Plasmonic hot carriers have been recently identified as key elements for photocatalysis at visible wavelengths. The possibility to transfer energy between metal plasmonic nanoparticles and nearby molecules depends not only on carrier generation and collection efficiencies but also on their energy at the metal-molecule interface. Here an energy screening study was performed by monitoring the aniline electro-polymerization reaction via an illuminated 80 nm gold nanoparticle. Our results show that plasmon excitation reduces the energy required to start the polymerization reaction as much as 0.24 eV. Three possible photocatalytic mechanisms were explored: the enhanced near field of the illuminated particle, the temperature increase at the metal-liquid interface, and the excited electron-hole pairs. This last phenomenon is found to be the one contributing most prominently to the observed energy reduction.
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http://dx.doi.org/10.1021/acs.nanolett.8b04950 | DOI Listing |
Nanotechnology
January 2025
Department of Electrical and Computer Engineering, Nazarbayev University, Nazarbayev University, Astana, Kazakhstan, Astana, 010000, KAZAKHSTAN.
Non-equilibrium molecular dynamics (NEMD) simulations reveal the existence of a spontaneous heat current (SHC) in the absence of a temperature gradient and demonstrate ultra-high thermal rectification in asymmetric trapezoid-shaped graphene. These unique properties have potential applications in power generation and thermal circuits, functioning as thermal diodes. Our findings also show the presence of negative and zero thermal conductivity in this system.
View Article and Find Full Text PDFBiomed Phys Eng Express
January 2025
Department of Medical Physics, Osaka Heavy Ion Therapy Center, Otemae, Chuo-ku, Osaka, Osaka, 5400008, JAPAN.
Objective Applying carbon ion beams, which have high linear energy transfer and low scatter within the human body, to Spatially Fractionated Radiation Therapy (SFRT) could benefit the treatment of deep-seated or radioresistant tumors. This study aims to simulate the dose distributions of spatially fractionated beams (SFB) to accurately determine the delivered dose and model the cell survival rate following SFB irradiation. Approach Dose distributions of carbon ion beams are calculated using the Triple Gaussian Model.
View Article and Find Full Text PDFEnviron Toxicol Chem
January 2025
School of Environment and Energy, South China University of Technology, Guangzhou, PR China.
As a representative agent of bicyclic antidepressants, venlafaxine (VEN) has become widely used worldwide and is frequently detected in surface waters with concentrations ranging from ng/L to µg/L. To evaluate the toxicological effects of such medications on aquatic species, studies on environmentally relevant concentrations are essential. Zebrafish were used as a model organism to assess growth and development in larvae and examine tissue accumulation, oxidative stress, and DNA methylation in adults.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, School of Chemistry and Life Resources, Renmin University of China, Beijing 100872, P. R. China.
Chlorophyll (Chl) is the most abundant light-harvesting pigment of oxygenic photosynthetic organisms; however, the Q-band energetics and relaxation dynamics remain unclear. In this work, we have applied femtosecond time-resolved (-TA) absorption spectroscopy in 430-1,700 nm to Chls and in diluted pyridine solutions under selective optical excitation within their Q-bands. The results revealed distinct near-infrared absorption features of the B ← Q and B ← Q transitions in 930-1,700 nm, which together with the steady-state absorption in 400-700 nm unveiled the Q-state energy that lies 1,000 ± 400 and 600 ± 400 cm above the Q-state for Chls and , respectively.
View Article and Find Full Text PDFNano Lett
January 2025
Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720, United States.
Ultrafast near-field optical nanoscopy has emerged as a powerful platform to characterize low-dimensional materials. While analytical and numerical models have been established to account for photoexcited carrier dynamics, quantitative evaluation of the associated pulsed laser heating remains elusive. Here, we decouple the photocarrier density and temperature increase in near-field nanoscopy by integrating the two-temperature model (TTM) with finite-difference time-domain (FDTD) simulations.
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