Search Results (79)

A novel nanomaterial photoelectrochemical aptamer sensor based on CdS@NiMoS heterojunction nanocomposites was constructed for highly sensitive detection of chloramphenicol (CAP) in antibiotic residues. Through optimization of the material synthesis process, the optimal doping ratio of MoS₂ to Ni³⁺ (70% MoS₂ and 10% Ni³⁺) was identified, which significantly enhanced the photogenerated carrier separation efficiency. In thin-film preparation, comparative analysis of four film-forming methods led to the determination of an optimal process with stability. To achieve highly specific CAP detection, the nanocomposite chip was integrated with nucleic acid aptamer biorecognition elements within a standard three-electrode detection system. Experimental results demonstrated a linear response (R² = 0.998) in the 0.1–2 μM concentration range, with a detection limit of 3.69 nM (3σ/S). Full article

Organophosphorus pesticides (OPs), while pivotal for agricultural productivity, pose severe environmental and health risks due to their persistence and bioaccumulation. Existing detection methods, such as chromatography and spectroscopy, face limitations in field adaptability, cost, and operational complexity. To address these challenges, this study introduces a novel dual-mode photoelectrochemical–electrochemical (PEC-EC) sensor based on a Co,N-TiO₂@ZrO₂/3DGH nanocomposite. The sensor synergistically integrates zirconium oxide (ZrO₂) for selective OP capture via phosphate-Zr coordination, cobalt-nitrogen co-doped titanium dioxide (Co,N-TiO₂) for visible-light responsiveness, and a three-dimensional graphene hydrogel (3DGH) for enhanced conductivity. In the PEC mode under light irradiation, OP adsorption induces charge recombination, yielding a logarithmic photocurrent attenuation with a detection limit of 0.058 ng mL⁻¹. Subsequently, the EC mode via square wave voltammetry (SWV) self-validates the results, achieving a detection limit of 0.716 ng mL⁻¹. The dual-mode system demonstrates exceptional reproducibility, long-term stability, and selectivity against common interferents. Parallel measurements revealed <5% inter-mode discrepancy, validating the intrinsic self-checking capability. This portable platform bridges the gap between laboratory-grade accuracy and field-deployable simplicity, offering transformative potential for environmental monitoring and food safety management. Full article

Photoelectrochemical (PEC) sensors have emerged as potential analysis techniques in recent years due to PEC’s benefits, which include straightforward operation, quick response times, and basic equipment. In this work, a new PEC sandwich immunoassay was fabricated, which was based on low-toxicity BiOI/BiOCl composites accompanied by enhanced signal detection via AgI-conjugated antibodies (Ab₂-AgI). Specifically, the low-toxicity inorganic semiconductor BiOI/BiOCl composites were first utilized in PEC bioanalysis. Owing to the unique configuration of energy levels between BiOI and BiOCl, the photoelectric response was more excellent than those of BiOI or BiOCl alone. Moreover, the Ab₂-AgI conjugates were utilized as signal amplification components through the specific antibody–antigen immunoreaction. In the presence of target Ag, the immobilized Ab₂-AgI conjugates clearly improve the steric hindrance of the sensing electrode and effectively hinder the transfer of photo-induced holes; meanwhile, AgI NPs can competitively absorb excitation light. A new PEC immunosensing platform for detecting tumor markers at 0 V under visible light excitation was developed, and using carcinoembryonic antigen (CEA) as a model analyte demonstrated an ultra-low detection limit of 4.9 fg·mL⁻¹. Meanwhile, it demonstrated excellent specificity and stability, potentially opening up a novel and promising platform for detecting other critical biomarkers. Full article

Two-dimensional (2D) Xenes, including graphene where X represents C, Si, Ge, and Te, represent a groundbreaking class of materials renowned for their extraordinary electrical transport properties, robust photoresponse, and Quantum Spin Hall effects. With the growing interest in 2D materials, research on germanene-based systems remains relatively underexplored despite their potential for tailored optoelectronic functionalities. Herein, we demonstrate a facile and rapid chemical synthesis of tellurium-doped germanene hydride (Te-GeH) nanostructures (NSs), achieving precise atomic-scale control. The 2D Te-GeH NSs exhibit a broadband optical absorption spanning ultraviolet (UV) to visible light (VIS), which is a critical feature for multifunctional photodetection. Leveraging this property, we engineer photoelectrochemical (PEC) photodetectors via a simple drop-casting technique. The devices deliver excellent performance, including a high responsivity of 708.5 µA/W, ultrafast response speeds (92 ms rise, 526 ms decay), and a wide operational bandwidth. Remarkably, the detectors operate efficiently at zero-bias voltage, outperforming most existing 2D-material-based PEC systems, and function as self-powered broadband photodetectors. This work not only advances the understanding of germanene derivatives but also unlocks their potential for next-generation optoelectronics, such as energy-efficient sensors and adaptive optical networks. Full article

This study investigates the photoelectrochemical (PEC) performance of molybdenum-doped bismuth vanadate (Mo-doped BiVO₄) and its heterojunction with the BiOCl layer in glucose and urea sensing. Photoelectrochemical analyses, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), revealed that the formation of a heterojunction enhanced charge carrier separation. The impact of the interaction between the surface of the photoanode and analytes on sensing performance was systematically evaluated. Among the tested configurations, Mo-doped BiVO₄ exhibited superior glucose sensing with a limit of detection (LOD) of 0.173 µM, while BiVO₄/BiOCl demonstrated an LOD of 2.474 µM. In the context of urea sensing, Mo-doped BiVO₄ demonstrated an LOD of 0.656 µM, while BiVO₄/BiOCl exhibited an LOD of 0.918 µM. Notably, despite the enhanced PEC activity observed in heterostructured samples, Mo-doped BiVO₄ exhibited superior sensing performance, attributable to good interaction with analytes. The photocurrent response trends—an increase with glucose concentration and a decrease with urea concentration—were attributed to oxidation and adsorption phenomena on the photoanode surface. These findings underscore the critical role of photoanode surface engineering in advancing PEC sensor technology, paving the way for more efficient environmental and biomedical applications. Full article

A novel photoelectrochemical (PEC) biosensor was proposed by preparing Au NP/MXene–BiOCl Moiré superlattice nanosheets as the probes. Upon irradiation with visible light, the probe exhibited excellent electrical conductivity as well as high photoelectric conversion efficiency. Benefitting from the excellent PEC property of the hybrid probe, sensitive and accurate detection of protein kinase activity was demonstrated with a limit of detection of 0.0029 U mL⁻¹. This study verifies the great PEC potential of MXene hybrid nanomaterials. Full article

This study presents a novel method combining photoelectrochemical etching with ultrasonic vibration for the formation of nanocrystalline porous silicon (NC-PS). This combined process enhances the band gap energy absorption (BEA) by reducing bubble accumulation in the etching area. It is found that laser irradiation can decrease the etching rate, while ultrasonic vibration aids with bubble expulsion, preventing accumulation in the etching area, resulting in more uniform etching and increasing the porosity of the porous silicon (PS). High porosity in NC-PS structures enhances the surface area, thereby increasing electron mobility and improving the electron energy distribution. Our experiments demonstrate that this combined process leads to more uniform and deeper etching and the creation of well-defined porous structures. The more uniform PS size distribution (8–14 nm) achieved by photoelectrochemical etching combined with ultrasonic vibration enhances the optical properties of the material due to quantum confinement effects. Porosity measurements provide essential surface characterization information that is crucial for determining the performance of PS diode components in various applications. Our findings demonstrate that this combination technique improves the uniformity, efficiency, and precision of porous silicon etching, producing material for high-performance applications, including sensors, catalysts, and photonic devices. Full article

Anatase-phase rod-shaped TiO₂ nanocrystals are prepared by the solvothermal method, the surface is metalated, and doped nanocrystals are achieved by thermal diffusion of surface metal ions. Incorporation of dopant ions into TiO₂ lattice enhances the visible light absorption of the material and in some cases can increase the rate of photocatalysis. Even though there are overflowing studies on the preparation of doped TiO₂ materials, there are no methods that enable the precise control of dopant concentration in TiO₂ nanocrystals. We have developed a method to load the surface of oleic acid stabilized anatase-phase rod-shaped TiO₂ nanocrystals (approx. 3 ± 1 nm diameter and 40 ± 10 nm long) with transition metal ions followed by ion diffusion to prepare metal-doped nanocrystals with exact control of the dopant concentration. Specifically, in this work, Cr³⁺ adsorbs TiO₂ nanorods to yield a green colloid, followed by ion diffusion at elevated temperature. After removal of any remaining surface Cr³⁺, tan-colored chromium-doped TiO₂ nanorods can be obtained. Electron microscopy and powder X-ray diffraction indicate no change in nanocrystal size and morphology throughout the process. The TiO₂ nanorods play an important role in photocatalysis owing to their excellent chemical and physical properties. Titanium dioxide is a low-cost, non-toxic, highly stable, chemically robust material. Doped TiO₂ materials have found application in photocatalysis (oxidative degradation of organic molecules, hydrogen evolution), photovoltaics, solar cells, lithium-ion batteries, supercapacitors, and sensors. TiO₂ photocatalysis is also the basis for clean energy technologies, such as dye-sensitized solar cells and photoelectrochemical cells. In photocatalysis applications, nanocrystalline TiO₂ presents advantages of a high surface area, ability to control the surface facet, and minimized bulk recombination. Full article

Microelectrode-based photoelectrochemical (PEC) technology is a novel and rapidly developing analytical method for the in vivo probing of neurochemical events in the brain, which is distinguished by its low background noise and high detection sensitivity. This mini-review focuses on recent advances in in vivo PEC biosensors. We classify the key characteristics of PEC technology and elucidate its underlying principles. Furthermore, newly developed PEC neurochemical sensing methods for detecting various substances, including SO₂, antibiotics, metal ions, neurotransmitters, and thioalcohols, as well as cells are discussed. Finally, this review concludes with a comprehensive summary and perspectives on the emerging opportunities and challenges facing this field. Full article

This study presents the findings of an investigation into the characteristics and capabilities of BiVO₄ and Mo-doped BiVO₄ coatings for the detection of diclofenac (DCF). In this study, a neutral sodium sulfate electrolyte and an alkaline sodium borate buffer were selected, and a range of potentials were employed to ascertain the impact of diverse conditions on the sensing performance of diclofenac. The introduction of Mo-doping had a profound impact on the photoelectrochemical response of the BiVO₄ coating. However, it was observed that Mo-doping resulted in an increase in the adsorption of diclofenac oxidation products on the surface of the photoanode, which in turn led to a negative blocking effect. To evaluate the structural and morphological properties of the coatings, X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and energy dispersive analysis (EDX) were conducted. The photoelectrochemical properties were evaluated through the use of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA). An increase in the photocurrent density of BiVO₄ was observed in response to an increase in the concentration of diclofenac within a range of 0.1 to 1 mg L⁻¹ during the sensing experiments. However, at higher concentrations, saturation of diclofenac was observed at the photoelectrode/electrolyte interface. The results of selectivity experiments demonstrated that the nature of the electrolyte has a significant impact on the selectivity of designed photoelectrochemical sensors. Full article

Sweat is considered the most promising candidate to replace conventional blood samples for noninvasive sensing. There are many tools and optical and electrochemical methods that can be used for detecting sweat biomarkers. Electrochemical methods are known for their simplicity and cost-effectiveness. However, they need to be optimized in terms of selectivity and catalytic activity. Therefore, electrode modifiers such as nanostructures and metal–organic frameworks (MOFs) or combinations of them were examined for boosting the performance of the electrochemical sensors. The MOF structures can be prepared by hydrothermal/solvothermal, sonochemical, microwave synthesis, mechanochemical, and electrochemical methods. Additionally, MOF nanostructures can be prepared by controlling the synthesis conditions or mixing bulk MOFs with nanoparticles (NPs). In this review, we spotlight the previously examined MOF-based nanostructures as well as promising ones for the electrochemical determination of sweat biomarkers. The presence of NPs strongly improves the electrical conductivity of MOF structures, which are known for their poor conductivity. Specifically, Cu-MOF and Co-MOF nanostructures were used for detecting sweat biomarkers with the lowest detection limits. Different electrochemical methods, such as amperometric, voltammetric, and photoelectrochemical, were used for monitoring the signal of sweat biomarkers. Overall, these materials are brilliant electrode modifiers for the determination of sweat biomarkers. Full article

The development of photo-/electro-chemical and flexible electronics has stimulated research in catalysis, informatics, biomedicine, energy conversion, and storage applications. Gels (e.g., aerogel, hydrogel) comprise a range of polymers with three-dimensional (3D) network structures, where hydrophilic polyacrylamide, polyvinyl alcohol, copolymers, and hydroxides are the most widely studied for hydrogels, whereas 3D graphene, carbon, organic, and inorganic networks are widely studied for aerogels. Encapsulation of functional species with hydrogel building blocks can modify the optoelectronic, physicochemical, and mechanical properties. In addition, aerogels are a set of nanoporous or microporous 3D networks that bridge the macro- and nano-world. Different architectures modulate properties and have been adopted as a backbone substrate, enriching active sites and surface areas for photo-/electro-chemical energy conversion and storage applications. Fabrication via sol–gel processes, module assembly, and template routes have responded to professionalized features and enhanced performance. This review presents the most studied hydrogel materials, the classification of aerogel materials, and their applications in flexible sensors, batteries, supercapacitors, catalysis, biomedical, thermal insulation, etc. Full article

The detection of pathogens in medical wastewater is crucial due to the high content of pathogenic microorganisms that pose significant risks to public health and the environment. Medical wastewater, which includes waste from infectious disease and tuberculosis facilities, as well as comprehensive medical institutions, contains a variety of pathogens such as bacteria, viruses, fungi, and parasites. Traditional detection methods like nucleic acid detection and immunological assays, while effective, are often time-consuming, expensive, and not suitable for rapid detection in underdeveloped areas. Electrochemical biosensors offer a promising alternative with advantages including simplicity, rapid response, portability, and low cost. This paper reviews the sources of pathogens in medical wastewater, highlighting specific bacteria (e.g., E. coli, Salmonella, Staphylococcus aureus), viruses (e.g., enterovirus, respiratory viruses, hepatitis virus), parasites, and fungi. It also discusses various electrochemical biosensing techniques such as voltammetry, conductometry, impedance, photoelectrochemical, and electrochemiluminescent biosensors. These technologies facilitate the rapid, sensitive, and specific detection of pathogens, thereby supporting public health and environmental safety. Future research may should pay more attention on enhancing sensor sensitivity and specificity, developing portable and cost-effective devices, and innovating detection methods for diverse pathogens to improve public health protection and environmental monitoring. Full article

The problem of environmental pollution is one of the most important in the modern world. Pollution causes an increase in human diseases, the extinction of many species of plants and animals, global warming, and many weather anomalies. One of the great challenges for scientists is the development of methods for monitoring and removing the emerging pollutants. This review focuses on Metal–Organic Frameworks (MOFs) and their use as working material to construct different types of sensors for application in environmental pollution monitoring. In particular, the detection of heavy metals (mercury, lead, and arsenic) and organic compounds (drugs, biomolecules, and pesticides) are considered. The collected data show that photoelectrochemical (PEC) sensors based on MOFs are the most fascinating materials due to various combinations (e.g., surface modification) and operational possibilities. PEC sensors achieve enormous sensitivity, which increases even to the pico level, making it the best tool in sensing applications. This review also highlights the main sensor challenges. Most of them are concerned with the possibility of reusing the sensor, its regeneration, and safe disposal. In addition, more attention should be paid to the sensor manufacturing process, which often uses toxic compounds, and research to eliminate them in favor of non-toxic compounds. Full article

In this study, we investigated the influence of pH on the hydrothermal synthesis of copper (II) oxide CuO nanostructures with the aim of tuning their morphology. By varying the pH of the reaction medium, we successfully produced CuO nanostructures with three distinct morphologies including nanoparticles, nanorods, and nanosheets according to the pH levels of 4, 7, and 12, respectively. The observed variations in surface morphology are attributed to fluctuations in growth rates across different crystal facets, which are influenced by the presence of intermediate species within the reaction. This report also compared the structural and optical properties of the synthesized CuO nanostructures and explored their potential for photoelectrochemical glucose sensing. Notably, CuO nanoparticles and nanorods displayed exceptional performance with calculated limits of detection of 0.69 nM and 0.61 nM, respectively. Both of these morphologies exhibited a linear response to glucose within their corresponding concentration ranges (3–20 nM and 20–150 nM). As a result, CuO nanorods appear to be a more favorable photoelectrochemical sensing method because of the large surface area as well as the lowest solution resistance in electroimpedance analysis compared to CuO nanoparticles and nanosheets forms. These findings strongly suggest the promising application of hydrothermal-synthesized CuO nanostructures for ultrasensitive photoelectrochemical glucose biosensors. Full article