Synergistic polarization effect of selenium-deficient quantum dots integrated carbon nanotubes for superior electromagnetic wave absorption

Abstract

Vacancy engineering stands as a crucial strategy for modulating the electrical properties and crystal structures, presenting a promising avenue for advancing electromagnetic (EM) absorption materials. However, designing high-efficiency absorbers with a high density of vacancies remains a significant challenge, with the vacancy-induced loss mechanisms still not fully elucidated. Herein, the vacancy-induced loss mechanism in virtue of carbon nanotubes threaded through quantum dots, which are embedded in carbon nanospheres and feature selenium-rich vacancies (V-C/NiCoSe), is meticulously designed using the MOF template method. Temperature-regulated defect analysis in V-C/NiCoSe composites unveils the existence of selenium vacancies, with experimental results indicating that their concentration increases with rising annealing temperature. By strategically engineering selenium vacancies, we achieve optimal dielectric loss, resulting in an effective bandwidth of 3.46 GHz and a minimal reflection loss (RL_min) of −46.8 dB at a thickness of 2.0 mm. This research provides a simple yet highly effective approach for enhancing EM absorption performance and corrosion resistance in harsh environments, utilizing a template-based method to introduce abundant vacancies.