Microstructure-driven terahertz absorption in single-layer graphene: Statistical insights from random grain-boundary networks

Ji, Zhonghang, Zhao, Junxuan, Wang, Zuobin and Zhu, Hanxing ORCID: https://orcid.org/0000-0002-3209-6831 2026. Microstructure-driven terahertz absorption in single-layer graphene: Statistical insights from random grain-boundary networks. Materials & Design 268 , 116471. 10.1016/j.matdes.2026.116471

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Abstract

Polycrystalline graphene exhibits stochastic grain morphologies that strongly affect its terahertz (THz) electromagnetic absorption, yet most existing models rely on idealized or periodic assumptions that overlook the statistical nature of grain–boundary networks. Here, we develop a statistically grounded framework that quantitatively links microscopic randomness to macroscopic THz absorption. Voronoi–generated morphologies with independently tunable grain size, grain–boundary resistance, and structural regularity are combined with a frequency–dispersive surface–conductivity model. An L9(33) orthogonal design with K = 10 realizations per configuration enables systematic evaluation of multivariate effects and their variability. Absorption arises from the interplay between scattering-induced field confinement and boundary-mediated dissipation, both governed by grain–network topology. Large grains and moderate–to–high boundary resistance promote continuous dissipative pathways, whereas excessive structural perturbation disrupts connectivity and weakens absorption. Field maps confirm that strong absorption corresponds to extended high-intensity channels along grain boundaries. Scale–up validation using 3 × 3 supercells agree closely with unit–cell ensemble averages, demonstrating that the identified mechanisms persist across larger domains. This study establishes statistically validated structure–property relationships for THz absorption in polycrystalline graphene and identifies the microstructural conditions required for forming continuous dissipative pathways, providing a practical basis for microstructure–engineered absorber design and for understanding dissipation in disordered two–dimensional materials.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Engineering
Publisher:	Elsevier BV
ISSN:	0264-1275
Date of First Compliant Deposit:	6 July 2026
Date of Acceptance:	19 June 2026
Last Modified:	07 Jul 2026 08:48
URI:	https://orca.cardiff.ac.uk/id/eprint/187951

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