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Electrochemically switchable electrochemiluminescent sensor constructed based on inorganic perovskite quantum dots synthesized with microwave irradiation
摘要： Microwave irradiation was employed to synthesize inorganic perovskite quantum dots (IPQDs) which were demonstrated to be monoclinic phase and behaved tunable photoluminescent emissions across the entire visible light spectrum. The microwave-based synthetic method was proved to be easy-operation, high-throughput and low-cost. These microwave-synthesized IPQDs exhibited electrochemically switchable electrochemiluminescence (ECL). Obvious ECL was obtained when holes were injected into the electron-injected IPQDs while almost no ECL was observed in the reverse process. ECL of IPQDs gave promise for constructing electrochemiluminescent sensors for hydrogen peroxide (H2O2) and dopamine (DA) detection. Linear relationships between ECL intensities and H2O2/DA concentrations were detected and satisfactory correlation coefficients were obtained. Our results shed light on the ECL of microwave-synthesized IPQDs.
关键词： electrochemiluminescent sensor,inorganic perovskite quantum dots,electroluminescence,microwave
更新于2025-09-23 15:21:01
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Optical oxygen sensing by MPA-capped CdTe quantum dots immobilized in mesoporous silica
摘要： A novel nanocomposite luminescent material was prepared by taking advantage of the versatile wet impregnation method for the dispersion of CdTe quantum dots (QDs) into mesoporous silica host matrix and thus providing great interaction between oxygen and QDs, with potential application in an optical oxygen sensor. The optical/spectroscopic properties of the QDs suspended in aqueous media and incorporated in mesoporous silica were evaluated as a function of aging time, temperature variation and oxygen concentration. Luminescence quenching studies were carried out for both QDs suspended in solution and loaded into the silica matrix, in the presence of varying O2 concentration. By Stern-Volmer plot analysis, obtained at different temperatures, it was possible to verify the existence of two types of emission quenching mechanisms for CdTe QDs. After aging for 120 days at room temperature, the QDs in colloidal suspension displayed a small red-shifted emission, which was interpreted as a decreased bandgap energy owing to the increase in the nanocrystal size. In contrast, the emission spectrum of CdTe QDs loaded into the mesoporous SiO2 matrix remained unchanged after aging for the same time at ambient temperature. The presented results will contribute to the discernment of oxygen quenching mechanisms and chemical stability of optical sensors based on CdTe QDs.
关键词： oxygen sensors,mesoporous silica,Quantum Dots,CdTe,wet impregnation,fluorescence quenching
更新于2025-09-23 15:21:01
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Surface and intrinsic contributions to extinction properties of ZnSe quantum dots
摘要： This work studies extinction properties of ZnSe quantum dots terminated with either Se-surface or Zn-surface (Se-ZnSe or Zn-ZnSe QDs). In addition to commonly observed photoluminescence quenching by anionic surface sites, Se-ZnSe QDs are found to show drastic signatures of Se-surface states in their UV–visible (Vis) absorption spectra. Similar to most QDs reported in literature, monodisperse Zn-ZnSe QDs show sharp absorption features and blue-shifted yet steep absorption edge respect to the bulk bandgap. However, for monodisperse Se-ZnSe QDs, all absorption features are smeared and a low-energy tail is identified to extend to an energy window below the bulk ZnSe bandgap. Along increasing their size, a cyclic growth of ZnSe QDs switches their surface from Zn-terminated to Se-terminated ones, which confirms that the specific absorption signatures are reproducibly repeated between those of two types of the QDs. Though the extinction coefficients per unit of Se-ZnSe QDs are always larger than those of Zn-ZnSe QDs with the same size, both of them approach the same bulk limit. In addition to contribution of the lattice, extinction coefficients per nanocrystal of Zn-ZnSe QDs show an exponential term against their sizes, which is expected for quantum-confinement enhancement of electron–hole wavefunction overlapping. For Se-ZnSe QDs, there is the third term identified for their extinction coefficients per nanocrystal, which is proportional to the square of size of the QDs and consistent with surface contribution.
关键词： ZnSe,quantum dots,surface state,extinction coefficient
更新于2025-09-23 15:21:01
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The effect of hydrothermal conditions on photoluminescence properties of rice husk-derived silica-carbon quantum dots for methylene blue degradation
摘要： Carbon quantum dots (CQDs) have potential to replace metal-based quantum dots due to its low-toxicity. However, studies on CQDs preparation were dominated by synthetic carbon precursors. Switching the precursors into natural ingredient is preferred since they are highly abundant and low-cost. In this study, composite of silica-carbon quantum dots (Si-CQDs) were fabricated from rice husk through a hydrothermal process. Si-CQDs with diverse properties are beneficial for its application in the future; therefore, the variation of hydrothermal conditions (i.e., temperature and pH) was performed to investigate their influence on its properties. Investigation using HRTEM, XPS, Raman spectroscopy, and UV-Vis spectroscopy suggested that hydrothermal conditions affect carbonization reaction. Hydrothermal temperature controls carbonization rate of rice husk ash, while acid addition accelerates polymerization and base addition tends to cut more carbons into small particles. The photoluminescence (PL) analysis showed that the obtained Si-CQD samples have emission in the range of 469–552 nm with various intensities. The application of sole Si-CQDs was evaluated in methylene blue (MB) degradation under visible light irradiation.
关键词： Hydrothermal,Carbon quantum dots,Photocatalyst,Photoluminescence,Rice husk
更新于2025-09-23 15:21:01
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Protein Corona Formation of Human Serum Albumin with Carbon Quantum Dots from Roasted Salmon
摘要： As the food-borne nanoparticles enter the biological system, they will contact with various proteins to form protein coronas, which can affect their physicochemical properties and biological identity. In this study, the protein corona formation of carbon quantum dots (CQDs) from roast salmon with human serum albumin (HSA), as well as biological identity involving cell apoptosis, energy, glucose and lipid metabolism and acute toxicity in mice, were investigated. The HSA-CQD coronas formed between HSA and CQDs via static binding mechanism, and the binding site of CQDs on HSA located both in Sudlow’s site I and site II. The HSA-CQD coronas entered the cytoplasm and present in lysosomes or autolysosomes. Importantly, the HSA coronas mitigated the cytotoxicity of CQDs from 18.65% to 9.26%, and the energy metabolism was rectified from glycolytic to aerobic metabolism. The glucose and lipid metabolite profile of the HSA-CQD coronas differed from that of the CQDs, indicating that HSA-CQD coronas rectified disturbance in metabolism. Histopathological and blood biochemical analysis revealed no statistically significant difference between the testing and control mice after a single CQDs dose of 2000 mg/kg body weight. Overall, the results confirmed the formation of protein corona between HSA and food-borne fluorescent CQDs, and could be helpful for evaluating the safety of fluorescent CQDs from roast food items.
关键词： cytotoxicity,acute toxicity,protein coronas,human serum albumin,carbon quantum dots,metabolism,food-borne nanoparticles
更新于2025-09-23 15:21:01
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An inverted ZnO/P3HT:PbS bulk-heterojunction hybrid solar cell with a CdSe quantum dot interface buffer layer
摘要： An inverted bulk-heterojunction (BHJ) hybrid solar cell having the structure ITO/ZnO/P3HT:PbS/Au was prepared under ambient conditions and the device performance was further enhanced by inserting an interface buffer layer of CdSe quantum dots (QDs) between the ZnO and the P3HT:PbS BHJ active layer. The device performance was optimized by controlling the size of the CdSe QDs and the buffer layer thickness. The buffer layer, with an optimum thickness and QD size, has been found to promote charge leading to an increased open-circuit voltage (VOC), extraction and reduces interface recombinations, short circuit current density (JSC), fill factor (FF) and power conversion efficiency (PCE). About 40% increase in PCE from 1.7% to 2.4% was achieved by the introduction of the CdSe QD buffer layer, whose major contribution comes from a 20% increase of VOC.
关键词： CdSe quantum dots,inverted bulk-heterojunction,interface buffer layer,hybrid solar cell,power conversion efficiency
更新于2025-09-23 15:21:01
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[IEEE 2019 20th International Conference on Electronic Packaging Technology(ICEPT) - Hong Kong, China (2019.8.12-2019.8.15)] 2019 20th International Conference on Electronic Packaging Technology(ICEPT) - Self-Assembled Copper Nanoclusters-Based White Light Emitting Diodes With High Performance
摘要： Metal nanoclusters, composed of a few to a hundred atoms, whose size is close to the Fermi wavelength of electrons, have become a new type of phosphor materials due to their unique electronic structure and excellent performance. And metal nanoclusters have been applied in various applications, such as bioimaging, chemical biosensing, optoelectronic devices, etc. At present, researchers have synthesized and studied gold and silver nanoclusters, but Au and Ag nanoclusters have one drawback: expensive. At the same time, copper nanoclusters have attracted people's attention because of their non-toxicity, large Stokes shift and economy. In this paper, we fabricated 1-dodecanethiol (DT)-capped self-assembled copper nanoclusters in colloidal solution with yellow light emission and characterized the prepared self-assembled copper nanoclusters by UV–visible spectra, TEM and PL characterization methods. Self-assembled copper nanoclusters were used as color conversion layers for the manufacture of white light-emitting diodes. The prepared white LED has good color properties, the color rendering index was 79.3, the CIE color coordinates located at (0.3213,0.3255) and the color temperature was 6067K. This indicates that copper nanoclusters show potential for applications in white lighting emitting diodes as a new type of low-cost and superior photoluminescent material candidates.
关键词： Copper Nanoclusters,Photoluminescence,White Light Emitting Diodes,Quantum Dots
更新于2025-09-23 15:21:01
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[IEEE 2018 23rd Opto-Electronics and Communications Conference (OECC) - Jeju Island, Korea (South) (2018.7.2-2018.7.6)] 2018 23rd Opto-Electronics and Communications Conference (OECC) - 2.8?μm infrared photodetectors based on PbSe colloidal quantum dot films
摘要： In this study, we synthesized monodisperse and high purity PbSe CQDs and then demonstrated the photodetectors working at different wavelengths up to 2.8 μm. Colloidal quantum dots (CQDs) have been studied extensively due to their attractive optoelectronic properties such as high luminescence efficiency, large dipole moment, strong light absorption, good photo-stability, and multiple electron hole pair generation. More importantly, the strong quantum confinement effect allows us to tailor the energy band gap of these materials by controlling their size in a cost-effective wet chemical synthesis. These advantages bring CdSe-based CQDs to a competitive market of lighting and display technology today. The research on lead based chalcogenide (PbTe, PbS, and PbSe) CQDs for infrared applications has also received much scientific and technological attention because of the possibility to tune the bandgap in the infrared wavelength range. Among lead based chalcogenide family, lead selenide (PbSe) CQDs have received more attention in not only photodetectors but also many infrared optoelectronic applications like solar cells, light emitting diodes, etc [1-4]. In the present work, we report about high performance photodetectors at a broad spectral range, for the first time, up to 2.8 μm based on our high quality, monodisperse PbSe CQDs. We deposited thin films of synthesized PbSe CQDs on the patterned interdigitated platinum electrodes by a drop casting method to create photodetectors. These photodetectors with different thicknesses of the PbSe CQD film were studied and optimized in detail for the best performance. The photocurrent responses were recorded as a function of bias voltage using infrared LED illuminations with wavelengths of up to 2.8 μm.
关键词： infrared photodetectors,detectivity,responsivity,PbSe colloidal quantum dots,photocurrent
更新于2025-09-23 15:21:01
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Non-volatile Organic Transistor Memory based on Black Phosphorus Quantum dots as Charge Trapping Layer
摘要： High performance organic nano-floating gate transistor memory (NFGTM) has important prerequisites of low processing temperature, solution–processable layers and charge trapping medium with high storage capacity. We demonstrate organic NFGTM using black phosphorus quantum dots (BPQDs) as a charge trapping medium by simple spin-coating and low processing temperature (< 120 oC). The BPQDs with diameter of 12.6 ± 1.5 nm and large quantum confined bandgap of ~2.9 eV possess good charge trapping ability. The organic memory device exhibits excellent memory performance with a large memory window of 61.3 V, write-read-erase-read cycling endurance of 103 for more than 180 cycles and reliable retention over 10,000 sec. In addition, we successfully improved the memory retention to ON/OFF current ratio > 104 over 10,000 sec by introducing PMMA as the tunneling layer.
关键词： floating gate transistor,organic memory,solution-processed,Black phosphorus,quantum dots
更新于2025-09-23 15:21:01
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Influence of Carbon Quantum Dots on the Biome
摘要： The latest class of engineered nanomaterials, viz., carbon quantum dots (CQDs), has attracted attention because they are synthesized through green chemical procedures and from organic waste matter. The synthesis of these nano-sized particles synthesized from biomass such as fruit peel and other organic matter results in mixtures of CQD species that di?er in chemical identity, activity and photo-physical properties. Generally used collectively as chemically heterogeneous ensemble, they have already had an impact on multiple sectors of our environment by use as wastewater sensors, switches, model agro-fertilizers, and in biomedicine. The transitioning of their applications to crops is an important crossover point that calls for an accurate and detailed assessment of their genomic, proteomic, and metabolomics impact on agriculturally important crops and produce. We review the current status of CQDs vis-à-vis their impact on the biosphere via recent model studies and comment on the knowledge gaps that need to be bridged to ensure their safe use in agronomy. A detailed knowledge of their impact on aquatic systems and the food-chain is critical for human and environmental safety and sustainability.
关键词： agriculture,environmental implications,Carbon Quantum Dots,toxicity
更新于2025-09-23 15:21:01