends mainly on their morphological, optical, and structural properties, which can be modified by varying the calcination temperature. In order to evaluate how these properties change, as a function of temperature in a AA'BB'O3 perovskite material, La0.9Sr0.1Fe0.8Co0.2O3±δ (LSFC) was synthesized by the Pechini method and calcined at different temperatures (600 °C, 700 °C, 800 °C, and 900 °C). All the samples were characterized structurally, morphologically, and optically by XRD, SEM, and UV-Vis spectroscopy. Additionally, specific surface area and pore size distribution were calculated by BET and BHJ methods. LSFC was evaluated as photocatalyst material, estimating the degradation of reactive black 5 (RB5), employing as irradiation source UV light and sunlight. The obtained results display a clear tendency between the photoactivity and the heat treatment: degradation percentage decreases as the calcination temperature increases mainly due to the crystal and grain size and, furthermore, loss of porosity and the decrease in surface area, affecting the photocatalytic activity (98%, 95%, 74%, and 50% degradation, respectively). All the ceramic samples follow a pseudo-first-order reaction.

Plasmon-Induced Charge Transfer-Enhanced Raman Scattering on a Semiconductor: Toward Amplification-Free Quantification of SARS-CoV-2

Semiconductors demonstrate great potentials as chemical mechanism-based surface-enhanced Raman scattering (SERS) substrates in determination of biological species in complex living systems with high selectivity. However, low sensitivity is the bottleneck for their practical applications, compared with that of noble metal-based Raman enhancement ascribed to electromagnetic mechanism. Herein, a novel Cu2 O nanoarray with free carrier density of 1.78×1021  cm-3 comparable to that of noble metals was self-assembled, creating a record in enhancement factor (EF) of 3.19×1010 among semiconductor substrates. The significant EF was mainly attributed to plasmon-induced hot electron transfer (PIHET) in semiconductor which was never reported before. This Cu2 O nanoarray was subsequently developed as a highly sensitive and selective SERS chip for non-enzyme and amplification-free SARS-CoV-2 RNA quantification with a detection limit down to 60 copies/mL within 5 min. This unique Cu2 O nanoarray demonstrated the significant Raman enhancement through PIHET process, enabling rapid and sensitive point-of-care testing of emerging virus variants.

Performance analysis of n-TiO2/p-Cu2O, n-TiO2/p-WS2/p-Cu2O, and n-TiO2/p-WS2 heterojunction solar cells through numerical modelling

A new hetero-structure of n-TiO2/p-WS2/p-Cu2O is proposed as a potential candidate for solar energy generation using tungsten disulfide (WS2) as an absorber layer. The proposed device performance is simulated by employing a one-dimensional solar cell capacitance simulator (SCAPS-1D). The numerical simulation studies compared the performances of n-TiO2/p-Cu2O, n-TiO2/p-WS2/p-Cu2O, and n-TiO2/p-WS2 hetero-structures based on various physical parameters like interface defects density, bulk defects density, absorber layer thickness, series resistance, shunt resistance, and operating temperature. In our simulation investigations, we found that interface defects pose a formidable impact on heterojunction devices. Interface defects closer to the front surface severely deteriorate the performances than the back surface. The bandgap of the absorber layer influences the performances of the solar cells. A closer comparison between n-TiO2/p-Cu2O and n-TiO2/p-WS2 heterojunction solar cells (HJSCs) revealed that the latter (n-TiO2/p-WS2) has nearly 182% better performance than the former (n-TiO2/p-Cu2O) devices. Additionally, the performance of the n-TiO2/p-WS2 solar cell is further boosted by ~ 139% in the presence of a hole transport layer of p-Cu2O. The best-simulated efficiency of the proposed new hetero-structure (n-TiO2/p-WS2/p-Cu2O) solar cell is 28.86%. Moreover, these optimized physical parameters may shed light on "easy to apply" new path for fabrication of a non-toxic, environment-friendly, and highly efficient novel thin-film heterojunction (n-TiO2/p-WS2/p-Cu2O) solar cell.

Organic waste peel-assisted synthesis of ZnSe nanoparticles for solar-driven photocatalytic degradation of cationic and anionic dye

The environment and public health are currently being threatened by the water pollution caused by dyes. Finding eco-friendly and economically viable photocatalysts has been a hot issue in recent years, as photocatalytic dye degradation is essential for eliminating dye from contaminated water as compared to other methods because of the cost factor and efficiency in removing organic contaminants. Using un-doped ZnSe for degrading activity has very seldom been attempted up to this point. Therefore, the current research focuses on the use of zinc selenide nanomaterials, which are produced via a green synthesis process from the organic waste peels of orange and potato using the hydrothermal method, and utilizes them as photocatalysts for the degradation of dyes using sunlight as a natural source of light. The crystal structure, bandgap, and surface morphology and analysis of the synthesized materials serve as indicators of their characteristics. Citrate in orange peel-mediated synthesis assists in forming a particle size of 1.85 nm and a large surface area of 17.078 m2/g enabling more surface-active sites resulting in degradation efficiency of 97.16% and 93.61% for methylene blue and Congo red dye, respectively, which outperforms commercial ZnSe in the dye degradation. The presented work maintains overall sustainability in real-practical applications by utilizing sunlight in photocatalytic degradation activity instead of sophisticated equipment and using waste peels as a capping and stabilizing agent in the green synthesis method for the preparation of photocatalysts.

Spatial Patterning of Micromotor Aggregation and Flux

Using a spatially varying light pattern with light activated semi-conductor based magnetic TiO2 micromotors, we study the difference in micromotor flux between illuminated and non-illuminated regions in the presence and absence of an applied magnetic field. We find that the magnetic field enhances the flux of the motors which we attribute to a straightening of the micromotor trajectories which decreases the time they spend in the illuminated region. We also demonstrate spatially patterned light-induced aggregation of the micromotors and study its time evolution at various micromotor concentrations. Although light induced aggregation has been observed previously, spatial patterning of aggregation demonstrates a further means of control which could be relevant to swarm control or self-assembly applications. Overall, these results draw attention to the effect of trajectory shape on the flux of active colloids as well as the concentration dependence of aggregation and its time dependence within a spatially patterned region, which is not only pertinent to self-assembly and swarm control, but also provides insight into the behavior of active matter systems with spatially varying activity levels.

Semiconductor-hydrophobic material interfaces as a new active site paradigm for photocatalytic degradation of perfluorocarboxylic acids

Photocatalytic degradation of long-chain perfluorocarboxylic acid (PFCA) water contaminants has been reported for numerous of semiconductors, including composite TiO₂ particles decorated with graphitic carbon co-catalysts. While pristine TiO₂ degrades PFCAs inefficiently, the carbon components purportedly enhance activity due to their conductive nature and resultant charge separation enhancement. Yet herein, we present evidence that the catalytic activity of a graphene oxide (GO)-TiO₂ composite from the literature arose not due to from charge separation, but to a unique mode of PFCA adsorption occurring at the interface of TiO₂ and hydrophobic GO. Photocatalytic degradation rates by GO-TiO₂ were compared to those of composites containing nonconductive polymer microparticles (polyethylene, polytetrafluoroethylene). Results showed that polymer-TiO₂ composites performed as well as GO-TiO₂ in degrading both perfluorooctanoic acid and oxalate, a common hole scavenger. Thus, the enhanced activity may occur for any TiO₂-hydrophobic interface, regardless of co-catalyst conductivity. Furthermore, compared to an unmodified reference catalyst, chain length dependence of PFCA degradation by a polymer-TiO₂ composite was found to be less severe, with greater activity toward short-chain species indicating enhanced adsorption behavior. Potential adsorption mechanisms are presented, along with broader implications toward improving the applicability of heterogeneous processes toward a wider range of perfluoroalkyl contaminants.

Effects of surface properties of GaN semiconductors on cell behavior

In recent years, semiconductors have aroused great interest in connecting, observing and influencing the behavior of biological elements, and it is possible to use semiconductor-cell compound interfaces to discover new signal transduction in the biological field. Among them, III-V nitride semiconductors, represented by gallium nitride (GaN), are used as substrates to form semiconductor-biology interfaces with cells, providing a platform for studying the effects of semiconductors on cell behavior. The interfaces between GaN substrate and cells play an important role in detecting and manipulating cell behaviors and provide a new opportunity for studying cell behavior and developing diagnostic systems. Hence, it is necessary to understand how the properties of the GaN substrate directly influence the behavior of biological tissues, and to create editable biological interfaces according to the needs. This paper reviews the synergism between GaN semiconductors and biological cells. The electrical properties, persistent photoconductivity (PPC), nanostructures, and chemical functionalization of GaN on the promotion of cell behaviors, such as growth, adhesion, differentiation, and signal transduction, are emphatically introduced. The purpose of this study is to provide guidance to explore the detection and regulation methods of cell behavior based on semiconductors and promote the application of them in the field of bioelectronics, such as biochips, biosensors, and implantable systems.

A review on degradation of organic dyes by using metal oxide semiconductors

The discharge of organic dye pollutants in natural water bodies has put forward a big challenge of providing clean water to a large part of the population. As the population is increasing with time, only underground water is not sufficient to complete the water requirements of everyone everywhere. Purification of wastewater and its reuse is the only way to fulfill the water needs. Nanotechnology has been used very efficiently for wastewater treatment via photocatalytic degradation of dye molecules. In the past few years, a lot of investigations have been done to enhance the photocatalytic activity of metal oxide semiconductors for water purification. In this review, we have discussed the different methods of synthesis of various metal oxide semiconductor nanoparticles, energy band gap, their role as efficient photocatalysts, radiations used for photocatalytic reactions, and their degradation efficiency to degrade the dye pollutants. We have also discussed the nanocomposites of metal oxide with graphene. These nanocomposites have been utilized as the efficient photocatalyst due to unique characteristics of graphene such as extended range of light absorption, separation of charges, and high capacity of adsorption of the dye pollutants.

Using rice husk ash as a SiO2 source in the preparation of SiO2/Nb2O5 and SiO2/ZnS heterostructures for photocatalytic application

This work presents the synthesis of SiO₂/Nb₂O₅ and SiO₂/ZnS heterostructures using the microwave-assisted hydrothermal (MAH) method, which is fast and has low temperature. The silica used in the synthesis was obtained by burning the rice husk without any pre- or post-treatments. The obtained samples were characterized using various techniques such as X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and UV-visible. The obtained silica was found to be amorphous, and the materials used for modification showed characteristic of the type of synthesis used. SEM images showed that Nb₂O₅ and ZnS interacted with the SiO₂ surface, filling the voids. In the photocatalytic process, the heterostructures showed enhanced decolorization efficiency for dyes such as rhodamine B (RhB) and methylene blue (MB) compared to SiO₂. For RhB, the silica decolorized approximately 24%, and for MB, it discolored approximately 27%; SiO₂/Nb₂O₅ showed 91.24% decolorization efficiency for RhB and 72.77% MB, while SiO₂/ZnS showed approximately 96% for RhB and 100% for MB. All samples were tested under the same conditions. This demonstrates that the use of rice husk residue not only improves the photocatalytic activity of heterostructures but also promotes the utilization of improperly discarded residues.

Overall Photocatalytic CO2 Reduction over Heterogeneous Semiconductor Photocatalysts

The overall photocatalytic CO2 reduction reaction (PCRR), which uses solar energy to convert CO2 and H2O into chemical feedstocks or fuels without sacrificial reagents, plays a momentous role in CO2 utilization and solar energy conversion. However, significant challenges remain in achieving efficient conversion. Researchers have explored various strategies to realize the overall PCRR efficiently. In this review, we first explain the criteria for evaluating the overall PCRR and then summarize the following strategies developed over the past decade to promote it: self-driving material development, Z-scheme heterojunction construction, cocatalyst loading, heteroatom doping, surface vacancy creation, and carrier-material matching. Finally, we discuss essential future research directions in the field. Through this comprehensive review, we aim to provide strategic guidance for the development of efficient overall PCRR systems.

Enhancing decomposition of rhodamine (RhB) and methylene blue (MB) using CdS decorated with Ag or Ru driven by visible radiation

The development of photocatalysts has an influential role in solving the environmental pollution crisis. Herein, the two different noble metals of silver (Ag)/ruthenium (Ru) were separately decorated on cadmium sulfide (CdS) photocatalysts by novel chemical methods. Characterization tests confirmed the formation of Ag/Ru-decorated CdS with spherical morphologies. According to the DRS and PL experiments, Ru-decorated CdS accounted for the highest light absorbance and the most accelerated transfer and detachment of photoelectrons/holes, followed by Ag-decorated CdS compared to pure CdS, which brought proper optical properties of Ag/Ru-decorated CdS. The photodecomposition of methylene blue (MB)/rhodamine B (RhB) as dyes and phenol as a colorless pollutant in the presence of Ag-decorated CdS (96%, 95%, and 69%) and Ru-decorated CdS (100%, 100%, and 80%) exposed to visible light radiation climbed compared to pure CdS (80%, 67%, and 61%) respectively. The influence of various parameters on the MB/RhB photocatalytic activity was investigated. The quenching experiment determined the functions of active species. Finally, experimental results proved that the MB/RhB photodecomposition by Ag/Ru-decorated CdS followed the pseudo-first-order kinetic model.

Effect of applied potential on the optical and electrical properties of Cu2CoO3

The effect of the applied potential on the crystallography, morphology, optical, and electrical properties of copper-cobalt oxide (Cu₂CoO₃) co-electrodeposited on ITO (Indium Tin Oxide) substrate has been studied. The electrochemical behavior of Cu₂CoO₃ using cyclic voltammetry showed that the co-electrodeposition of Cu₂CoO₃ occurred at a negative potential of - 0.70 V versus SCE, following a quasi-reversible reaction controlled by the diffusion process. Chronoamperometry (CA) revealed that the nucleation and growth mechanism of Cu₂CoO₃ follows the instantaneous three-dimensional process according to Scharifker and Hill model. X-ray diffraction (XRD) analysis indicated that the resulting layers at different applied potentials exhibited an orthorhombic structure with a preferred orientation of the crystallites (011) plan. The morphology of the surface changes with potential applied. Furthermore, the optical properties of the copper and cobalt oxide films were investigated using UV-visible spectroscopy; showing that the band gap energy for all the materials increases when the applied potential decreases. The Cu₂CoO₃ layers obtained are p-type semiconductors. The acceptor density (N_A) increases with decreasing applied potential.

Construction of Pd-Co-doped CdS heterojunctions as efficient platforms in photocatalysis

In this work, we present the structural, optical and photocatalytic properties of CdS semiconducting nanostructures, doped with palladium- and cobalt-based species. XRD analysis, corroborated by Raman and XPS, demonstrated the growth of CdS crystallites in the hexagonal structure, whereas solvothermal conversion of neat precursor metal salts resulted in the formation of metallic Pd and cobalt oxide, respectively. Scanning electron microscopy imaging certified the dendritic structure of hybrids, especially in the case where CdS was grown in the presence of either palladium- or cobalt-based nanoparticles. XPS surface analysis revealed that a major fraction of metallic Pd nanoparticles was converted to PdO during the in situ growth of CdS nanoparticles. The oxidation of Pd nanoparticles could be ascribed to chemisorption of oxygen phases onto the metal surface. The presence of cocatalyst nanoparticles resulted in an appreciable shift of the absorption edge of the ternary hybrids by about 50 nm. The optimized hybrid was found to photodegrade Orange G dye almost quantitatively within 2 h, by simulated solar light irradiation. Scavenging experiments revealed that hydroxy radicals were the main transient intermediate, leading to the oxidative degradation of the dye.

Ni(NH3)62+ more efficient than Ni(H2O)62+ and Ni(OH)2 for catalyzing water and phenol oxidation on illuminated Bi2MoO6 with visible light

Nickel (hydr)oxide (NiOH) is known to be good co-catalyst for the photoelectrochemical oxidation of water, and for the photocatalytic oxidation of organics on different semiconductors. Herein we report a greatly improved activity of Bi₂MoO₆ (BMO) by nickel hexammine perchlorate (NiNH). Under visible light, phenol oxidation on BMO was slow. After NiNH, NiOH, and Ni²⁺ loading, a maximum rate of phenol oxidation increased by factors of approximately 16, 8.8, and 4.7, respectively. With a BMO electrode, all catalysts inhibited O₂ reduction, enhanced water (photo-)oxidation, and facilitated the charge transfer at solid-liquid interface, respectively, the degree of which was always NiNH > NiOH > Ni²⁺. Solid emission spectra indicated that all catalysts improved the charge separation of BMO, the degree of which also varied as NiNH > NiOH > Ni²⁺. Furthermore, after a phenol-free aqueous suspension of NiNH/BMO was irradiated, there was a considerable Ni(III) species, but a negligible NH₂ radical. Accordingly, a plausible mechanism is proposed, involving the hole oxidation of Ni(II) into Ni(IV), which is reactive to phenol oxidation, and hence promotes O₂ reduction. Because NH₃ is a stronger ligand than H₂O, the Ni(II) oxidation is easier for Ni(NH₃)⁶⁺ than for Ni(H₂O)⁶⁺. This work shows a simple route how to improve BMO photocatalysis through a co-catalyst.

Synergistic C-TiO2/ZIF-8 type II heterojunction photocatalyst for enhanced photocatalytic degradation of methylene blue

Zinc imidazolate framework (ZIF-8) and titanium dioxide (TiO₂) have been extensively studied as photocatalysts and have shown remarkable potential. In this study, we report the synthesis of a type II heterojunction photocatalyst based on carbon-doped TiO₂ (C-TiO₂) and ZIF-8 as a potentially improved material for solar light-harvested methylene blue (MB) degradation. Pure ZIF-8 has a wide band gap of 4.9 eV, due to which the application of this material to visible light-assisted photocatalytic performance is a challenging task. Therefore, C-TiO₂ has been chosen as a composite material with ZIF-8 owing to its narrow band gap compared to TiO₂. This enables the free radical-initiated photocatalytic reaction to shift into the visible region instead of the ultraviolet region. To construct the C-TiO₂/ZIF-8 heterostructure, the zinc-based ZIF matrix has been built upon the exterior of C-TiO₂ nanoparticles. UV-Vis diffuse reflectance spectroscopy (UV-Vis-DRS) corroborated the decrease in the band gap of ZIF-8 after the fabrication of C-TiO₂/ZIF-8, while X-ray diffraction (XRD) analysis demonstrated a decrease in average d-spacing and average crystallite size of the synthesized photocatalyst. Raman spectra and X-ray photoelectron spectroscopy (XPS) analysis of the synthesized samples were also performed to further understand their chemical structure and elemental content. Ultraviolet photoelectron spectroscopy (UPS) and high-resolution transmission electron microscopy (HRTEM) analyses were performed to understand the valence band (VB) states and the morphology of C-TiO₂/ZIF-8. The comparison between pure ZIF-8 and C-TiO₂/ZIF-8 in the photocatalytic degradation of MB under visible light has also been drawn. A possible charge-transfer mechanism for the same has also been proposed. It is concluded that the synergistic effect of C-TiO₂ and ZIF-8 in C-TiO₂/ZIF-8 produces an effective material for photocatalytic dye degradation.

Sr(Ag1-x Lix )2 Se2 and [Sr3 Se2 ][(Ag1-x Lix )2 Se2 ] Tunable Direct Band Gap Semiconductors

Synthesizing solids in molten fluxes enables the rapid diffusion of soluble species at temperatures lower than in solid-state reactions, leading to crystal formation of kinetically stable compounds. In this study, we demonstrate the effectiveness of mixed hydroxide and halide fluxes in synthesizing complex Sr/Ag/Se in mixed LiOH/LiCl. We have accessed a series of two-dimensional Sr(Ag_1-x Li_x )₂ Se₂ layered phases. With increased LiOH/LiCl ratio or reaction temperature, Li partially substituted Ag to form solid solutions of Sr(Ag_1-x Li_x )₂ Se₂ with x up to 0.45. In addition, a new type of intergrowth compound [Sr₃ Se₂ ][(Ag_1-x Li_x )₂ Se₂ ] was synthesized upon further reaction of Sr(Ag_1-x Li_x )₂ Se₂ with SrSe. Both Sr(Ag_1-x Li_x )₂ Se₂ and [Sr₃ Se₂ ][(Ag_1-x Li_x )₂ Se₂ ] exhibit a direct band gap, which increases with increasing Li substitution (x). Therefore, the band gap of Sr(Ag_1-x Li_x )₂ Se₂ can be precisely tuned via fine-tuning x that is controlled by only the flux ratio and temperature.

Synthesis and Characterization of the Orthorhombic Sn3 O4 Polymorph

An unexplored tin oxide crystal phase (Sn₃ O₄ ) was experimentally synthesized via a facile hydrothermal method. After tuning the often-neglected parameters for the hydrothermal synthesis, namely the degree of filling of the precursor solution and the gas composition in the reactor head space, an unreported X-ray diffraction pattern was discovered. Through various characterization studies, such as Rietveld analysis, energy dispersive X-ray spectroscopy, and first-principles calculations, this novel material was characterized as orthorhombic mixed-valence tin oxide with the composition Sn^II ₂ Sn^IV O₄ . This orthorhombic tin oxide is a new polymorph of Sn₃ O₄ , which differs from the reported conventional monoclinic structure. Computational and experimental analyses showed that orthorhombic Sn₃ O₄ has a smaller band gap (2.0 eV), enabling greater absorption of visible light. This study is expected to improve the accuracy of hydrothermal synthesis and aid the discovery of new oxide materials.

High Electron Mobility Hot-Exciton Induced Delayed Fluorescent Organic Semiconductors

The development of high mobility emissive organic semiconductors is of great significance for the fabrication of miniaturized optoelectronic devices, such as organic light emitting transistors. However, great challenge exists in designing key materials, especially those who integrates triplet exciton utilization ability. Herein, dinaphthylanthracene diimides (DNADIs), with 2,6-extended anthracene donor, and 3'- or 4'-substituted naphthalene monoimide acceptors were designed and synthesized. By introducing acceptor-donor-acceptor structure, both materials show high electron mobility. Moreover, by fine-tuning of substitution sites, good integration with high solid state photoluminescence quantum yield of 26 %, high electron mobility of 0.02 cm²  V^-1  s^-1 , and the feature of hot-exciton induced delayed fluorescence were obtained in 4'-DNADI. This work opens a new avenue for developing high electron mobility emissive organic semiconductors with efficient utilization of triplet excitons.

Room Temperature Incorporation of Arsenic Atoms into the Germanium (001) Surface

Germanium has emerged as an exceptionally promising material for spintronics and quantum information applications, with significant fundamental advantages over silicon. However, efforts to create atomic-scale devices using donor atoms as qubits have largely focused on phosphorus in silicon. Positioning phosphorus in silicon with atomic-scale precision requires a thermal incorporation anneal, but the low success rate for this step has been shown to be a fundamental limitation prohibiting the scale-up to large-scale devices. Here, we present a comprehensive study of arsine (AsH₃ ) on the germanium (001) surface. We show that, unlike any previously studied dopant precursor on silicon or germanium, arsenic atoms fully incorporate into substitutional surface lattice sites at room temperature. Our results pave the way for the next generation of atomic-scale donor devices combining the superior electronic properties of germanium with the enhanced properties of arsine/germanium chemistry that promises scale-up to large numbers of deterministically placed qubits.

Mixed valence Ce-doped TiO2 with multiple energy levels and efficient charge transfer for boosted SERS performance

Considering the variable valence characteristics of rare earth elements, they can be in a variety of valence forms coexistence. Doping of rare earth element with different valence states may produce different energy levels to tune the semiconductor energy band structure. We utilize rare earth element Ce doping TiO₂ for the development of high-performance semiconductor surface-enhanced Raman scattering (SERS) substrates based on an energy-level tuning strategy. Ce doping not only forms multiple energy levels including Ce³⁺ and Ce⁴⁺ metal doping energy levels in the bandgap of TiO₂, but also enriches the surface state level of TiO₂ itself, which together promote the separation of photogenerated carriers and improve charge transfer efficiency between substrates and absorbed molecules. This endows TiO₂ semiconductor substrate with a higher SERS enhancement factor, which can reach 2.2 × 10⁶. The detectable concentration of methylene blue can be as low as 10^-10 mol/L. Moreover, the semiconductor substrate exhibits excellent uniformity and stability. This study not only provides a new strategy to develop excellent semiconductor SERS substrate with multiple energy levels, but also lays the foundation for promising practical application of semiconductor substrate.

Removal of harmful algae in natural water by semiconductor photocatalysis- A critical review

Harmful Algal Blooms (HABs) have turned out to be a global occurrence owing to the detrimental phenomenon like eutrophication and global climate change caused by human activities. This newly emergent threat imposes a severe hazardous to public health, ecosystems and fishery-based economies. Rapid and exponential growth of certain delirious and toxic algal species shall be held causative to the formation of HABs. The potential disadvantages they pose, make it necessary the identification of efficient treatment methodologies. Photocatalysis has been identified as the most promising solution amongst all the identified and investigated methods, for the environmental and economic benefits beheld. Different treatment methodologies were evaluated and light has been thrown on the advantages beheld by photocatalysis over the other methods. Focus has been given to the different photocatalysts that have been so far put to use towards photocatalytic disinfection of HABs and algal toxins. This present study provides useful information on the application of the traditional and photocatalysis process for removal of HABs in water bodies. Moreover, the results revealed that photocatalysis method could cause potent inhibitory effect on growth of algae species and disrupted algal cells membranes to some extent. Finally, the conventional treatment techniques have been recognized to be insufficient for removal of HABs. However, the photocatalyst technology have been utilized mostly for the mineralization and neutralization of the algal pollutants without any harmful secondary pollutants.

Electronic, non-linear optical, optoelectronic, and thermodynamic properties of undoped and doped bis (ethylenedithio) tetraselenafulvalene (BETS) (C10H8S4Se4) molecule: first study using ab initio investigation

We have performed the ab initio calculation of the undoped and doped molecules bis (ethylenedithio) tetraselenafulvalene (BETS). Carbone (C) atoms have been substituted by Boron (B) to investigate their effects on the electronic structure and nonlinear optical, optoelectronic, and thermodynamic properties of BETS molecule. The RHF and hybrid density functional theories (WB97XD, B3PW91, and B3LYP) methods were applied, using the cc-pVDZ basis set. We found that the energy gap (Egap) of the doped molecules are respectively 2.476 eV and 2.569 eV for C₈B₂H₈S₄Se₄ and C₇B₃H₈S₄Se₄ with B3LYP/cc-pVDZ basis set, lower than one of the undoped molecule (3.316 eV). The significant increase values of polarizability (˂α˃) and first order hyperpolarizability (β) of the doped compounds, especially in C₈B₂H₈S₄Se₄ (< α >  = 4.5315 × 10^-23 esu, β = 22,672.27 × 10^-33 esu and < α >  = 4.518 × 10^-23 esu, β = 23,657.43 × 10^-33 esu respectively for B3LYP and B3PW91) compared to those of the undoped molecule (< α >  = 4.3602 × 10^-23 esu, β = 1290.38 × 10^-33 esu, and < α >  = 4.518 × 10^-23 esu) show that the new molecules have a good nonlinear optical property. Results suggest that these molecules doped with boron are a potential candidate as semiconductors compounds and nonlinear optical materials.

High mobility and ON/OFF ratio of solution-processable p-channel OFETs from arylacetylene end-capped alkoxyphenanthrenes

New arylacetylene end-capped alkoxyphenanthrenes were synthesized and demonstrated as the best active layer for solution-processable p -channel organic field-effect transistors. The alkoxy chain embedded compounds exhibited enhanced solubility and induced non-covalent interactions resulting in effective molecular packing. The 'Lewis soft' heteroatoms direct the most stable conformation with dihedral angles possible for molecular interactions, and energy levels. DFT studies supported the finetuning of FMOs, with high HOMO levels ~-5.2 eV ensuring a low barrier for charge injection. OFET devices exhibited a maximum charge carrier mobility up to 1.30 cm 2 /Vs with the highest ON/OFF ratio of 10 7 . The strong π-π interactions and the crystallinity of the films are well supported by GIXRD and SEM analysis.

Multi-element Simultaneous sensitization of solution cathode glow discharge atomic emission spectrometry by using portable semiconductor anode refrigeration

In this study, a modified solution cathode glow discharge atomic emission spectrometry (SCGD-AES) was used to detect metal elements in electroplating sewage. The SCGD-AES device was equipped with a portable semiconductor anode refrigeration unit, which was built independently. The red-heat effect of tungsten electrode was alleviated by adding the portable refrigeration unit, thus improving thermal stability with the withstand voltage from 1040 V to 1140 V. Compared with the devices without semiconductor refrigeration, the chromium was excited more favorable when the discharge voltage increased, and the limit of detection (LOD) decreased by 8.5 times. Furthermore, the LODs of Zn, Cd, Ni, Cu and Pb decreased by 1.8-3.2 times, respectively, which realized the detection of elements in electroplating sewage and showed high performance in the field of trace elements analysis. Furthermore, the accuracy of the method was verified by stream sediment reference material (GBW07312), and the results were consistent with the certified values. The recoveries of elements added to industrial sewage and seawater range were from 90.5 to 98.7%, demonstrating good accuracy of the proposed method.

Graphene-based photocatalytic nanocomposites used to treat pharmaceutical and personal care product wastewater: A review

Photocatalytic technology has been widely studied by researchers in the field of environmental purification. This technology can not only completely convert organic pollutants into small molecules of CO₂ and H₂O through redox reactions but also remove metal ions and other inorganic substances from water. This article reviews the research progress of graphene-based photocatalytic nanocomposites in the treatment of wastewater. First, we elucidate the basic principles of photocatalysis, the types of graphene-based nanocomposites, and the role of graphene in photocatalysis (e.g., graphene can accelerate the separation of photon-hole pairs and increase the intensity and range of light absorption). Second, the preparation, characterization, and application of composites in wastewater are introduced. We also discuss the kinetic model of the photocatalytic degradation of pollutants. Finally, the enhancement mechanism of graphene in terms of photocatalysis is not completely clear, and graphene-based photocatalysts with high catalytic efficiency, low cost, and large-scale production have not yet appeared, so there is an urgent need for more extensive and in-depth research.

Tungsten oxide polymorphs and their multifunctional applications

Owing to the natural abundance, easy availability, high stability, non-stoichiometry, and chemical diversity, considerable interest has been devoted to tungsten oxide (WO_3-x) nanomaterials, and many advances have been achieved ranging from traditional catalysts and electronics to emerging artificial intelligence. This review focuses on recent progress of WO_3-x polymorphs and their multifunctional applications. The structural diversity and crystal phase transitions of WO_3-x and recent advances on the general synthesis of various WO_3-x nanostructures are first summarized, since the crystal structure and morphology adjustment obviously affect the physiochemical merits of WO_3-x materials. Then, their applications and related mechanisms in different fields are demonstrated, such as gas sensing, chromogenic (electro-, photo-, gaso-, and thermochromic), photocatalytic (pollutant degradation and water splitting), and emerging applications (biomedical, antibiotic, and artificial intelligence). With the advances highlighted here and the ongoing research efforts, the continuous breakthrough in functionalized WO_3-x nanostructure and their attractive applications is foreseeable in the future.

Photocatalytic and biological technologies for elimination of microplastics in water: Current status

Water pollution by microplastics (MPs) has emerged as a significant environmental and public health concern. Several conventional technologies in drinking water and wastewater treatment facilities are capable of capturing a substantial portion of microplastics from surface water; however, only limited methods are available for actual destruction of microplastics. Rate of success is highly variable, and actual mechanisms which result in MP destruction are only partly known. Photocatalysis and microbial degradation technologies show promise at laboratory scale for the transformation of microplastics to water-soluble hydrocarbons, carbon dioxide and, in limited cases, useful fuels. Both photocatalytic and microbial technologies offer the potential for long-term water security and ecological stability and deserve further attention by scientists. Additional research is necessary, however, in identifying more effective semiconductors for photocatalysis, and optimal effective microbial consortia and environmental conditions to optimize microplastic biodegradation. Many more polymer types beyond polyethylene must be studied for degradation, and laboratory-scale research must be expanded to field-scale. This paper provides a comprehensive overview of processes and mechanisms for removing MPs by photocatalysis and microbial technologies. It provides useful data for research dedicated to improved removal of MPs from surface waters.

Study of charge transfer effect in Surface-Enhanced Raman scattering (SERS) by using Antimony-doped tin oxide (ATO) nanoparticles as substrates with tunable optical band gaps and free charge carrier densities

Surface-enhanced Raman scattering (SERS) has been applied in many fields, but still has the limitation of widespread applications on semiconductor substrates. In this work, a series of antimony-doped tin oxide (ATO) nanoparticles (NPs) have been synthesized by a hydrothermal method and were used as SERS substrates for the first time. Interestingly, a charge transfer (CT) effect was revealed between the probing molecules of 4-mercaptobenzoic acid (4-MBA) and the substrates of ATO NPs, which accounts for the SERS enhancement and shows dependence to the Sb ions doping ratios in ATO NPs. By considering the energy level diagram of the ATO-MBA complexes and the doping theory of semiconductors, this phenomenon is believed to connect to the variance of the optical band gap energy (E_g), which is accompanied with the changes of free charge carrier densities in conduction bands (CBs) of ATO NPs due to different doping contents. The study of the E_g- or free-charge-carrier-density-dependent property of the semiconductor-based SERS provides a new point of view for the development of new semiconductor SERS substrates and also contributes to the SERS CT mechanism.

Complete ablation of tumors using synchronous chemoradiation with bimetallic theranostic nanoparticles

Synchronous chemotherapy and radiotherapy, termed chemoradiation therapy, is now an important standard regime for synergistic cancer treatment. For such treatment, nanoparticles can serve as improved carriers of chemotherapeutics into tumors and as better radiosensitizers for localized radiotherapy. Herein, we designed a Schottky-type theranostic heterostructure, Bi2S3-Au, with deep level defects (DLDs) in Bi2S3 as a nano-radiosensitizer and CT imaging contrast agent which can generate reactive free radicals to initiate DNA damage within tumor cells under X-ray irradiation. Methotrexate (MTX) was conjugated onto the Bi2S3-Au nanoparticles as a chemotherapeutic agent showing enzymatic stimuli-responsive release behavior. The designed hybrid system also contained curcumin (CUR), which cannot only serve as a nutritional supplement for chemotherapy, but also can play an important role in the radioprotection of normal cells. Impressively, this combined one-dose chemoradiation therapeutic injection of co-drug loaded bimetallic multifunctional theranostic nanoparticles with a one-time clinical X-ray irradiation, completely eradicated tumors in mice after approximately 20 days after irradiation showing extremely effective anticancer efficacy which should be further studied for numerous anti-cancer applications.

Au nanoparticles decorated ZnO/ZnFe2O4 composite SERS-active substrate for melamine detection

Surface-enhanced Raman scattering (SERS) based on plasmonic metal nanoparticles and semiconductors has been used as performance-enhancing structures for sensing trace chemicals. We have selected a case of oxide functional oxide organic nanostructure between ZnFe₂O₄ and ZnO, denoted as ZZF. By decorating such nanostructure with AuNPs, to identify R6G in varying concentrations (10^-6 M - 10^-12 M), an enhancement factor of 1.6 × 10⁸ was observed. The material was used for the identification of melamine in the concentration range of 0.39 μM-7.92 μM. This high-performance nanocomposite provides improved melamine sensitivity towards SERS and the limit of detection as low as 0.39 μM. The Au-ZZF SERS substrate can yield a SERS enhancement factor of 1.37 × 10⁷. The experimental performance demonstrates that excellent SERS enhancement is due to electrons movement within ZZF and Au nanoparticles. Owing to its easy and effective synthesis methodology, this sensitive and specific SERS substrate is a promising technique to detect trace chemicals. We further study the best energetically favorable orientation of melamine molecules over the substrate leading to the SERS activity using density functional theoretical study.

Boron Carbon Oxynitride as a Novel Metal-Free Photocatalyst

Boron-based nanomaterials are emerging as non-toxic, earth-abundant (photo)electrocatalyst materials in solar energy conversion for the production of solar hydrogen fuel and environmental remediation. Boron carbon oxynitride (BCNO) is a quaternary semiconductor with electronic, optical, and physicochemical properties that can be tuned by varying the composition of boron, nitrogen, carbon, and oxygen. However, the relationship between BCNO's structure and -photocatalytic activity relationship has yet to be explored. We performed an in-depth spectroscopic analysis to elucidate the effect of using two different nitrogen precursors and the effect of annealing temperatures in the preparation of BCNO. BCNO nanodisks (D = 6.7 ± 1.1 nm) with turbostratic boron nitride diffraction patterns were prepared using guanidine hydrochloride as the nitrogen source precursor upon thermal annealing at 800°C. The X-ray photoelectron spectroscopy (XPS) surface elemental analysis of the BCNO nanodisks revealed the B, C, N, and O compositions to be 40.6%, 7.95%, 37.7%, and 13.8%, respectively. According to the solid-state 11B NMR analyses, the guanidine hydrochloride-derived BCNO nanodisks showed the formation of various tricoordinate BNx(OH)3-x species, which also served as one of the photocatalytic active sites. The XRD and in-depth spectroscopic analyses corroborated the preparation of BCNO-doped hexagonal boron nitride nanodisks. In contrast, the BCNO annealed at 600 °C using melamine as the nitrogen precursor consisted of layered nanosheets composed of B, C, N, and O atoms covalently bonded in a honeycomb lattice as evidence by the XRD, XPS, and solid-state NMR analysis (11B and 13C) analyses. The XPS surface elemental composition of the melamine-derived BCNO layered structures consisted of a high carbon composition (75.1%) with a relatively low boron (5.24%) and nitrogen (7.27%) composition, which indicated the formation of BCNO-doped graphene oxides layered sheet structures. This series of melamine-derived BCNO-doped graphene oxide layered structures were found to exhibit the highest photocatalytic activity, exceeding the photocatalytic activity of graphitic carbon nitride. In this layered structure, the formation of the tetracoordinate BNx(OH)3-x(CO) species and the rich graphitic domains were proposed to play an important role in the photocatalytic activity of the BCNO-doped graphene oxides layered structures. The optical band gap energies were measured to be 5.7 eV and 4.2 eV for BCNO-doped hexagonal boron nitride nanodisks and BCNO-doped graphene oxides layered structures, respectively. Finally, BCNO exhibited an ultralong photoluminescence with an average decay lifetime of 1.58, 2.10, 5.18, and 8.14 µs for BGH01, BGH03, BMH01, BMH03, respectively. This study provides a novel metal-free photocatalytic system and provides the first structural analysis regarding the origin of BCNO-based photocatalyst.

High-efficiency charge transfer on SERS-active semiconducting K2Ti6O13 nanowires enables direct transition of photoinduced electrons to protein redox centers

Photoinduced charge transfer (PICT) plays a crucial role in the chemical mechanism of surface-enhanced Raman scattering (SERS), in which small organic molecules are generally used as probes. Herein, semiconducting K₂Ti₆O₁₃ nanowires (NWs) are synthesized and are found to exhibit high SERS activity probed by 4-mercaptobenzoic acid (4-MBA). Density functional theory (DFT) calculations reveal high-efficiency CT on the K₂Ti₆O₁₃ nanowires. Furthermore, PICT on the K₂Ti₆O₁₃ NWs is for the first time evidenced by a redox protein, cytochrome c (Cyt c). Under optimized experimental conditions, the transformation of oxidized Cyt c to its reduced state clearly verifies the electron transfer (ET) from the K₂Ti₆O₁₃ nanowire to the protein. The ET mechanism is explored based on energy levels of semiconductors and molecular dynamics simulations, thus revealing the importance of energy level matching and electron tunneling from the semiconductor surface to the redox center. This study indicates a great potential of multiple-layered K₂Ti₆O₁₃ NWs in the application of SERS on semiconducting materials and more importantly, it provides a new route for the rational design of protein-semiconductor interfaces for investigating electron transfer processes of redox proteins and biocatalytic reactions.

Fast organic degradation on Ti- and Bi-based photocatalysts via co-deposited Pt and Ni3(PO4)2 nanoparticles

Environmental remediation via semiconductor (SC) photocatalysis has attracted great attention over the past three decades. However, prospect for large scale application is still under debate, basically due to the bottleneck of fast charge recombination and/or slow surface reaction. Herein we report a universal solution of speeding up organic degradation simply via co-deposited Pt and nickel phosphate (NiP). Several representative SCs have been examined, including TiO₂ (anatase, rutile, and brookite) under a 320 nm light, and Bi-based SC (BiVO₄, Bi₂WO₆, and Bi₂MoO₆) under a 420 nm light. In all cases, the rates of phenol degradation in aqueous solution always varied not only in the order of NiP/Pt/SC > Pt/SC > NiP/SC > SC, but also NiP/Pt/SC > (Pt/SC + NiP/SC + SC). Meanwhile, hydroquinone and benzoquinone were produced as the main intermediates, but their concentration was much lower than that of phenol decreased, especially for NiP-containing sample. The solid was characterized with several techniques, including photoluminescence and (photo)electrochemical measurement. It is proposed that Pt and NiP act as co-catalysts for O₂ reduction and phenol oxidation, respectively. Such electron and hole transfer promote each other, additionally improving the efficiency of charge separation, and further increasing the rates of surface reactions. This work highlights the necessity of a versatile co-catalyst in SC photocatalysis.

A comparison of meta-analysis results with and without adjustment for the healthy worker effect: cancer mortality among workers in the semiconductor industry

OBJECTIVES

This study compared the results of meta-analysis with and without adjustment for the healthy worker effect on the association between working in the semiconductor industry and cancer mortality.

METHODS

Six studies that reported standardized mortality ratios (SMRs) for cancers were selected for meta-analysis. Using a random-effects model, the SMR results from each study were combined for all cancers and leukemias to estimate the summary SMRs (95% confidence interval, CI). To adjust for the healthy worker effect, the relative standardized mortality ratio (rSMR=SMRx/SMRnot x) were calculated using observed and expected counts for the specific cause of interest (i.e., all cancers and leukemias) and the observed and expected counts for all other causes of mortality. Then, the rSMR results were combined to estimate the summary rSMRs (95% CIs).

RESULTS

The SMRs for all causes of mortality among semiconductor industry workers ranged from 0.25 to 0.80, which reflects a significant healthy worker effect. A remarkable difference was found between the summary SMRs and the summary rSMRs. The summary SMR for all cancers was 0.70 (95% CI, 0.63 to 0.79) whereas the summary rSMR was 1.38 (95% CI, 1.20 to 1.59). The summary SMR for leukemia was 0.88 (95% CI, 0.72 to 1.07), and the summary rSMR was 1.88 (95% CI, 1.20 to 2.95).

CONCLUSIONS

Our results suggest that adjustment for the healthy worker effect (i.e., rSMR) may be useful in meta-analyses of cohort studies reporting SMRs.

Possibility of Benzene Exposure in Workers of a Semiconductor Industry Based on the Patent Resources, 1990-2010

BACKGROUND

This study aimed to assess the possibility of benzene exposure in workers of a Korean semiconductor manufacturing company by reviewing the issued patents.

METHODS

A systematic patent search was conducted with the Google "Advanced Patent Search" engine using the keywords "semiconductor" and "benzene" combined with all of the words accessed on January 24, 2016.

RESULTS

As a result of the search, we reviewed 75 patent documents filed by a Korean semiconductor manufacturing company from 1994 to 2010. From 22 patents, we found that benzene could have been used as one of the carbon sources in chemical vapor deposition for capacitor; as diamond-like carbon for solar cell, graphene formation, or etching for transition metal thin film; and as a solvent for dielectric film, silicon oxide layer, nanomaterials, photoresist, rise for immersion lithography, electrophotography, and quantum dot ink.

CONCLUSION

Considering the date of patent filing, it is possible that workers in the chemical vapor deposition, immersion lithography, and graphene formation processes could be exposed to benzene from 1996 to 2010.

Toxicity of CuS/CdS semiconductor nanocomposites to liver cells and mice liver

Semiconductor nanomaterials not only bring great convenience to peoples lives but also become a potential hazard to human health. The purpose of this study was to evaluate the toxicity of CuS/CdS nanocomposites in hepatocytes and mice liver. The CuS/CdS semiconductor nanocomposites were synthesized by a biomimetic synthesis - ion exchange strategy. Nanosize was confirmed by high-resolution transmission electron microscopy and dynamic light scattering. The composition and physical properties were measured by powder X-ray diffraction, Fourier transform infrared spectra, atomic absorption spectroscopy, thermogravimetry-differential scanning calorimetry and zeta potential analysis. The results revealed that CuS/CdS nanocomposites had 8.7 nm diameter and negative potential. Ion exchange time could adjust the ratio of CuS and CdS in nanocomposites. The toxicological study revealed that CuS/CdS nanocomposites could be internalized into liver cells, inhibited endogenous defense system (e.g. GSH and SOD), induced the accumulation of oxidation products (e.g. ROS, GSSG and MDA), and caused hepatocyte apoptosis. The in vivo experiments in Balb/c mice showed that the experimental dose (4 mg/kg) didn't cause observable changes in mice behavior, physical activity and pathological characteristics, but the continuous accumulation of Cd²⁺ in the liver and kidney might be responsible for its long-term toxicity.

Recent progress in green and biopolymer based photocatalysts for the abatement of aquatic pollutants

Enormous research studies on the abatement of anthropogenic aquatic pollutants including organic dyes, pesticides, cosmetics, antibiotics and inorganic species by using varieties of semiconductor photocatalysts have been reported in recent decades. Besides, many of these photocatalysts suffer in real applications owing to their high production cost and low stability. In many cases, the photocatalysts themselves are being considered as secondary pollutants. To eliminate these drawbacks, the green synthesized photocatalysts and the use of biopolymers as photocatalyst supports are considered in recent years. In this context, recent developments in green synthesized metals, metal oxides, other metal compounds, and carbon based photocatalysts in water purification are critically reviewed. Furthermore, the pivotal role of biopolymers including chitin, chitosan, cellulose, natural gum, hydroxyapatite, alginate in photocatalytic removal of aquatic pollutants is comprehensively reviewed. The presence of functional groups, electron trapping ability, biocompatibility, natural occurrence, and low production cost are the major reasons for using biopolymers in photocatalysis. Finally, the summary and conclusion are presented along with existing challenges in this research area.