Publications by authors named "Mengda He"

Article Synopsis
  • - The text discusses the potential of using halide perovskite nanocrystals (NCs) for photocatalytic carbon dioxide reduction, which could help address global warming and energy shortages via fuel production.
  • - The researchers improved the stability of these nanocrystals by embedding them in stable titania microspheres (TMs), leading to a significant increase in efficiency for producing carbon-based fuels from CO, surpassing previous methods.
  • - Enhanced charge separation due to an internal electric field within the microspheres boosts the performance of the CsPbBr/TMs, suggesting a path forward for developing more effective and stable photocatalysts.
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Article Synopsis
  • * A new strategy has been developed that allows for silica coating without the negative effects of water by generating water during the reaction at high temperatures, ensuring the nanocrystals remain intact.
  • * This innovative method significantly enhances the optical properties of sensitive perovskite nanocrystals and creates a denser silica shell, providing better protection while successfully avoiding water-related damage.
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The interface defects of core-shell colloidal quantum dots (QDs) affect their optoelectronic properties and charge transport characteristics. However, the limited available strategies pose challenges in the comprehensive control of these interface defects. Herein, we introduce a versatile strategy that effectively addresses both surface and interface defects in QDs through simple post-synthesis treatment.

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Owing to outstanding optoelectronic properties, lead halide perovskite nanocrystals (PNCs) are considered promising emitters for next-generation displays. However, the development of pure blue (460-470 nm) perovskite nanocrystal light-emitting diodes (PNC-LEDs), which correspond to the requirements of Rec. 2020 standard, lag far behind that of their green and red counterparts.

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Multicomponent systems consisting of lead halide perovskite nanocrystals (CsPbX-NCs, X = Br, I) grown inside mesoporous silica nanospheres (NSs) with selectively sealed pores combine intense scintillation and strong interaction with ionizing radiation of CsPbX NCs with the chemical robustness in aqueous environment of silica particles, offering potentially promising candidates for enhanced radiotherapy and radio-imaging strategies. We demonstrate that CsPbX NCs boost the generation of singlet oxygen species (O) in water under X-ray irradiation and that the encapsulation into sealed SiO NSs guarantees perfect preservation of the inner NCs after prolonged storage in harsh conditions. We find that the O production is triggered by the electromagnetic shower released by the CsPbX NCs with a striking correlation with the halide composition (I > I Br > Br).

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Article Synopsis
  • Perovskite nanocrystals are gaining attention for their exceptional optical and electronic features, leading to advancements in light-emitting diodes (LEDs) using these materials.
  • Research on semitransparent perovskite LEDs is limited compared to opaque ones, which could hinder their use in future translucent display technologies.
  • The study demonstrated that using a special polymer (PFN) as an electron transport layer significantly improved the efficiency and brightness of both opaque and semitransparent perovskite LEDs, with the semitransparent device achieving an average transmittance of 61% and high brightness levels.
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Plentiful research of InP semiconductor quantum dots (QDs) has been launched over the past few decades for their excellent photoluminescence properties and environmentally friendly characteristics in various applications. However, InP QDs show inferior photostability because they are extremely sensitive to the ambient environment. In this study, we propose a novel method to enhance the photostability of InP/ZnSe/ZnS QDs by doping zirconium into the ZnS layer.

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Sn-based perovskites are the most promising alternative materials for Pb-based perovskites to address the toxicity problem of lead. However, the development of Sn -based perovskites has been hindered by their extreme instability. Here, we synthesized efficient and stable lead-free Cs SnBr perovskite by using SnF as tin source instead of easily oxidized SnBr .

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Artificial intelligence offers new opportunities for translucent displays. However, achieving translucent light-emitting diodes (LEDs) with high efficiency and high color purity remains a challenge. Here, we propose a strategy of using an alkali metal/inert metal (calcium/silver) bilayer metal electrode as a top electrode and perovskite nanocrystals as an emitter layer in the device structure, which allows us to not only fabricate excellent opaque LEDs but also manufacture highly efficient semitransparent LEDs with high color purity, total brightness (over 7000 cd m), total external quantum efficiency (over 12%), and 56% transmittance around 520 nm.

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Article Synopsis
  • Lead halide perovskite nanocrystals have potential for use in next-gen LEDs and displays but suffer from thermal quenching that limits their applications.
  • A new approach involves anion passivation, where specific ions like SO, OH, and F create passivation layers that repair surface defects and stabilize the nanocrystals’ structure.
  • The treated CsPbBr nanocrystals maintain 79% of their light emission intensity at high temperatures (373 K), leading to the development of stable white LED devices that perform well even under thermal stress.
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Deep learning is one of the most advanced forms of machine learning. Most modern deep learning models are based on an artificial neural network, and benchmarking studies reveal that neural networks have produced results comparable to and in some cases superior to human experts. However, the generated neural networks are typically regarded as incomprehensible black-box models, which not only limits their applications, but also hinders testing and verifying.

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