Chemistry of Materials最新文献

Luminescence thermometry is a highly promising technique for remotely measuring temperature. Nowadays, this method is unrivaled, considering its methodology and high potential for application. However, expanding the operating range of luminescent thermometers is still a challenge. We have successfully demonstrated that by introducing just one dopant, Pr³⁺, to garnet hosts, we can create a luminescence thermometer that operates in an impressive range of 13–1025 K. Our paper also presents a thorough analysis of the Pr³⁺ location in Sr₃Y₂Ge₃O₁₂ and Sr₃Sc₂Ge₃O₁₂ garnet hosts, revealing three Pr sites in the former and two in the latter, which has not been previously reported in these phosphors. By using 5d → 4f luminescence below room temperature, we obtained relative thermal sensitivities reaching ∼6%/K. By using the luminescence intensity ratio of the 4f → 4f transitions, we achieved an operating range of 13–1025 K with relative thermal sensitivity ranging from 0.1 to 0.8%/K. Finally, the small and uniform size of the particles, about 150 nm in diameter, is attractive for high spatial resolution applications.

Introducing polyoxometalates (POMs) as redox mediators can decouple direct electrochemical reactions into surface-homogeneous conversion steps. And the formed redox catalysis is beneficial to achieve more efficient hydrogenation of nitrobenzene (Ph-NO₂) to aniline (Ph-NH₂) at low overpotentials. Notably, the redox potentials of POMs can adjust the energy barrier of the hydrogenation reaction, thus improving conversion efficiency. In particular, by using phosphotungstic acid ({PW₁₂}) as the redox mediator, the potential of the hydrogenation of Ph-NO₂ to Ph-NH₂ was improved to 0.04 V vs RHE with a very high k_app of 0.0339 min^–1. This indicates its superior kinetic performance over that of most previously reported electrocatalysts. In addition, through comparative mechanistic studies of electrocatalysis and redox mediator catalysis, EC-SERS revealed the preferential adsorption of mediator molecules and their direct interactions with intermediates. This work is significant to a deep understanding of the mechanistic behaviors and potential tuning effects of redox mediators, which will help to develop more efficient mediators for the hydrogenation of Ph-NO₂.

Achieving atomic-scale precise control over material layering is critical for the development of future semiconductor technology. Area-selective deposition (ASD) has emerged as an indispensable tool for crafting semiconductor components and structures via bottom-up pattern transfer. Ruthenium has attracted significant interest as a low-resistivity conducting material for next-generation interconnect technology. However, the oxidative counter-reactants such as O₂ often used for atomic layer deposition (ALD) of metallic Ru films result in a considerable increase in contact resistance because of substrate oxidation, limiting the applications of both ALD and ASD of Ru. In this study, Ru ASD is demonstrated using two-step ALD with the sequential use of H₂ and O₂ as counter-reactants and dimethylamino-trimethylsilane (DMATMS) as a precursor inhibitor. Both theoretical and experimental results demonstrate that in the two-step Ru ALD, the oxide layer can be eliminated via the reduction of the oxidized substrate metal surface by the H₂ counter-reactant. This mechanism simultaneously facilitates the adsorption of the Ru precursor (tricarbonyl-(trimethylenemethane)-ruthenium) and removal of the surface oxide layer. Consequently, Ru growth is suppressed on the DMATMS-inhibited SiO₂ surface during ASD, enabling exclusive deposition of Ru on the Mo surface. The currently proposed Ru ASD scheme using two-step ALD is highly promising for driving advancements in interconnect technology for commercial applications.

Noble metal nanoparticles, particularly gold and silver nanoparticles, have garnered significant attention due to their ability to manipulate light at the nanoscale through their localized surface plasmon resonance (LSPR). While their LSPRs below 1100 nm were extensively exploited in a wide range of applications, their potential in the near-infrared (NIR) region, crucial for optical communication and sensing, remains relatively underexplored. One primary reason is likely the limited strategies available to obtain highly stable plasmonic nanoparticles with tailored optical properties in the NIR region. Herein, we synthesized AuAg nanorattles (NRTs) with tailored and narrow plasmonic responses ranging from 1000 to 3000 nm. Additionally, we performed comprehensive characterization, employing advanced electron microscopy and various spectroscopic techniques, coupled with finite difference time domain (FDTD) simulations, to elucidate their optical properties. Notably, we unveiled the main external and internal LSPR modes by combining electron energy-loss spectroscopy (EELS) with surface-enhanced Raman scattering (SERS). Furthermore, we demonstrated through surface-enhanced infrared absorption spectroscopy (SEIRA) that the NRTs can significantly enhance the infrared signals of a model molecule. This study not only reports the synthesis of plasmonic NRTs with tunable LSPRs over the entire NIR range but also demonstrates their potential for NIR sensing and optical communication.