Singlet oxygen ( 1 O 2 ) in the chemiluminescence (CL) of luminol has been rarely involved. In this work, graphene oxide (GO) was prepared and at first found to enhance the CL of luminol-H 2 O 2 system in a weakly alkaline medium mainly through the intermediate of 1 O 2 , which was greatly different from the traditional catalyst in such CL system that occurred in a strongly basic medium through the intermediates such as superoxide anion radical (O 2 •−) and hydroxyl radical (OH•). With the aid of CL spectral, UV−visible absorption spectral, and electron spin resonance (ESR) spectral measurements and investigations on the effects of various free radical scavengers on the GO-enhanced luminol CL, we identified the acceleration role of GO played in the electron-transfer processes and efficient catalysis on the decomposition of H 2 O 2 , generating a high yield of 1 O 2 on the surface of GO. The resulted 1 O 2 then reacted with luminol, producing an endoperoxide, which decomposed to the excited-state 3-aminophthalate anions (3-APA*), giving rise to light emission with the maximum wavelength at 440 nm. As a result, this 1 O 2 -induced luminol CL, owing to the catalysis by GO, could have six-fold enhancement compared with that in the absence of GO. These investigations could be further extended to the use of GO as an amplified label for the CL determinations of H 2 O 2 and glucose. The significant features of this GO-catalyzed luminol CL may open up new opportunities for its potential applications in a wide range of fields.
A resonant metasurface with high quality factor can not only localize light at the nanoscale but also manipulate the far-field radiation. In this work, we experimentally demonstrate an active Fano-resonant metasurface that combines an asymmetric silicon nanorod array with embedded germanium quantum dots. The collective resonance of the nanorods results in strong near-field confinement, and the nanorods also lead to directional emission. This gives rise to 3 orders of magnitude enhancement of the photoluminescence intensity with respect to the unpatterned area. Besides, due to the symmetry-breaking property of the structure, the light emission is of specific polarization. Moreover, by varying the geometric parameters of the nanorods, different resonances are spectrally overlapped, which can be utilized to manipulate the far-field radiation pattern. The metasurface shows enormous potential in manipulating light emission and provides a route for high-directionality, high-efficiency LEDs and potentially functional dielectric metasurface lasers.
Owing to the unique advantages of photoacoustic imaging (PAI) and photothermal therapy (PTT) conducted over the near‐infrared‐II (NIR‐II) window, the development of high‐efficiency optical agents with NIR‐II light responsiveness is of great significance. Despite the diversity of optical agents developed for NIR‐II PAI and PTT, most of them are based on inorganic nanomaterials and small molecular dyes, whose biosafety and photostability need to be further assessed, respectively. Organic semiconducting macromolecular dyes (OSMDs) featuring a large semiconducting backbone are becoming alternative candidates for NIR‐II PAI and PTT owing to their reliable biocompatibility, durable photostability, and ideal photothermal conversion capability. This paper reviews the current progress of OSMD‐based PAI and PTT in the NIR‐II optical window. The three main types of OSMDs with different skeleton architectures are introduced, and their applications for NIR‐II PAI (tumor imaging, stem cell tracking, and vasculature imaging) and PTT (tumor ablation) are described. Viable strategies for further improving the NIR‐II PAI performance of OSMDs are discussed. Finally, some major issues faced by OSMDs in NIR‐II PAI and PTT are raised, and the future development directions of OSMDs are analyzed.
Sulfur hexafluoride (SF6) gas has been used in large-scale electrical equipment, because of its excellent high-voltage dielectric strength. However, SF6 has been identified as a greenhouse gas, because of its high global warming potential (GWP) and extended lifetime in the atmosphere. Based on theoretical calculations, trifluoromethanesulfonyl fluoride (CF3SO2F) is a relatively eco-friendly gas with a lower GWP than that of SF6, and the electrical performance of CF3SO2F is also superior to that of SF6. A new procedure to synthesize CF3SO2F gas is presented for application in high-voltage insulation. An AC breakdown voltage test involved mixing CF3SO2F with CO2 and N2 to obtain insulation data. The stability of CF3SO2F was shown by self-recoverability tests and decomposition product analysis after breakdown, and the results show no harmful or flammable and explosive byproduct that would have a negative climate impact. These results demonstrate that CF3SO2F gas has great potential as a new insulating gas with great dielectric strength.
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