Sustainable materials enabled terahertz functional devices

Terahertz (THz) technology holds immense potential across fields as diverse as high-speed wireless communication, biomedical diagnostics, security imaging, and quantum sensing. However, realizing its full potential hinges on materials that are not only functionally efficient but also sustainable and environmentally conscious. Now, researchers from the College of Textile and Clothing Engineering at Soochow University, led by Professor Hualing He, present a comprehensive review titled “Sustainable Materials Enabled Terahertz Functional Devices.” This work offers a timely roadmap for harnessing green and low-carbon materials to drive the future of THz science and engineering.

Why Terahertz—and Why Sustainability?

Positioned between microwaves and infrared radiation, the terahertz frequency band (0.1–10 THz) enables unprecedented capabilities such as non-invasive imaging, ultrafast data transmission, and sensitive spectroscopy. Yet, conventional materials used in THz components—such as toxic semiconductors, expensive metals, and rare inorganic crystals—pose environmental and economic concerns. The drive toward low-carbon, biodegradable, and earth-abundant materials is therefore not only timely, but essential.

Green Materials at the Forefront of THz Innovation

This review highlights a wide range of sustainable materials that are actively shaping the THz landscape:

• Carbon-based materials such as graphene, carbon nanotubes (CNTs), and biomass-derived carbon offer excellent conductivity, tunability, and optical properties in the THz domain. Their lightweight, flexible nature supports wearable or conformal THz devices.
• Natural polymers including cellulose, chitosan, and silk serve as biodegradable substrates and dielectric layers. These materials exhibit low THz absorption and good mechanical properties, making them ideal for eco-friendly electronics.
• Metal-organic frameworks (MOFs) and perovskites are explored for their unique porous structures and photoresponsive behavior, enabling tunable THz sources and modulators with low environmental impact.
• Recyclable and biocompatible oxides like ZnO, TiO₂, and BiFeO₃ have been employed in THz emission and detection, offering promising paths toward sustainable optoelectronic platforms.

THz Functional Devices: From Emitters to Detectors

The article categorizes sustainable THz-enabled devices into four main types:

1. THz Emitters
   Utilizing optical rectification, photoconductive antennas, or nonlinear processes, sustainable materials like graphene and hybrid composites have been engineered to produce THz radiation under low-power excitation.
2. THz Detectors
   Devices based on pyroelectric, bolometric, or field-effect mechanisms leverage materials such as silk, CNTs, or cellulose derivatives to achieve sensitive, broadband THz detection with high thermal stability.
3. THz Modulators and Filters
   Smart materials—including bio-derived films and phase-change materials—enable real-time tunability of THz waves for filtering, switching, and dynamic imaging.
4. THz Waveguides and Metasurfaces
   Flexible, low-loss substrates based on paper, fabric, or biodegradable polymers are used to fabricate metastructures that manipulate THz propagation with minimal ecological footprint.

Challenges and the Path Forward

Despite exciting progress, the review underscores several key hurdles:

• Material uniformity and long-term stability remain bottlenecks for scalable production.
• Integration with microfabrication processes and existing silicon-based systems is still limited.
• Quantitative sustainability assessment, such as life cycle analysis (LCA), is rarely reported but critical for truly green development.

To address these gaps, the authors advocate for cross-disciplinary collaboration among chemists, materials scientists, device engineers, and environmental analysts. Future directions include hybrid organic-inorganic systems, additive manufacturing techniques, and AI-guided material discovery tailored for THz applications.

Toward a Sustainable Terahertz Future

This review makes a compelling case that sustainability and performance are no longer mutually exclusive. As global demand for THz-enabled technologies surges, particularly in wireless communication (6G and beyond), healthcare monitoring, and environmental sensing, the integration of eco-friendly materials will become not just desirable, but imperative.

By mapping the current progress and outlining future needs, this article lays the groundwork for a new generation of terahertz devices that are efficient, scalable, and environmentally responsible—bringing us one step closer to a greener, smarter technological future.