scholarly journals Multimodal Plasmonic Hybrids: Efficient and Selective Photocatalysts

2021 ◽  
Author(s):  
Yoel Negrín-Montecelo ◽  
Xiang-Tian Kong ◽  
Lucas Besteiro ◽  
Enrique Carbo-Argibay ◽  
Zhiming Wang ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Near Field ◽  
Field Enhancement ◽  
Test System ◽  
Plasmonic Nanostructures ◽  
Energy Transfer Mechanism ◽  
Hot Electron ◽  
Synthetic Strategy ◽  
Hot Electron Injection ◽  
Joint Contribution

Important efforts are currently under way in order to implement plasmonic phenomena in the growing field of photocatalysis, striving for improved efficiency and reaction selectivity. A significant fraction of such efforts have been focused on distinguishing, understanding and enhancing specific energy transfer mechanisms from plasmonic nanostructures to their environment. Herein we report a synthetic strategy that brings together two of the main physical mechanisms driving plasmonic photocatalysis into an engineered system by rationally combining the photochemical features of energetic charge carriers and the electromagnetic field enhancement inherent to the plasmonic excitation. We do so by creating hybrid photocatalysts that integrate multiple plasmonic resonators in a single entity, controlling their joint contribution through spectral separation and differential surface functionalization. This strategy allows us to study the combination of different photosensitization mechanisms when activated simultaneously. Our results show that hot electron injection can be combined with an energy transfer process mediated by near-field interaction, leading to a significant increase of the final photocatalytic response of the material. In this manner, we overcome the limitations that hinder photocatalysis driven only by a single energy transfer mechanism, and move the field of plasmonic photocatalysis closer to energy-efficient applications. Furthermore, our multimodal hybrids offer a test system to probe the properties of the two targeted mechanisms and open the door to wavelength-selective photocatalysis and novel tandem reactions.

scholarly journals Prospects and applications of plasmon-exciton interactions in the near-field regime

Nanophotonics ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 613-628 ◽  
Author(s):  
Natalia Kholmicheva ◽  
Luis Royo Romero ◽  
James Cassidy ◽  
Mikhail Zamkov
Keyword(s):  
Energy Transfer ◽  
Near Field ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Dipole Interaction ◽  
Field Energy ◽  
Metal Nanostructures ◽  
Hot Electron ◽  
Hot Electron Injection ◽  
Light Amplification

AbstractPlasmonics is a rapidly developing field at the boundary of fundamental sciences and device engineering, which exploits the ability of metal nanostructures to concentrate electromagnetic radiation. The principal challenge lies in achieving an efficient conversion of the plasmon-concentrated field into some form of useful energy. To date, a substantial progress has been made within the scientific community in identifying the major pathways of the plasmon energy conversion. Strategies based on the hot electron injection and the near-field energy transfer have already shown promise in a number of proof-of-principle plasmonic architectures. Nevertheless, there are several fundamental questions that need to be addressed in the future to facilitate the transition of plasmonics to a variety of applications in both light amplification and optical detection. Of particular interest is a plasmon-induced resonance energy transfer (PIRET) process that couples the plasmon evanescent field to a semiconductor absorber via dipole-dipole interaction. This relatively unexplored mechanism has emerged as a promising light conversion strategy in the areas of photovoltaics and photocatalysis and represents the main focus of the present minireview. Along these lines, we highlight the key advances in this area and review some of the challenges associated with applications of the PIRET mechanism in nanostructured systems.

scholarly journals Metal–dielectric hybrid nanoantennas for efficient frequency conversion at the anapole mode

2018 ◽  
Vol 9 ◽  
pp. 2306-2314 ◽  
Author(s):  
Valerio F Gili ◽  
Lavinia Ghirardini ◽  
Davide Rocco ◽  
Giuseppe Marino ◽  
Ivan Favero ◽  
...  
Keyword(s):  
Frequency Conversion ◽  
Near Infrared ◽  
Strong Field ◽  
Second Harmonic ◽  
Near Field ◽  
Field Enhancement ◽  
High Refractive Index ◽  
Plasmonic Nanostructures ◽  
Ohmic Losses ◽  
Order Of Magnitude

Background: Dielectric nanoantennas have recently emerged as an alternative solution to plasmonics for nonlinear light manipulation at the nanoscale, thanks to the magnetic and electric resonances, the strong nonlinearities, and the low ohmic losses characterizing high refractive-index materials in the visible/near-infrared (NIR) region of the spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near-field enhancement, which are characteristic of this mode. Plasmonic nanostructures, on the other hand, remain the most promising solution to achieve strong local field confinement, especially in the NIR, where metals such as gold display relatively low losses. Results: We present a nonlinear hybrid antenna based on an AlGaAs nanopillar surrounded by a gold ring, which merges in a single platform the strong field confinement typically produced by plasmonic antennas with the high nonlinearity and low loss characteristics of dielectric nanoantennas. This platform allows enhancing the coupling of light to the nanopillar at coincidence with the anapole mode, hence boosting both second- and third-harmonic generation conversion efficiencies. More than one order of magnitude enhancement factors are measured for both processes with respect to the isolated structure. Conclusion: The present results reveal the possibility to achieve tuneable metamixers and higher resolution in nonlinear sensing and spectroscopy, by means of improved both pump coupling and emission efficiency due to the excitation of the anapole mode enhanced by the plasmonic nanoantenna.

Controlling Plasmon-Induced Resonance Energy Transfer and Hot Electron Injection Processes in Metal@TiO2Core–Shell Nanoparticles

2015 ◽  
Vol 119 (28) ◽  
pp. 16239-16244 ◽  
Author(s):  
Scott K. Cushing ◽  
Jiangtian Li ◽  
Joeseph Bright ◽  
Brandon T. Yost ◽  
Peng Zheng ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Electron Injection ◽  
Hot Electron ◽  
Shell Nanoparticles ◽  
Hot Electron Injection

scholarly journals On the Large Near-Field Enhancement on Nanocolumnar Gold Substrates

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pablo Díaz-Núñez ◽  
José Miguel García-Martín ◽  
María Ujué González ◽  
Raquel González-Arrabal ◽  
Antonio Rivera ◽  
...  
Keyword(s):  
Hot Spots ◽  
Near Field ◽  
Broad Band ◽  
Field Enhancement ◽  
Surface Enhanced Raman Spectroscopy ◽  
Plasmonic Nanostructures ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Nanostructured Gold ◽  
High Roughness

Abstract One of the most important and distinctive features of plasmonic nanostructures is their ability to confine large electromagnetic fields on nanometric volumes; i.e., the so-called hot spots. The generation, control and characterization of the hot spots are fundamental for several applications, like surface-enhanced spectroscopies. In this work, we characterize the near-field distribution and enhancement of nanostructured gold thin films fabricated by glancing angle deposition magnetron sputtering. These films are composed of columnar nanostructures with high roughness and high density of inter-columnar gaps, where the electromagnetic radiation can be confined, generating hot spots. As expected, the hot spots are localized in the gaps between adjacent nanocolumns and we use scattering-type scanning near-field optical microscopy to image their distribution over the surface of the samples. The experimental results are compared with finite-difference time-domain simulations, finding an excellent agreement between them. The spectral dependence of the field-enhancement is also studied with the simulations, together with surface-enhanced Raman spectroscopy at different excitation wavelengths in the visible-NIR range, proving a broad-band response of the substrates. These findings may result in interesting applications in the field of surface-enhanced optical spectroscopies or sensing.

scholarly journals Light-induced symmetry breaking for enhancing second-harmonic generation from an ultrathin plasmonic nanocavity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Guang-Can Li ◽  
Dangyuan Lei ◽  
Meng Qiu ◽  
Wei Jin ◽  
Sheng Lan ◽  
...  
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Noble Metals ◽  
Second Harmonic ◽  
Near Field ◽  
Field Enhancement ◽  
Plasmonic Nanostructures ◽  
Far Field ◽  
Field Amplification ◽  
Gold Nanosphere

AbstractEfficient frequency up-conversion of coherent light at the nanoscale is highly demanded for a variety of modern photonic applications, but it remains challenging in nanophotonics. Surface second-order nonlinearity of noble metals can be significantly boosted up by plasmon-induced field enhancement, however the related far-field second-harmonic generation (SHG) may also be quenched in highly symmetric plasmonic nanostructures despite huge near-field amplification. Here, we demonstrate that the SHG from a single gold nanosphere is significantly enhanced when tightly coupled to a metal film, even in the absence of a plasmon resonance at the SH frequency. The light-induced electromagnetic asymmetry in the nanogap junction efficiently suppresses the cancelling of locally generated SHG fields and the SH emission is further amplified through preferential coupling to the bright, bonding dipolar resonance mode of the nanocavity. The far-field SHG conversion efficiency of up to $$3.56\times 10^{-7}$$ 3.56 × 1 0 − 7 W−1 is demonstrated from a single gold nanosphere of 100 nm diameter, two orders of magnitude higher than for complex double-resonant plasmonic nanostructures. Such highly efficient SHG from a metal nanocavity also constitutes an ultrasensitive nonlinear nanoprobe to map the distribution of longitudinal vectorial light fields in nanophotonic systems.

scholarly journals Understanding the Mechanism of Plasmon-Driven Water Splitting: Hot Electron Injection and Near Field Enhancement Effects

2021 ◽  
Author(s):  
Jiaquan Huang ◽  
Xinyi Zhao ◽  
Xunkun Huang ◽  
Wanzhen Liang
Keyword(s):  
Water Splitting ◽  
Chemical Reactions ◽  
Reaction Rate ◽  
Near Field ◽  
Electron Injection ◽  
Model Systems ◽  
Au Nanoparticle ◽  
Hot Electron ◽  
Hot Carriers ◽  
Hot Electron Injection

Utilizing plasmon-generated hot carriers to drive chemical reactions has currently become an active area of research in solar photocatalysis at the nanoscale. However, the mechanism underlying exact transfer and the generation dynamics of hot carriers, and the strategies used to further improve the quantum efficiency of the photocatalytic reaction still deserve a further look. In this work, we perform a nonadiabatic excited-state dynamics study to depict the correlation between the reaction rate of plasmon-driven water splitting (PDWS) and the sizes of gold particles, the incident light frequency and intensity, and the near-field's spatial distribution. Four model systems, \ce{H2O} and \ce{Au20}@\ce{H2O} separately interacting with the laser field and the near field generated by the Au nanoparticle (NP) with a few nanometers in size, have been investigated. Our simulated results clearly unveil the mechanism of PDWS and hot-electron injection in a Schottky-free junction: the electrons populated on the antibonding orbitals of \ce{H2O} are mandatory to drive the \ce{OH} bond breaking and the strong orbital hybridization between \ce{Au20} and \ce{H2O} creates the condition for direct electron injection. We further find that the linear dependence of the reaction rate and the field amplitude only holds at a relatively weak field and it breaks down when the second {\ce{OH}} bond begins to dissociate and field-induced water fragmenting at a very intensive field, and that with the guarantee of electron injection, the water splitting rate increases with the increase of NP's size. This study will be helpful for further improving the efficiency of the photochemical reactions involving the plasmon-generated hot carriers and expanding the applications of hot carriers in varieties of chemical reactions.

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