Search Results (49)

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

One-dimensional (1D) nanomaterials have attracted considerable attention in the fabrication of nano-scale optoelectronic devices owing to their large specific surface areas, high surface-to-volume ratios, and directional electron transport channels. Compared to 1D metal oxide nanostructures, 1D metal sulfides have emerged as promising candidates for high-efficiency photodetectors due to their abundant surface vacancies and trap states, which facilitate oxygen adsorption and dissociation on their surfaces, thereby suppressing intrinsic carrier recombination while achieving enhanced optoelectronic performance. This review focuses on recent advancements in the performance of photodetectors fabricated using 1D binary metal sulfides as primary photosensitive layers, including nanowires, nanorods, nanotubes, and their heterostructures. Initially, the working principles of photodetectors are outlined, along with the key parameters and device types that influence their performance. Subsequently, the synthesis methods, device fabrication, and photoelectric properties of several extensively studied 1D metal sulfides and their composites, such as ZnS, CdS, SnS, Bi₂S₃, Sb₂S₃, WS₂, and SnS₂, are examined. Additionally, the current research status of 1D nanostructures of MoS₂, TiS₃, ReS₂, and In₂S₃, which are predominantly utilized as 2D materials, is explored and summarized. For systematic performance evaluation, standardized metrics encompassing responsivity, detectivity, external quantum efficiency, and response speed are comprehensively tabulated in dedicated sub-sections. The review culminates in proposing targeted research trajectories for advancing photodetection systems employing 1D binary metal sulfides. Full article

The efficient separation of photo-generated electrons and holes is significantly importance for enhancing photocatalytic performance. However, there are few reports on precisely constructing interfaces within a single nanocrystal to investigate the mechanism of photoinduced carrier transfer. In this study, nanorod heterodimer-structured CuS/Zn_xCd_1−xS heteronanocrystals (CuS/ZnCdS HNCs) were successfully synthesized as a typical model to explore the photoinduced carrier dynamics in the photocatalytic hydrogen evolution reaction (HER). The CuS/ZnCdS HNCs exhibited a photocatalytic hydrogen evolution activity of 146 mmol h⁻¹ g⁻¹ under visible light irradiation, which is higher than most reported values. Moreover, after 15 h of hydrogen production cycling tests, we found that the material maintained high hydrogen production performance, indicating excellent stability. The CuS/ZnCdS HNCs achieved an apparent quantum yield (AQY) of 69.2% at 380 nm, which is the highest value reported so far for ZnCdS- or CuS-based photocatalysts. The remarkable activity and stability of the CuS/ZnCdS HNCs were attributed to the strong internal electric field (IEF) and Z-scheme mechanism, which facilitate efficient charge separation, as demonstrated by in situ X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) analyses. This discovery provides a new approach for constructing Z-scheme heterogeneous copper-based nanocomposites within nanocrystals and offers guidance for improving photocatalytic activity. Full article

Circularly polarized light (CPL) detection sensors have significant potential for applications in quantum communication and biosensing. In this work, we propose a three-layer complementary chiral metasurface (TCCM) for on-chip integration in the mid-infrared range (2–6 μm). The TCCM consists of an Al nanorod layer, a SiO₂ dielectric layer, and an Al nanoslit layer, with strong circular dichroism (CD) achieved through the symmetry breaking of the inclined rectangular rods. Finite-difference time-domain (FDTD) simulation results demonstrate that the electric fields excited by left circularly polarized (LCP) light and right circularly polarized (RCP) light exhibit different bonding and antibonding modes, which explains the CD mechanism. The CD response and spectral tunability are influenced by the angle and length of the inclined rectangular rods. Through simulation optimization of structural parameters, a maximum CD value of 0.72 is achieved. Compared to traditional multilayer chiral metasurfaces, the TCCM simplifies the fabrication process. These findings provide valuable insights and practical strategies for the development of compact infrared devices, particularly in optical communication, chiral sensing, and full-Stokes polarization detection. Full article

In the present study, a green, scalable, and environmentally friendly approach was developed for the fabrication of Bi₂S₃-decorated CdS nanoparticles with an efficient hydrogen generation ability from the water. As a sulfur source, thiourea was used. The process was completed in two stages: mechanical activation and thermal annealing. The presence of spherical CdS nanoparticles and Bi₂S₃ nanorods in the CdS/Bi₂S₃ nanocomposite was confirmed and proved by XRD, Raman spectroscopy, SEM-EDS, and TEM. The synthesized CdS/Bi₂S₃ nanocomposites were evaluated for their photocatalytic hydrogen evolution capabilities. The CdS/Bi₂S₃ photocatalyst exhibited 25% higher photocatalytic activity compared to CdS, reaching a hydrogen evolution rate of 996.68 μmol h⁻¹g⁻¹ (AQE 0.87%) after 3.5 h under solar-light irradiation. Full article

Semiconductor nanorods (NRs) have great potential in optoelectronic devices for their unique linearly polarized luminescence which can break the external quantum efficiency limit of light-emitting diodes (LEDs) based on spherical quantum dots. Significant progress has been made for developing red, green, and blue light-emitting NRs. However, the synthesis of NRs emitting in the deep red region, which can be used for accurate red LED displays and promoting plant growth, is currently less explored. Here, we report the synthesis of deep red CdSeTe/CdZnS/ZnS dot-in-rod core/shell NRs via a seeded growth method, where the doping of Te in the CdSe core can extend the NR emission to the deep red region. The rod-shaped CdZnS shell is grown over CdSeTe seeds. By growing a ZnS passivation shell, the CdSeTe/CdZnS/ZnS NRs exhibit a photoluminescence emission peak at 670 nm, a full width at a half maximum of 61 nm and a photoluminescence quantum yield of 45%. The development of deep red NRs can greatly extend the applications of anisotropic nanocrystals. Full article

Manipulating plasmonic chirality has shown promising applications in nanophotonics, stereochemistry, chirality sensing, and biomedicine. However, to reconfigure plasmonic chirality, the strategy of constructing chiral plasmonic systems with a tunable morphology is cumbersome and complicated to apply for integrated devices. Here, we present a simple and effective method that can also manipulate chirality and control chiral light–matter interactions only via strong coupling between chiral plasmonic nanoparticles and excitons. This paper presents a chiral plexcitonic system consisting of L-shaped nanorod dimers and achiral molecule excitons. The circular dichroism (CD) spectra in our strong-coupling system can be calculated by finite element method simulations. We found that the formation of the chiral plexcitons can significantly modulate the CD spectra, including the appearance of new hybridized peaks, double Rabi splitting, and bisignate anti-crossing behaviors. This phenomenon can be explained by our extended coupled-mode theory. Moreover, we explored the applications of this method in enantiomer ratio sensing by using the properties of the CD spectra. We found a strong linear dependence of the CD spectra on the enantiomer ratio. Our work provides a facile and efficient method to modulate the chirality of nanosystems, deepens our understanding of chiral plexcitons in nanosystems, and facilitates the development of chiral devices and chiral sensing. Full article

N-butanol (C₄H₉OH) is a volatile organic compound (VOC) that is susceptible to industrial explosions. It has become imperative to develop n-butanol sensors with high selectivity and fast response and recovery kinetics. CdS/Ag₂S composite nanomaterials were designed and prepared by the solvothermal method. The incorporation of Ag₂S engendered a notable augmentation in specific surface area and a consequential narrow band gap. The CdS/Ag₂S-based sensor with 3% molar ratio of Ag₂S, operating at 200 °C, demonstrated a remarkably elevated response (S = R_a/R_g = 24.5) when exposed to 100 ppm n-butanol, surpassing the pristine CdS by a factor of approximately four. Furthermore, this sensor exhibited notably shortened response and recovery times, at a mere 4 s and 1 s, respectively. These improvements were ascribed to the one-dimensional single-crystal nanorod structure of CdS, which provided an effective path for expedited electron transport along its axial dimension. Additionally, the electron and chemical sensitization effects resulting from the modification with precious metal sulfides Ag₂S were the primary reasons for enhancing the sensor response. This work can contribute to mitigating the safety risks associated with the use of n-butanol in industrial processes. Full article

ZrO₂-based nanocomposites are highly versatile materials with huge potential for photocatalysis. In this study, ZrO₂-CdWO₄ nanocomposites (NC) were prepared via the green route using aqueous Brassica rapa leaf extract, and its photocatalytic water-splitting application was evaluated. Brassica rapa leaf extract acts as a reducing agent and abundant phytochemicals are adsorbed onto the nanoparticle surfaces, improving the properties of ZrO₂-CdWO₄ nanocomposites. As-prepared samples were characterized by using various spectroscopic and microscopic techniques. The energy of the direct band gap (E_g) of ZrO₂-CdWO₄ was determined as 2.66 eV. FTIR analysis revealed the various functional groups present in the prepared material. XRD analysis showed that the average crystallite size of ZrO₂ and CdWO₄ in ZrO₂-CdWO₄ was approximately 8 nm and 26 nm, respectively. SEM and TEM images suggested ZrO₂ deposition over CdWO₄ nanorods, which increases the roughness of the surface. The prepared sample was also suggested to be porous. BET surface area, pore volume, and half pore width of ZrO₂-CdWO₄ were estimated to be 19.6 m²/g. 0.0254 cc/g, and 9.457 Å, respectively. PL analysis suggested the conjugation between the ZrO₂ and CdWO₄ by lowering the PL graph on ZrO₂ deposition over CdWO₄. The valence and conduction band edge positions were also determined for ZrO₂-CdWO₄. These band positions suggested the formation of a type I heterojunction between ZrO₂ and CdWO₄. ZrO₂-CdWO₄ was used as a photocatalyst for hydrogen production via water splitting. Water-splitting results confirmed the ability of the ZrO₂-CdWO₄ system for enhanced hydrogen production. The effect of various parameters such as photocatalyst amount, reaction time, temperature, water pH, and concentration of sacrificial agent was also optimized. The results suggested that 250 mg of ZrO₂-CdWO₄ could produce 1574 µmol/g after 5 h at 27 °C, pH 7, using 30 vol. % of methanol. ZrO₂-CdWO₄ was reused for up to seven cycles with a high hydrogen production efficiency. This may prove to be useful research on the use of heterojunction materials for photocatalytic hydrogen production. Full article

Ultra-thin two-dimensional materials are attracting widespread interest due to their excellent properties, and they are becoming ideal candidates for a variety of energy and environmental photocatalytic applications. Herein, CdS nanorods are successfully grown in situ between a monolayer of g-C₃N₄ using a chemical water bath method. Continuous ultrasound is introduced during the preparation process, which effectively prevents the accumulation of a g-C₃N₄ layer. The g-C₃N₄@CdS nanocomposite exhibits significantly enhanced photocatalytic activity for hydrogen production under visible-light irradiation, which is attributed to a well-matched band structure and an intimate van der Waals heterojunction interface. The mechanism of photocatalytic hydrogen production is discussed in detail. Moreover, our work can serve as a basis for the construction of other highly catalytically active two-dimensional heterostructures. Full article

This study involves the fabrication and characterization of a multifunctional therapeutic nanocomposite system, as well as an assessment of its in vitro efficacy for breast cancer treatment. The nanocomposite system combines gold nanorods (GNRs) and gold nanoclusters (GNCs) to enable a combination of photothermal therapy and doxorubicin-based chemotherapy. GNRs of various sizes but exhibiting similar absorbance spectra were synthesized and screened for photothermal efficiency. GNRs exhibiting the highest photothermal efficiency were selected for further experiments. GNCs were synthesized in bovine serum albumin (BSA) and integrated into citrate-capped GNRs using layer-by-layer assembly. Glutaraldehyde crosslinking with the lysine residues in BSA was employed to immobilize the GNCs onto the GNRs, forming a stable “soft gel-like” structure. This structure provided binding sites for doxorubicin through electrostatic interactions and enhanced the overall structural stability of the nanocomposite. Additionally, the presence of GNCs allowed the nanocomposite system to emit robust fluorescence in the range of ~520 nm to 700 nm for self-detection. Hyaluronic acid was functionalized on the exterior surface of the nanocomposite as a targeting moiety for CD44 to improve the cellular internalization and specificity for breast cancer cells. The developed nanocomposite system demonstrated good stability in vitro and exhibited a pH- and near-infrared-responsive drug release behavior. In vitro studies showed the efficient internalization of the nanocomposite system and reduced cellular viability following NIR irradiation in MDA-MB-231 breast cancer cells. Together, these results highlight the potential of this nanocomposite system for targeted breast cancer therapy. Full article

Biological applications of silver nanoparticles (AgNPs) depend on the covalently attached or adsorbed proteins. A series of biological effects of AgNPs within cells are determined by the size, shape, aspect ratio, surface charge, and modifiers. Herein, the morphology dependent interaction between AgNPs and protein was investigated. AgNPs with three different morphologies, such as silver nanospheres, silver nanorods, and silver nanotriangles, were employed to investigate the morphological effect on the interaction with a model protein: bovine serum albumin (BSA). The adsorptive interactions between BSA and the AgNPs were probed by UV-Vis spectroscopy, fluorescence spectroscopy, dynamic light scattering (DLS), Fourier transform infrared spectrometry (FTIR), transmission electron microscopy (TEM), and circular dichroism (CD) techniques. The results revealed that the particle size, shape, and dispersion of the three types of AgNPs markedly influence the interaction with BSA. Silver nanospheres and nanorods were capsulated by protein coronas, which led to slightly enlarged outer size. The silver nanotriangles evolved gradually into nanodisks in the presence of BSA. Fluorescence spectroscopy confirmed the static quenching the fluorescence emission of BSA by the three AgNPs. The FTIR and CD results suggested that the AgNPs with different morphologies had different effects on the secondary structure of BSA. The silver nanospheres and silver nanorods induced more pronounced structural changes than silver nanotriangles. These results suggest that the formation of a protein corona and the aggregation behaviors of AgNPs are markedly determined by their inherent morphologies. Full article

Photocatalytic H₂ production provides an ideal way to alleviate the energy crisis and solve environmental problems. In this paper, the metallic MoS₂/WS₂ dual cocatalysts are prepared through the in situ growth of 1T-WS₂ on the surface of 1T-MoS₂ via a solvothermal method. The ternary cross-linked MoS₂/WS₂/CdS photocatalysts are finally constructed by growing CdS nanorods on MoS₂/WS₂ cocatalysts. The XRD and TEM results show that ternary cross-linked MoS₂/WS₂/CdS photocatalysts with close interfacial contact were successfully synthesized. The results of Photoluminescence (PL) and photoelectrochemical tests show that MoS₂/WS₂/CdS has the lowest hydrogen evolution overpotential and the highest charge separation efficiency. This is due to the synergistic effect between WS₂ and MoS₂, which further accelerates the transfer of photogenerated electrons and inhibits the recombination of carriers. The hydrogen evolution rate of the MoS₂/WS₂/CdS composite is 12.12 mmol·g⁻¹·h⁻¹, which is 4.57 times that of pristine CdS. The AQY at λ = 420 nm is 58.9%. Full article

Solar energy harvesting using semiconductor photocatalysis offers an enticing solution to two of the biggest societal challenges, energy scarcity and environmental pollution. After decades of effort, no photocatalyst exists which can simultaneously meet the demand for excellent absorption, high quantum efficiency and photochemical resilience/durability. While CdS is an excellent photocatalyst for hydrogen evolution, pollutant degradation and organic synthesis, photocorrosion of CdS leads to the deactivation of the catalyst. Surface passivation of CdS with 2D graphitic carbon nitrides (CN) such as g-C₃N₄ and C₃N₅ has been shown to mitigate the photocorrosion problem but the poor oxidizing power of photogenerated holes in CN limits the utility of this approach for photooxidation reactions. We report the synthesis of exfoliated 2D nanosheets of a modified carbon nitride constituted of tris-s-triazine (C₆N₇) linked pyromellitic dianhydride polydiimide (CN:PDI) with a deep oxidative highest occupied molecular orbital (HOMO) position, which ensures sufficient oxidizing power for photogenerated holes in CN. The heterojunction formed by the wrapping of mono-/few layered CN:PDI on CdS nanorods (CdS/CN:PDI) was determined to be an excellent photocatalyst for oxidation reactions including photoelectrochemical water splitting, dye decolorization and the photocatalytic conversion of benzyl alcohol to benzaldehyde. Extensive structural characterization using HR-TEM, Raman, XPS, etc., confirmed wrapping of few-layered CN:PDI on CdS nanorods. The increased photoactivity in CdS/CN:PDI catalyst was ascribed to facile electron transfer from CdS to CN:PDI in comparison to CdS/g-C₃N₄, leading to an increased electron density on the surface of the photocatalyst to drive chemical reactions. Full article

Herein, we synthesized the cadmium sulfide nanoparticles (CdS-NPs) coated zinc oxide nanorods (ZnO-NRs) core-shell like CdS-NPs@ZnO-NRs heterojunction for photo(electro)chemical applications. The CdS-NPs and ZnO-NRs were synthesized through a simple hydrothermal path. The physicochemical and optoelectronic properties of the as-prepared catalysts are characterized by various spectroscopy techniques, such as FTIR, XRD, SEM, TEM, EDX, VB-XPS, DRS, and PL. The photocatalytic performances of the CdS-NPs@ZnO-NRs catalyst were evaluated by photodegradation of tetracycline (TC) in aqueous media under visible-light irradiation, which demonstrated 94.07 % of removal (k’ = 0.0307 min⁻¹) within 90 min. On the other hand, the photoelectrochemical (PEC) water-oxidation/oxygen-evolution reaction (OER) was performed, which resulted in the photocurrent density of 3.002 mA/cm² and overpotential (at 2 mA/cm²) of 171 mV (vs RHE) in 1.0 M KOH under AM 1.5G illumination. The reactive species scavenging experiment demonstrates the significant contributions of photogenerated holes towards TC removal. Furthermore, the Z-scheme CdS-NPs@ZnO-NRs core-shell heterojunction exhibits high efficiency, recyclability, and photostability, demonstrating that the CdS-NPs@ZnO-NRs is a robust photo(electro)catalyst for visible-light PEC applications. Full article