Near-Field Photonics

**Session chair:** Joanna Atkin
 
 **Title:** Multimodal Hyperspectral Nanoimaging
 **Speaker:** [Yohannes Abate](https://underline.io/speakers/127520-yohannes-abate)
 **Affiliation:** University of Georgia, USA
 
 **Abstract:** 
 Single-layer heterostructures exhibit striking quasiparticle properties and many-body interaction effects that hold promise for a range of applications. However, their properties can be altered by intrinsic and extrinsic defects, thus diminishing their applicability. Therefore, it is of paramount importance to identify defects and understand 2D materials’ degradation over time using advanced multimodal imaging techniques. Here we implemented a liquid-phase precursor approach to synthesize 2D in-plane MoS2–WS2 heterostructures exhibiting nanoscale alloyed interfaces and map exotic interface effects during photodegradation using a combination of hyperspectral tip-enhanced photoluminescence and Raman and near-field nanoscopy. Surprisingly, 2D alloyed regions exhibit thermal and photodegradation stability providing protection against oxidation. Coupled with surface and interface strain, 2D alloy regions create stable localized potential wells that concentrate excitonic species via a charge carrier funneling effect. These results demonstrate that 2D alloys can withstand extreme degradation effects over time and could enable stable 2D device engineering.

![](https://assets.underline.io/uploads/markdown_image/1/image/60f60f50c5ec37c3e781b00bc61b0c32.png)


 **Title:** From light emission to localized chemistry with gold nanoparticles: the importance of controlling plasmon relaxation
 **Speaker:** [Celine Fiorini](https://underline.io/speakers/143452-celine-fiorini-debuisschert)
 **Affiliation:** Université Paris Saclay, France
 
 **Abstract:**
 Plasmon-mediated photochemistry has now become an active area of research in nanoscience since it opens many applicative prospects from energy conversion(1) and photocatalysis,(2) to phototherapy and nanofabrication.(3-5) Plasmon based nanoscale functionalization interestingly enables e.g. the realization of advanced hybrid nanostructures for photonics.(6, 7) Despite numerous demonstrations, the exact mechanisms and main parameters driving the control of plasmon-mediated photochemical reactions remain however to be understood in detail.(8, 9) Plasmon induced chemistry is directly dependent on plasmon decay which occurs through competitive relaxation processes that need to be disentangled:(10) (1) Photonic effects through near field electromagnetic enhancement, promoting light-matter interactions in specific nanoscale locations around the NPs,(2) Electronic effects through the transfer of hot charge carriers from the excited NP to nearby chemical species,(3) Thermal effects, through the heating resulting from the lattice thermalization following electron-phonon interactions. I will try to discuss these different process in view of a recent systematic study of free radical nanophotopolymerization around gold nanospheres.(11) I will also show that the two-photon luminescence of gold nanostructures can interestingly be taken into profit for a quantitative evaluation of the magnitude of plasmonic hot spots,(12) revealing thus to be a highly valuable characterization technique.(13)
 
 Acknowledgement: The authors gratefully thank the funding agency Agence Française pour la Recherche (ANR) for their financial support of this work (project under grants HAPPLE: ANR-12-BS10-016 and SAMIRE: ANR-13-NANO-0002). 
 
 References:
 (1) Plasmons for Energy Conversion, ACS Energy Lett., virtual issue (2018) - Tang et al., J. Chem. Phys. 152, 220901 (2020).
 (2) S. Peiris et al., Catal. Sci. Technol. 6 (2016) – Cortes et al, ACS Nano (2020), 14, 16202−16219.
 (3) ML Brongersma et al., Nature Nano, 10, 25 (2015).
 (4) M. Nguyen et al., Nanoscale Horizons, 8, 8633 (2016).
 (5) F. Kameche et al., Materials Today, 40, 38 (2020).
 (6) X. Zhou et al, Appl Phys Lett., 104, 023114 (2014).
 (7) D. Ge et al, Nature Comm. (2020).
 (8) C. Gruber et al., Appl Phys Lett 106, 081101 (2015). – RG Hobbs, Nanolett 17(10) 5069 (2017). – E. Kazuma et al., Science, 360, 521 (2018). and references therein.
 (9) Y. Dubi et al., – Mascaretti et al., J. Appl. Phys. 128, 041101 (2020) – Rodio el al., ACS Catal. 10, 2345, (2020).
Gellé et al., Chem. Rev., 120, 986−1041 (2020).
 (10) F. Kameche et al., J Phys Chem C, 125(16), 8719 (2021).
 (11) C. Molinaro et al., J Phys Chem C, 120, 23136 (2016).
B. Rozic et al., ACS Nano 2017, 11, 7, 6728 - C. Molinaro et al., Phys Chem Chem Phys 20, 12295 (2018).

Session 1 - Near-Field Photonics

invited talk

The field of photonics, broadly defined, ranges from basic physical work on lasers and ultrashort laser pulses to applications in healthcare, communications, and materials. With its increasingly diverse disciplines and subdisciplines, photonics has become a key component in modern society. The scientific program consists of cross-disciplinary researchers, including chemists, physicists, and engineers, in both theory and experimentation. These researchers will discuss this rapidly expanding field and cover topics that address the latest advances in photonics related research and debate the current needs and priorities, as well as the emerging areas.

To access the AIPP Photonics in Chemical Physics conference, [please remember to register.  ](https://services.aip.org/AIPPHorizons/?confID=3351210)

AIPP Photonics in Chemical Physics

The field of photonics, broadly defined, ranges from basic physical work on lasers and ultrashort laser pulses to applications in healthcare, communications, and materials. With its increasingly diverse disciplines and subdisciplines, photonics has become a key component in modern society. 

Yohannes Abate

1

SHORT BIO

Presentations

Near-Field Photonics