Metal chalcogenide/oxide-based quantum dots decorated functional materials for energy-related applications: Synthesis and preservation

High-Reliability Perovskite Quantum Dots Using Atomic Layer Deposition Passivation for Novel Photonic Applications

In this study, we propose highly stable perovskite quantum dots (PQDs) coated with Al₂O₃ using atomic layer deposition (ALD) passivation technology. This passivation layer effectively protects the QDs from moisture infiltration and oxidation as well as from high temperatures and any changes in the material characteristics. They exhibit excellent wavelength stability and reliability in terms of current variation tests, long-term light aging tests, and temperature/humidity tests (60°/90%). A white-light system has been fabricated by integrating a micro-LED and red phosphor exhibiting a high data transmission rate of 1 Gbit/s. These results suggest that PeQDs treated with ALD passivation protection offer promising prospects in full-color micro-displays and high-speed visible-light communication (VLC) applications.

Metallic Co and crystalline Co-Mo oxides supported on graphite felt for bifunctional electrocatalytic hydrogen evolution and urea oxidation

Oxygen evolution reaction (OER) and urea oxidation reaction (UOR) play important roles in the field of hydrogen energy preparation and pollution treatment. In this work, by merging bimetallic Co-Mo oxides with metallic Co on the graphite felt (GF), we effectively manufacture a 3D bifunctional and highly efficient electrocatalyst (CoMoO@Co/GF) with multi-site functionality for the simultaneous reduction of water and the oxidation of urea in an alkaline medium. The presence of metallic Co causes Co-Mo oxides to evolve from amorphous to crystalline structures. The coupling interface produced between metallic Co and Co-Mo oxides is proven to facilitate electron transport in addition to extensively accessible and highly electroactive Co-Mo oxide nanoflower architecture. The experimental results reveal that the overpotentials for OER and UOR in the CoMoO@Co/GF electrode require only 269 and 115 mV to obtain a current density of 10 mA cm^-2, respectively. Furthermore, with the aid of urea, the overpotential for HER at the current density of 10 mA cm^-2 is lowered to 155 mV. Most notably, the constructed CoMoO@Co/GF-based electrolytic cell only requires a 1.5 V dry battery to achieve effective H₂ evolution and noteworthy stability, outperforming the commercial catalyst-based device and many previous results. The combination of experiments and theoretical calculations further clarifies the active sites in the catalyst. What's more, the pathway of electron transfer in the catalytic process is defined.

Development of QDs-based nanosensors for heavy metal detection: A review on transducer principles and in-situ detection

Heavy metal pollution has severe threats to the ecological environment and human health. Thus, it is urgent to achieve the rapid, selective, sensitive and portable detection of heavy metal ions. To overcome the defects of traditional methods such as time-consuming, low sensitivity, high cost and complicated operation, QDs (Quantum dots)-based nanomaterials have been used in sensors to significantly improve the sensing performance. Due to their excellent physicochemical properties, high specific surface area, high adsorption and reactive capacity, nanomaterials could act as potential probes or offer enhanced sensitivity and create a promising nanosensors platform. In this review, the rapidly advancing types of QDs for heavy metal ions detection are first summarized. Modified with ligands, nanomaterials, or biomaterials, QDs are assembled on sensors by the interaction of electrostatic adsorption, chemical bonding, steric hindrance, and base-pairing. The stability of QDs-based nanosensors is improved by doping the elements to QDs, providing the reference substance, optimizing the assemble strategies and so on. Then, according to transducer principles, the two most typical sensor categories based on QDs: optical and electrochemical sensors are highlighted to be discussed. In the meanwhile, portable devices combining with QDs to adapt the practical detection in complex situations are summarized. The deficiencies and future challenges of QDs in toxicity, specificity, portability, multi-metal co-detection and degradation during the detection are also pointed out. In the end, the development trends of QDs-based nanosensors for heavy metal ions detection are discussed. This review presents an overall understanding, recent advances, current challenges and future outlook of QDs-based nanosensors for heavy metal detection.