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Do Chang Hyun

Toutes les versions de cet article : English , français

Groupe Chimie du Solide

Contact :
chang-hyun.do-AT-polytechnique.edu

▶ Ph.D student at Ecole Polytechnique
▶ Group Chimie du Solide, Plasmoxide team

Contact
▶ Address : PMC, Ecole Polytechnique, 91128 Palaiseau, France
▶ E-mail : chang-hyun.do@polytechnique.edu
▶ Phone : +33 (0)6 95 18 01 61
▶Office : Aile 5, 2nd floor, Office 05 3067B

Education/ Working Experience
▶ 2015-2021 : Bachelor degree of Information display at Kyung Hee University, South Korea
▶ 2021-2022 : IT circuit design & research, LG Display, South Korea
▶ 2022-2024 : Master degree of Energy at École Polytechnique, IP-Paris
▶ 2024-now : Ph.D student at Laboratoire de Physique de la Matière Condensée, École Polytechnique.

Research Topic

We are mainly working on the project that aims to develop near-infrared (NIR) plasmonic nanomaterials to control and amplify NIR optical processes efficiently. NIR light is particularly significant because it constitutes 49% of total solar energy, penetrates biological tissues (suitable for clinical treatments), and resonates with molecular vibrations (useful for chemical analysis). Therefore, there is a growing need for advanced NIR optics in addressing current energy and biomedical challenges.

Noble metal nanoparticles have been employed to exploit the localized surface plasmon resonance (LSPR) effect, which has practical applications in biomarkers, Raman spectroscopy, photo-thermal therapy, and solar concentration in photovoltaics. However, their use in the NIR range is limited because their LSPR is primarily centered in the visible spectrum.

Instead of noble metals, this project explores heavily doped metal oxide nanocrystals. Unlike metals, which have fixed free electron densities leading to fixed LSPR wavelengths, the free carrier density in doped metal oxides can vary significantly by adjusting doping and redox states. This variability allows the LSPR wavelength of metal oxides to be tuned across the entire infrared region while maintaining transparency in the visible range due to their large band gap. Additionally, the ability to post-synthetically and reversibly charge these oxides introduces a paradigm shift, making LSPR a modulable property.

Nanocrystalline cesium-doped tungsten oxide (CsxWO3-y) is highlighted as a promising NIR-LSPR host material because its resonance is centered in the NIR region adjacent to the visible spectrum while maintaining high transparency in the visible range. This high NIR-to-VIS selectivity is attributed to the LSPR band-splitting within the anisotropic crystal structure and morphology of CsxWO3-y

Based on fundamental studies of chemical synthesis and optical properties, our goal is to utilize CsxWO3-y nanocrystals to significantly enhance the performance of current NIR-optical materials and devices.