Tunable broadband terahertz absorption and shielding of bioderived graphitic carbon microspheres

Kulkarni, Gopal; Rane, Shreeya; Acharyya, Nityananda; Patil, Sharadchandra; Chowdhury, Dibakar Roy; Puri, Vijaya

doi:10.1016/j.ceramint.2023.09.289

Cited by 4 publications

(1 citation statement)

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“…This route demands preparing a sandwich of the hard carbon between two graphite blocks. In other investigations [ 35–37 ] molten salt, an electron beam, and a dual‐zone CVD (chemical vapor decomposition) furnace are also used to graphitize the precursors. Recently in a different strategy, our group successfully developed graphitic structures in an NGr resin (phenol‐formaldehyde) without the utilization of any metal catalysts.…”

Section: Introductionmentioning

confidence: 99%

Intervention‐Free Graphitization of Carbon Microspheres from a Non‐Graphitizing Polymer at Low Temperature: Nanopores as Dynamic Nanoreactors

Afzalalghom,

Beitollahi,

Mirkazemi

et al. 2024

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Graphitizability of organic precursors is the topic of numerous investigations due to the wide applications of graphitic materials in the industry and emerging technologies of supercapacitors, batteries, etc. Most polymers, such as polydivinyl benzene (PDVB) are classified as non‐graphitizings that do not convert to Graphite even after heating to 3000℃. Here, for the first time, the development of graphitic structure in the hierarchal porous sulfonated‐PDVB microspheres without employing specific equipment or additives like metal catalysts, organic ingredients, or graphite particles, at 1100°C is reported. The abnormal additive‐free graphitic structure formation is confirmed by Raman spectroscopy (ID/IG = 0.87), high‐resolution transmission electron microscopy (HRTEM), and selected area diffraction patterns (SAED), as well as x‐ray diffraction patterns (XRD), while preservation of aromatic compounds from the carbonization is detected by Fourier transform infrared (FTIR) analysis. Polymer evolution from room temperature to 1100°C is also studied by FTIR, Raman spectroscopy, and XRD techniques. Based on the obtained results, it is suggested that the hierarchal and complicated ink‐bottle pore network with a high surface area besides super micropores in the sulfonated‐PDVB microspheres has served as nano‐sized reaction media. These pores, hereafter referred as “dynamic nanoreactors”, are expected to have confined the in‐situ produced thermal decomposition products containing broken bond benzene rings, while changing dimensionally and structurally during the designed carbonization regime. This confinement has led to the benzene rings fusion at 250°C, a remarkable extension of them at 450°C, their growth to graphene sheets at 900°C and finally, the stacking of curved graphene layers at 1100°C. The results of this research put stress on the capability of nanopores as nanoreactors to facilitate reactions of decomposition products at low temperatures and ambient pressures to form stacked layers of graphene; A transformation that normally requires catalysts and very high pressures for only specific polyaromatic hydrocarbons.

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Section: Introductionmentioning

confidence: 99%

Intervention‐Free Graphitization of Carbon Microspheres from a Non‐Graphitizing Polymer at Low Temperature: Nanopores as Dynamic Nanoreactors

Afzalalghom,

Beitollahi,

Mirkazemi

et al. 2024

Small

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Dynamically Controllable Terahertz Electromagnetic Interference Shielding by Small Polaron Responses in Dirac Semimetal PdTe₂ Thin Films

Guo,

Chen,

Jin

et al. 2024

Adv Funct Materials

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Terahertz (THz) electromagnetic interference (EMI) shielding materials is crucial for ensuring THz electromagnetic protection and information confidentiality technology. Here, it is demonstrated that high electrical conductivity and strong absorption of THz electromagnetic radiation by type‐II Dirac semimetal PdTe2 film make it a promising material for EMI shielding. Compared to MXene film, a commonly used metallic 2D material, the PdTe2 film demonstrates a remarkable 40.36% increase in average EMI shielding efficiency per unit thickness within a broadband THz frequency range. Furthermore, it is demonstrated that a photoinduced long life‐time THz transparency in Dirac semimetal PdTe2 films is attributed to the formation of small polarons due to the strong electron‐phonon coupling. A 15 nm‐thick PdTe2 film exhibits a photoinduced change of EMI SE of 1.1 dB, a value exceeding three times that measured on MXene film with a similar pump fluence. This work provides insights into the fundamental photocarrier properties in type‐II Dirac semimetals that are essential for designing advanced THz optoelectronic devices.

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Bio-derived graphitic carbon microspheres: A green approach for high-frequency microwave absorption

Sutar,

Kulkarni,

Koli

et al. 2025

Diamond and Related Materials

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Tunable broadband terahertz absorption and shielding of bioderived graphitic carbon microspheres

Cited by 4 publications

References 42 publications

Intervention‐Free Graphitization of Carbon Microspheres from a Non‐Graphitizing Polymer at Low Temperature: Nanopores as Dynamic Nanoreactors

Intervention‐Free Graphitization of Carbon Microspheres from a Non‐Graphitizing Polymer at Low Temperature: Nanopores as Dynamic Nanoreactors

Dynamically Controllable Terahertz Electromagnetic Interference Shielding by Small Polaron Responses in Dirac Semimetal PdTe₂ Thin Films

Bio-derived graphitic carbon microspheres: A green approach for high-frequency microwave absorption

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Tunable broadband terahertz absorption and shielding of bioderived graphitic carbon microspheres

Cited by 4 publications

References 42 publications

Intervention‐Free Graphitization of Carbon Microspheres from a Non‐Graphitizing Polymer at Low Temperature: Nanopores as Dynamic Nanoreactors

Intervention‐Free Graphitization of Carbon Microspheres from a Non‐Graphitizing Polymer at Low Temperature: Nanopores as Dynamic Nanoreactors

Dynamically Controllable Terahertz Electromagnetic Interference Shielding by Small Polaron Responses in Dirac Semimetal PdTe2 Thin Films

Bio-derived graphitic carbon microspheres: A green approach for high-frequency microwave absorption

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Dynamically Controllable Terahertz Electromagnetic Interference Shielding by Small Polaron Responses in Dirac Semimetal PdTe₂ Thin Films