Nanocrystal quantum dots (QDs) provide tunable optoelectronic properties on the basis of their dimension. CdSe QDs, which are size-dependent colloidal nanocrystals, are used for efficient electrochromic devices owing to their unique properties in modulating quantum confinement, resulting in enhanced electron insertion during the electrochromic process. Incorporating a well-known metal oxide electrochromic material such as WO3 into CdSe QDs enhances the redox process. Herein, we propose a facile method for producing and optimizing CdSe QDs doped in WO3. The fabrication of the electrochromic film involves a solution and annealing process. Moreover, the effect of the QD size to optimize the electrochromic layer is studied. As a result, the coloration efficiency of WO3 and optimized CdSe QD–WO3 are obtained as 68.6 and 112.3 cm2/C, respectively. Thus, size-tunable nanocrystal QDs combined with a …
Recently, quantum dot light‐emitting devices have drawn significant attention in the field of display technologies due to their low power consumption, high color purity, and solution processability. Among these, halide perovskite quantum dots (HPQDs) have emerged as the most efficient quantum dots for light‐emitting applications, with photoluminescence quantum yields (PLQYs) approaching 100%. In this Review, the current progress of HPQDs, including their synthesis, properties, and applications in light‐emitting devices, are summarized and discussed. First, the optical and physical properties of HPQDs and their advantages as emissive layers in light‐emitting devices are discussed. Next, synthetic strategies for the synthesis of high‐quality and high‐PLQY HPQDs are introduced. Subsequently, critical parameters affecting the properties and structures of HPQDs, such as the role of surface passivation, fast anion …
Description Two-dimensional transition metal dichalcogenides (2D-TMDs), such as MoS2 and WS2 nanosheets (MeS2-NS), are reported as efficient catalysts for hydrogen evolution reaction (HER), which can potentially replace the expensive platinum catalyst. In this report, 1T phase MeS2 (1T-MeS2) NS are synthesized by lithium-intercalation exfoliation method, subsequently being modified by amorphous MoSx and WSx (MeSx@MeS2-NS) through a solvothermal method. Interestingly, MeSx@MeS2-NS significantly improves the HER performance compared with bare MeS2-NS as catalysts. Among these, MoSx@MoS2 is observed to be the best combination for HER, with an onset potential and Tafel slope of 114 mV and 45.1 mV decade−1, respectively. The enhancement in the HER device using MeSx@MeS2-NS as the catalyst originates from vertically grown MeSx, which provides additional active sulfur sites for the …
There has been considerable research to engineer composites of transition metal dichalcogenides with other materials to improve their catalytic performance. In this work, we present a modified solution-processed method for the formation of molybdenum selenide (MoSe 2) nanosheets and a facile method of structuring composites with graphene oxide (GO) or reduced graphene oxide (rGO) at different ratios to prevent aggregation of the MoSe 2 nanosheets and hence improve their electrocatalytic hydrogen evolution reaction performance. The prepared GO, rGO, and MoSe 2 nanosheets were characterized by X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The electrocatalytic performance results showed that the pure MoSe 2 nanosheets exhibited a somewhat high Tafel slope of 80 mV/dec, whereas the MoSe 2-GO and MoSe 2-rGO composites showed lower Tafel slopes of 57 and 67 mV/dec at ratios of 6: 4 and 4: 6, respectively. We attribute the improved catalytic effects to the better contact and faster carrier transfer between the edge of MoSe 2 and the electrode due to the addition of GO or rGO. View Full-Text
The issues of global warming and fossil fuel shortage have increased the demand for clean and renewable energy. Many researchers are investigating strategies to produce hydrogen and reduce CO2 by using solar power. Two-dimensional (2D) materials, such as graphene, graphene derivatives, and transition metal dichalcogenides (TMDs), have been extensively used owing to their extraordinary electronic and optical properties. In this review, we investigate the recent developments in 2D materials for photocatalytic applications involving the hydrogen evolution reaction and CO2 reduction. The synthesis methods and the photocatalytic properties of TMDs and graphene-based 2D materials are thoroughly discussed. Moreover, a summary of the recently developed 2D nanostructures and devices for solar hydrogen production and CO2 reduction is presented, and it is revealed that the use of 2D catalyst materials …
In this paper, a facile method for synthesizing WS2 nanoflowers (NFs) and CdSe quantum dots (QDs) using hydrothermal and hot injection methods, are reported, respectively. Additionally, the photocatalytic activity of a CdSe QDs/WS2 NF nanocomposite is analyzed in a typical three‐electrode electrochemical cell. It is found that the CdSe QDs/WS2 NF hybrid exhibits a current density of −1.12 mA at 0 V and a Tafel slope of 82 mV dec−1, which are superior to the values of bare WS2 NFs (current density of −0.25 mA and Tafel slope of 150 mV dec−1). This improvement of photocatalytic performance is attributed to the wide range of light absorption for e−/h+ generation provided by the CdSe QDs, as well as the large surface area and numerous active sites for hydrogen production provided by WS2 NFs. Therefore, the CdSe QDs/WS2 NF hybrid structure is a promising candidate for highly effective and stable …
Trong dự án này, chúng tôi sẽ phát triển một loại keo dán sinh học từ hỗn hợp tinh bột biến tính và chitosan phân tử lượng thấp tan trong nước. Loại keo này có thể tiêm được và có khả năng kháng khuẩn.
