Rapid progress has taken place in the generation and application of femtosecond optical pulses. The impact of these developments is being felt in a broad range of scientific fields, including physics, chemistry, biology, and engineering. These rapidly evolving techniques have been applied to such diverse problems as phase transitions in highly excited semiconductors, molecular photofragment spectroscopy, impulsive phonon generation in solids, and optical radar ranging through biological tissue.
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http://dx.doi.org/10.1126/science.233.4770.1276 | DOI Listing |
Metal halide perovskites have unique luminescent properties that make them an attractive alternative for high quality light-emitting devices. However, the poor stability of perovskites with many defects and the long cycle time for the preparation of perovskite nanocomposites have hindered their production and application. Here, we prepared the perovskite mesostructures by embedding MAPbBr nanocrystals in the mesopores on the surface of silica nanospheres and mixing the nanospheres with silver nanowires and poly(methyl methacrylate) (PMMA), and further explored their optical properties.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
August 2024
Compressed ultrafast photography (CUP) is a high-speed imaging technique with a frame rate of up to ten trillion frames per second (fps) and a sequence depth of hundreds of frames. This technique is a powerful tool for investigating ultrafast processes. However, since the reconstruction process is an ill-posed problem, the image reconstruction will be more difficult with the increase of the number of reconstruction frames and the number of pixels of each reconstruction frame.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Science Institute and Faculty of Physical Sciences, University of Iceland, Reykjavík, Iceland.
Understanding the ultrafast vibrational relaxation following photoexcitation of molecules in a condensed phase is essential to predict the outcome and improve the efficiency of photoinduced molecular processes. Here, the vibrational decoherence and energy relaxation of a binuclear complex, [Pt2(P2O5H2)4]4- (PtPOP), upon electronic excitation in liquid water and acetonitrile are investigated through direct adiabatic dynamics simulations. A quantum mechanics/molecular mechanics (QM/MM) scheme is used where the excited state of the complex is modeled with orbital-optimized density functional calculations while solvent molecules are described using potential energy functions.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Institute of Physics, Lodz University of Technology, ul. Wólczańska 217/221, 93-590 Łódź, Poland.
Photocycloreversion reactions of three diarylethene derivatives whose structures differ only in the placement of two sulfur atoms in the cyclopentene rings are investigated. Despite the minuscule differences between the molecules, both the yields and times of the photoreactions vary considerably. Using UV-vis and infrared femtosecond spectroscopy and quantum chemical dynamics simulations, we elucidate the relationships among the quantum yield, electronic and vibrational relaxation time, and structural properties of the dithienylethene photoswitches.
View Article and Find Full Text PDFACS Sens
January 2025
Department of Physics, Chungnam National University, 99 Daehak-road, Yuseong-gu, Daejeon 34134, Republic of Korea.
Rational design of heterostructure (HS)-based surface acoustic wave (SAW) smart gas sensors for efficient and accurate subppm level ammonia (NH) detection at room temperature (RT) is of great significance in environmental protection and human safety. This study introduced a novel HS composed of an AlN-based SAW resonator and CuO nanoparticles (NPs) as a chemical interface for NH detection at RT (∼26 °C). The structural, morphological, and chemical compositions were detailly investigated, which demonstrates that the CuO/AlN HS was successfully formed via interfacial modulation.
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