Selective Optical Properties for Improving Radiative Cooling Potential in 2D Cementitious Materials: On the Search for Photonic Metaconcretes
ORAL
Abstract
Although cement is widely perceived as a structural material, its nanostructure exhibits quasi-2D physics arising from lamellar calcium silicate hydrate (C–S–H) frameworks [1,2]. These layered Ca–O sheets, crosslinked by silicate chains, resemble defective tobermorite and challenge the notion that technologically relevant 2D materials are limited to van der Waals crystals. Their intrinsic anisotropy, together with hierarchical disorder in real cements, gives rise to emergent photonic properties.
We present first-principles calculations (DFT, many-body GW, and Bethe–Salpeter equation) of the optical and excitonic properties of cement constituents: CaO, SiO₂, belite, alite, portlandite, tobermorite-like C–S–H, and relevant nanoadditions such as gypsum and calcite [3,4]. We find that anisotropic excitons and strong polar optical modes govern their mid-infrared dielectric response. In particular, selective emissivity in the 8–13 μm atmospheric transparency window arises from Si–O and S–O vibrational resonances, enabling passive radiative cooling. Together with high visible/near-IR reflectivity, these features define a new class of photonic meta-concretes that link condensed matter physics, nanophotonics, and sustainable energy materials [5].
[1] A. Ayuela et al. J. Chem. Phys. 127, 164710 (2007).
[2] A. J. Allen, J. J. Thomas & H. M. Jennings. Nature Materials 6, 311–316 (2007).
[3] J. Janovec, J. S. Dolado & A. Ayuela. J. Mater. Chem. C 13, 6267-6276 (2025).
[4] J. Janovec, R. Agbaoye, J. S. Dolado & A. Ayuela. Energy & Environmental Materials (accepted).
[5] J. S. Dolado et al, ACS Applied Optical Materials 2, 1000-1009 (2024).
We present first-principles calculations (DFT, many-body GW, and Bethe–Salpeter equation) of the optical and excitonic properties of cement constituents: CaO, SiO₂, belite, alite, portlandite, tobermorite-like C–S–H, and relevant nanoadditions such as gypsum and calcite [3,4]. We find that anisotropic excitons and strong polar optical modes govern their mid-infrared dielectric response. In particular, selective emissivity in the 8–13 μm atmospheric transparency window arises from Si–O and S–O vibrational resonances, enabling passive radiative cooling. Together with high visible/near-IR reflectivity, these features define a new class of photonic meta-concretes that link condensed matter physics, nanophotonics, and sustainable energy materials [5].
[1] A. Ayuela et al. J. Chem. Phys. 127, 164710 (2007).
[2] A. J. Allen, J. J. Thomas & H. M. Jennings. Nature Materials 6, 311–316 (2007).
[3] J. Janovec, J. S. Dolado & A. Ayuela. J. Mater. Chem. C 13, 6267-6276 (2025).
[4] J. Janovec, R. Agbaoye, J. S. Dolado & A. Ayuela. Energy & Environmental Materials (accepted).
[5] J. S. Dolado et al, ACS Applied Optical Materials 2, 1000-1009 (2024).
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Publication: - A. Ayuela et al. J. Chem. Phys. 127, 164710 (2007).
- J. Janovec, J. S. Dolado & A. Ayuela. J. Mater. Chem. C 13, 6267-6276 (2025).
- J. Janovec, R. Agbaoye, J. S. Dolado & A. Ayuela. Energy & Environmental Materials (accepted).
- J. S. Dolado et al, ACS Applied Optical Materials 2, 1000-1009 (2024).
Presenters
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Andres Ayuela
- Centro de Física de Materiales-MPC (CSIC-UPV/EHU), DIPC