Plasmonic high-entropy carbides

Abstract

Discovering multifunctional materials with tunable plasmonic properties, capable of surviving harsh environments is critical for advanced optical and telecommunication applications. We chose high-entropy transition-metal carbides because of their exceptional thermal, chemical stability, and mechanical properties. By integrating computational thermodynamic disorder modeling and time-dependent density functional theory characterization, we discovered a crossover energy in the infrared and visible range, corresponding to a metal-to-dielectric transition, exploitable for plasmonics. It was also found that the optical response of high-entropy carbides can be largely tuned from the near-IR to visible when changing the transition metal components and their concentration. By monitoring the electronic structures, we suggest rules for optimizing optical properties and designing tailored high-entropy ceramics. Experiments performed on the archetype carbide HfTa4C5 yielded plasmonic properties from room temperature to 1500K. Here we propose plasmonic transition-metal high-entropy carbides as a class of multifunctional materials. Their combination of plasmonic activity, high-hardness, and extraordinary thermal stability will result in yet unexplored applications.

Activating Main-Group Mg Atomic Sites within Tri-s-triazine for Photocatalytic H2O Overall Splitting: Dynamic Mechanism and Performance

“…For natural chlorophyll extracted from green algae, photosynthesis was performed under the same conditions for H 2 generation, but no signal can be detected, which should be attributed to the much different chemical environment of experiments from that in real plants. According to entropy-increasing procedures, photon absorption and conversion in artificial photosynthesis require an entropy-increasing catalytic platform for performance enhancement in light of the second law of thermodynamics. − On one hand, short-wavelength photons will be facilely absorbed and converted into high energy within the entropy-increasing material system; additionally, long-wavelength photons can also be irradiated and activated into energy by coherent vibrations, which is reflected by the apparent quantum efficiency (AQE). AQE values for H 2 O overall splitting into H 2 at wavelengths of 400 and 420 nm over the entropy-increasing Mg- s -triazine-2 system reach 16.25 and 12.37%, respectively, and 7.10 and 3.91% AQE can be achieved under irradiation at 450 and 460 nm, respectively (Figure b), which is nearly a great breakthrough in comparison with other reported materials. − The concrete experiment conditions and calculations are given in eqs S10 and S11.…”

Pulsed Photothermal Heterogeneous Catalysis

“…Conventional, plasmonic metals such as gold and silver melt, deform, and lose function under intense pulsed illumination, even well before their bulk melting point. , Thus, novel robust plasmonic nanomaterials must be developed that can provide access to the high-temperature region where pulsed catalysis becomes most effective. Examples of such materials are thermally robust metal nitrides (e.g., TiN and HfN) , and metal carbides (e.g., HfTa 4 C 5 ) . Further functionalization of these materials with catalytic metals, such as single-atoms catalysts, , could lead to robust photothermal catalysts, especially tailored for pulsed light.…”

“…Examples of such materials are thermally robust metal nitrides (e.g., TiN and HfN) 51 , 52 and metal carbides (e.g., HfTa 4 C 5 ). 53 Further functionalization of these materials with catalytic metals, such as single-atoms catalysts, 54 , 55 could lead to robust photothermal catalysts, especially tailored for pulsed light.…”

Promoting 2D Material Photodetectors by Optical Antennas beyond Noble Metals

“…Profited from the high electrical conductivity, MXenes are well known to be promising material platforms for implementing intense LSPR. Thus far, a variety of MXenes, such as Ti 3 C 2 T x , [194] HfTa 4 C 5 , [195] and Nb 2 CT x , [93] have been proven to possess pronounced plasmonic effect, providing flexible choices for optical engineering research. In addition, MXenes serving as plasmonic optical antennas have been widely exploited in multiple domains including solar cells, [196] water splitting, [197] N 2 photofixation, [198] photonic diodes, [199] biosensing, [200] photothermal desalination, [201] and hydrogen evolution reaction.…”