Near-infrared II (NIR-II) fluorophores possess transformative potential for biomedical applications. This review systematically summarizes the advances over past five years in organic small-molecule NIR-II fluorophores for phototheranostics, including cyanine, BODIPY, benzobisthiadiazole, xanthene, cyano-based derivatives and small-molecule metal complexes, providing insights into further innovation and facilitating clinical translation.

Seoul National University College of Engineering announced that a research team led by Prof. Sung-Hoon Ahn of the Department of Mechanical Engineering has developed, for the first time in the world, an “interference acoustic band-pass filter” capable of selectively filtering and amplifying specific frequencies without the use of electronic circuits.

By utilizing a single microphone and an interference-based metamaterial structure, the researchers have demonstrated a technology that enables selective listening to desired frequencies, opening new possibilities for diagnosing machine failures in high-noise industrial environments.

The research findings were published this month in Mechanical Systems and Signal Processing, an international journal in the field of mechanical engineering.

Proton exchange membrane water electrolyzers (PEMWEs) are regarded as a potential technology to generate green hydrogen as a renewable energy. Among the benchmarked electrocatalysts used in PEMWEs, IrO₂ exhibits a high stability in a harsh acidic environment but a relatively low activity. It generally requires an Ir loading as high as 2-4 mg_Ir cm^-2 to reach reasonable performance, which however, is uneconomical for such a noble metal for practical application of PEMWEs. As a result, it is urged to reduce iridium loading in PEMWEs while maintain high catalytic performance.

Laser ablation was employed to create nanotwinned structures in platinum-cobalt (PtCo) nanoparticles, which led to improved stability and mass activity during proton-exchange membrane fuel cell (PEMFC) tests, surpassing U.S. Department of Energy (DOE) standards. The process involves particle migration and clustering under laser exposure, followed by rapid cooling that encourages the development of twinning structures; the presence of cobalt decreases stacking-fault energy, further supporting twin formation. Additionally, laser ablation offers fast and energy-efficient processing, making it possible to scale up catalyst production and quickly investigate various metastable alloys.

Antimony sulfide (Sb₂S₃) is a competitive photovoltaic material, especially for tandem solar cells. However, the quasi-intrinsic carrier concentration and deep work function of Sb₂S₃ cause serious extraction problem at Sb₂S₃/hole-transport-layer (HTL) interface. In this study, Professor Tang Jiang's Research Group at Huazhong University of Science and Technology proposed an efficient strategy to modify the Sb₂S₃/HTL interface by lead chloride (PbCl₂) post-treatment. Their results demonstrated that Cl can passivate the defect of V_S and Sb_S, and Pb enabled effective p-type doping at the Sb₂S₃ interface with the help of V_S removal. And the synergistic effect of Pb and Cl elements matched well with HTL energy level, facilitated hole extraction and enhanced the interface conductivity. By employing PbCl₂ treatment, the resulting devices obtained a high fill factor (FF) of 66.02%, and a top power conversion efficiency (PCE) of 8.05%.

Friction and wear are the ‘energy drains’ and ‘lifespan terminators’ in the mechanical world. Conventional lubricant additives, such as the well-known zinc dialkyldithiophosphate (ZDDP), are highly effective but contain environmentally unfriendly elements like sulfur and phosphorus. Moreover, their lubrication performance is significantly reduced on ‘soft metals’ such as aluminum alloys and stainless steel. Titanium dioxide (TiO₂) nanocrystals, with their controllable morphology and eco-friendly properties, are considered ideal candidates as next-generation lubricant additives.