Nano Research最新文献

Encapsulation is a widely recognized method for enhancing the stability of colloidal quantum dots (CQDs). However, traditional encapsulation methods for solid-state materials expose encapsulated CQDs to risks such as ligand loss and poor dispersion. Additionally, these encapsulated CQDs still face the risk of aging due to surface ligand bond breakage under high-energy radiation. In this study, we found that quantum dots in solution exhibited enhanced ultraviolet (UV) tolerance compared to their counterparts in solid form under an inert atmosphere. We attribute this enhancement to improved ligand retention and self-healing of quantum dots in solution. Herein, we introduce a novel method for fabricating liquid-encapsulated quantum dot (LEQD) color conversion films. This technique leverages the self-healing capability of ligands in liquid-state quantum dots to enhance the UV and thermal stability of the quantum dot color conversion films. Experimental results demonstrate that LEQD films exhibit better resistance to UV radiation and high temperatures than solid-encapsulated quantum dot (SEQD) color conversion films. After 400 h of exposure to 100 mW blue light-emitting device (LED) light at 60 °C and 90% humidity, the brightness of LEQD film retained 90% of its initial level. This liquid-state quantum dot encapsulation approach offers a promising pathway for developing more durable quantum dot color conversion films.

Until now, automation in nanomaterial research has been largely focused on the automated synthesis of engineered nanoparticles (NPs) including the screening of synthesis parameters and the automation of characterization methods such as electron microscopy. Despite the rapidly increasing number of NP samples analyzed due to increasing requirements on NP quality control, increasing safety concerns, and regulatory requirements, automation has not yet been introduced into workflows of analytical methods utilized for screening, monitoring, and quantifying functional groups (FGs) on NPs. To address this gap, we studied the potential of simple automation tools for the quantification of amino surface groups on different types of aminated NPs, varying in size, chemical composition, and optical properties, with the exemplarily chosen sensitive optical fluorescamine (Fluram) assay. This broadly applied, but reportedly error-prone assay, which utilizes a chromogenic reporter, involves multiple pipetting and dilution steps and photometric or fluorometric detection. In this study, we compared the influence of automated and manual pipetting on the results of this assay, which was automatically read out with a microplate reader. Special emphasis was dedicated to parameters like accuracy, consistency, achievable uncertainties, and speed of analysis and to possible interferences from the NPs. Our results highlight the advantages of automated surface FG quantification and the huge potential of automation for nanotechnology. In the future, this will facilitate process and quality control of NP fabrication, surface modification, and stability monitoring and help to produce large data sets for nanomaterial grouping approaches for sustainable and safe-by-design, performance, and risk assessment studies.

Colloidal II–VI nanoplatelets (NPLs) are solution-processable two-dimensional (2D) quantum dots that have vast potential in high-performance optoelectronic applications, including light-emitting diodes, sensors, and lasers. Superior properties, such as ultrapure emission, giant oscillator strength transition, and directional dipoles, have been demonstrated in these NPLs, which can improve the efficiency of light-emitting diodes and lower the threshold of lasers. In this review, we present an overview of the current progress and propose perspectives on the most well-studied II–VI NPLs that are suitable for the optoelectronic applications. We emphasize that the control of the symmetrical shell growth of NPLs is critical for the practical utilization of the advantages of NPLs in these devices.

Silver chalcogenides (Ag₂E; E = S, Se, or Te) quantum dots (QDs) have emerged as promising candidates for near-infrared (NIR) applications. However, their narrow bandgap and small exciton Bohr radius render the optical properties of Ag₂E QDs highly sensitive to surface and size variations. Moreover, the propensity for the formation of silver impurities and their low solubility product constants pose challenges in their controllable synthesis. Recent advancements have deepened our understanding of the relationship between the multi-hierarchical structure of Ag₂E QDs and their optical properties. Through rational design and precise structural regulation, the performance of Ag₂E QDs has been significantly enhanced across various applications. This review provides a comprehensive overview of historical and current progress in the synthesis and structural regulation of Ag₂E QDs, encompassing aspects such as size control, crystal structure engineering, and surface/interface engineering. Additionally, it discusses outstanding challenges and potential opportunities in this field. The aim of this review is to promote the custom synthesis of Ag₂E QDs for applications in biological imaging, and optoelectronics applications.

With the accelerating development of electronic technology, how to effectively eliminate electromagnetic radiation pollution has become a critical issue. Electromagnetic wave (EMW) absorption materials have an irreplaceable position in the field of military stealth as well as in the field of electromagnetic pollution control. In order to cope with the complicated electromagnetic environment, the design of multifunctional and multiband high-efficiency EMW absorbers remains a daunting challenge. In this work, a hierarchical porous molybdenum carbide matrix with a three-dimensional porous structure was designed by salt melt synthesis (SMS) strategy. Furthermore, the relationship between the structure and the impedance matching performance was explored by stepwise modification via ultrathin layered MoS₂ nanoflakes. Analysis indicates that the extent of modification of hierarchical porous molybdenum carbide by MoS₂ nanoflakes modulates the dielectric performance due to differences in morphology and the introduction of heterogeneous structures, along with a dramatic impact on the impedance matching performance. In particular, the prepared MS/MC/PNC-2 composite exhibits a reflection loss (RL) of -55.30 dB at 2.4 mm, and an ultra-broad effective absorption bandwidth (EAB) of 7.60 GHz is obtained at 2.0 mm. The coordination of structure and component enables the absorber to exhibit strong absorption, wide bandwidth, thin thickness, and multi-band absorption characteristics. Noticeably, the effective absorption performance in the broadband for X and Ku is also satisfying, as well as possessing moderate marine anti-corrosion performance. This study contributes to an in-depth understanding of the relationship between impedance matching and EMW absorber performance and provides a reference for the design of multifunctional, multiband microwave absorbing materials.