A dual-emission fluorescent aptasensor was developed for the rapid and simultaneous determination of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in food samples. The platform integration relies on a MXene-Ti3C2TX/MoS2 composite quencher paired with two aptamer-functionalized gold nanoclusters (AuNCs-Apt) emitting at 525 and 630 nm. The MXene-Ti3C2TX/MoS2 composite exhibited higher quenching performance than either individual component. Furthermore, the introduction of Mn2+ substantially enhanced the Delta F/F0 from 3.45 and 4.35 to 7.00 and 10.68, which was attributed to the reduced electrostatic repulsion and facilitated probe adsorption. Under the optimized conditions, the proposed aptasensor exhibited linear detection ranges of 0.05-200 ng/mL for both OTA and AFB1, with limits of detection of 15.7 pg/mL and 8.6 pg/mL, respectively. The assay could be completed within 40 min without complicated separation procedures. In addition, the sensor demonstrated high selectivity, repeatability, and reproducibility. In individual target assays, recoveries of 94.1%-108.0% were obtained in spiked red wine and corn flour samples, and the analytical results agreed well with certified reference values. Furthermore, analysis of mixed OTA/AFB1 samples with varying target ratios yielded acceptable recoveries of 94.5%-111.0%, confirming independent and interference-free dual-target quantification. Compared with previously reported methods, the developed platform combines simultaneous dual-target detection, a broad linear range, low detection limits, and a relatively short assay time within a single assay. These results indicate that the proposed aptasensor is a useful tool for rapid multiplex mycotoxin monitoring and food safety analysis.
ABSTRACT Tin perovskite solar cells (Sn‐PSCs) are promising lead‐free photovoltaics, but their performance is limited by facile Sn 2+ oxidation and severe non‐radiative recombination at the buried interface. Herein, a series of tetrabrominated bismaleimides ( MI, 1–4 ) bridged by phenyl ( MIP, 1 ), dimethylphenyl ( MIP’, 2 ), dimethylbiphenyl ( MIBp, 3 ), and tetramethylbiphenyl ( MIBp’, 4 ) units were synthesized and employed as multifunctional interface modifiers at the NiO x /FASnI 3 buried interface. The Lewis‐basic imide carbonyls and bromine substituents jointly improve precursor wetting, enlarge perovskite grains, and passivate the buried interface, suppressing the Sn 4+ fraction from 23.4% to 15.9%, while the aryl bridge tunes the energy‐level alignment for hole extraction. The champion MIBp device delivers a power conversion efficiency of 7.09% with a V OC of 0.551 V, a ~54% improvement over the NiO x control (4.61%), and the unencapsulated device retains 90% of its initial efficiency after 2000 h of storage. This work demonstrates tetrabrominated bismaleimides as a simple, anchoring‐group‐free molecular platform for regulating buried interfaces in lead‐free Sn‐PSCs.
ABSTRACT Copper(I) oxide (Cu 2 O) is a p‐type semiconductor with promising potential for photocatalytic applications; however, its practical application is limited by photo corrosion, which can reduce photocatalytic performance and stability. So, a ternary Cu 2 O/ZnO/polyaniline (PANI) composite was synthesized using a combination of sol‐mixing and in situ polymerization at room temperature to improve the photocatalytic performance in dyes photodegradation. In this work, Cu 2 O, Cu 2 O/ZnO, and Cu 2 O/ZnO/PANI composites with different aniline volumes (0.03, 0.05, and 0.10 mL) were prepared and characterized using FTIR, XRD, SEM‐EDS, PL spectroscopy, and UV–Vis DRS. The characterization results confirmed the characteristic functional groups and crystalline phases of the constituent materials. The incorporation of ZnO and PANI also modified the optical properties of Cu 2 O. The photocatalytic activity of the synthesized materials was evaluated using 10 ppm methylene blue (MB) under visible‐light irradiation for 120 min. The Cu 2 O/ZnO/PANI‐0.10 composite exhibited the highest MB degradation efficiency, reaching 90.01%. Due to the incorporation of PANI, the photoluminescence (PL) analysis confirmed that the intensity of Cu 2 O/ZnO/PANI photocatalysts was lower than that of the Cu 2 O/ZnO composite. The lowest PL intensity was Cu 2 O/ZnO/PANI‐0.10. It suggested a suppressed radiative recombination and more effective utilization of photogenerated charge carriers. Surprisingly, it was consistent with the highest MB degradation efficiency of this photocatalyst. The enhanced performance of the ternary composite was accompanied by improved photocatalyst reusability and structural stability. After three consecutive degradation cycles, the Cu 2 O/ZnO/PANI‐0.10 composite retained an MB degradation efficiency of 84.29%. Furthermore, FTIR and XRD analyses before and after the degradation cycles showed no significant changes in the chemical structure and crystalline phases of the composite. The improved photocatalytic performance suggests that the incorporation of ZnO and PANI can enhance the photocatalytic utilization of Cu 2 O in photocatalytic reactions.
ABSTRACT Acid Yellow‐25 (AY‐25) dye is a toxic pollutant that poses significant threats to both human health and the environment when discharged into aquatic systems. To resolve this problem, we have prepared graphene oxide (GO) nanoparticles (NPs), their binary (CuO/GO), and ternary (CuO/GO/TiO 2 ) nanocomposites (NCs). Pristine GO were synthesized by modified hummer's method, while copper oxide (CuO) and titanium dioxide (TiO 2 ) were integrated using simple co‐precipitation approach. The preparation of this system is supported by structural, surface, thermal, and morphological analysis. Under UV–Vis light irradiation, the CuO/GO/TiO 2 NCs degraded 93.79% of 80 ppm AY‐25 dye in 240 min at pH 5, catalyst loading of 0.03 g, and 303 K, surpassing GO and CuO/GO which exhibited degradation efficiencies of 71.47% and 84.96%, respectively, under identical conditions. The process of degradation was tested using pseudo‐first‐order and pseudo‐second‐order kinetics models, and thermodynamics approach: which gave information about the physicochemical nature of the photocatalytic process. Furthermore, the simultaneous incorporation of CuO and TiO 2 into GO enhanced light absorption, charge separation, and prolonged the lifetime of charge carriers, thereby increasing the photocatalytic activity. This study offers a straightforward method for designing and fabricating a novel ternary NCs photocatalyst with potential applications in wastewater treatment.
ABSTRACT Synthesis of multinary perovskite oxides is often limited by unstable phase formation and uncontrolled metal incorporation. Acidic redox‐assisted precipitation (ARP) offers stoichiometric redox control but has historically produced spinel or amorphous oxides rather than ABO 3 phases. Here we show that introducing citric acid redirects ARP into a phase‐selective, perovskite‐forming pathway, enabling the synthesis of phase‐pure La–Co–Mn oxides. Phase selection arises from competition between Co 2+ –MnO 4 − oxidation and citric‐acid‐to‐MnO 4 − reduction, establishing a redox stoichiometric window and enabling reaction‐selective metal incorporation that yields an A:B ratio approaching 1:1. The final composition reflects composition selection rather than precursor replication, revealing a previously unrecognized dimension of redox‐governed phase selection in multimetal oxide synthesis.
