The novel approach hinges on the manipulation of a transparent silicone polymer known as PDMS (Polydimethylsiloxane), processed with laser output intensity adjustments. When exposed to high-intensity laser light, the polymer’s surface transitions into a white porous structure that reflects solar radiation and emits thermal energy, thus generating cooling effects conducive to maintaining lower temperatures in hot outdoor environments. On the other hand, applying a low-intensity laser causes the formation of a black porous structure that serves the opposite function, primarily absorbing sunlight to produce heat.

This dual-functionality not only simplifies the complexity typically associated with conventional thermal management methodologies, which often require different materials and multifaceted processing to achieve the same ends, but it also suggests a new pathway towards zero-energy thermal solutions. Given the pressing realities of climate change and energy crises, the need for sustainable methods to manage temperature without additional electrical drain has never been more critical. The developed technology promises to create just such solutions—enabling environments to remain dramatically cooler during scorching summer months and warmly insulated during frigid winters.

The implications of this research extend well beyond merely regulating ambient temperatures. The team rigorously tested their novel material’s capabilities in real-world environments. Under the glaring sun, the cooling surface achieved an average temperature of 5.89 degrees Celsius lower than the surrounding environment, while the heating surface heated itself to 58.1 degrees Celsius. Such remarkable thermal regulation demonstrates not only the practicality but the outstanding performance of their novel thermal management solution.

Further simulations indicate promising potential for economic savings in energy costs should this thermal management technology be implemented in building construction. The simulations projected a staggering annual reduction of up to 26.5% in heating and cooling energy expenses when incorporating this innovative material into rooftops. This not only illustrates potential initial investment returns but also underscores the technology’s promise to contribute significantly to energy efficiency and sustainability in architectural designs.

Additionally, the incorporation of this technology may expand into ‘plus-energy’ applications. By harnessing the temperature gradient formed between the surfaces – one cooling and the other heating – researchers envision creating solar-driven thermoelectric generators capable of producing electricity from thermal differences. Such advancements could aid in meeting energy demands while simultaneously reducing reliance on traditional electrical grids.

The research’s significance is compounded by its potential applications in various sectors, from building energy efficiency to outdoor equipment thermal stability and renewable energy generation—even extending into sophisticated systems such as solar-assisted desalination processes. As a result of the simplicity and cost-effectiveness of the technology, it holds vast promise for widespread implementation across diverse fields that seek to reduce their carbon footprints.

Professor Seung Hwan Ko emphasized the groundbreaking nature of this technology in redefining thermal management strategies. The ability to seamlessly flip between heating and cooling functions using a standardized material and a singular laser process drives forward the discourse around innovative manufacturing and material science. He stated that this approach opens the door for multiple real-world applications across various industrial sectors, fundamentally altering how we perceive and manage thermal energy.

Lastly, this work underlines the urgency of adapting our technologies and communities for an environmentally sustainable future. With energy usage on the rise and the atmosphere under increasing stress from climate change, innovations such as the one spearheaded by the research team at Seoul National University could represent the kind of paradigm shift that society needs to transition towards a more energy-efficient and ecologically friendly existence.

As the world grapples with both an energy crisis and the escalating consequences of climate change, the emergence of such technologies becomes not just beneficial but essential. At a time when every degree matters in temperature regulation, the implications of this revolutionary technology could represent a quantum leap forward, one that bolsters sustainability while meeting contemporary energy demands. The path forward is illuminated with hope, as this single-material solution sets the stage for the future of energy management.

Subject of Research: Not applicable
Article Title: Monolithic Integration of Radiative Cooling and Solar Heating Functionalities by Laser-induced Pyrolysis
News Publication Date: 20-Aug-2025
Web References: 10.1016/j.joule.2025.102007
References:
Image Credits: © Joule, originally published in Joule

Keywords: Thermal management technology, cooling and heating functions, laser processing, energy efficiency, sustainability, climatic adaptation, polydimethylsiloxane (PDMS), renewable energy, zero-energy technology.

At the heart of this research lies a crystalline membrane composed of strontium titanate (SrTiO3). Previous studies by the team revealed that this material, when deposited on silicon substrates, had intriguing light-confining properties but suffered from excessive energy losses. These losses, primarily converted into heat, limited the distance that infrared light could effectively propagate, thus constraining practical uses. The new research addresses this limitation by isolating the strontium titanate membrane from direct contact with silicon, which was suspected to be the main source of the energy loss.

To probe the intrinsic characteristics of the suspended strontium titanate films, the researchers conducted detailed experiments at the Advanced Light Source facility operated by Lawrence Berkeley National Laboratory. By removing the substrate influence, they discovered that the membrane exhibited drastically reduced loss, allowing infrared light to travel four times farther than previously recorded. This low-loss attribute aligns the strontium titanate membrane’s performance with some of the most efficient polaritonic materials available today, offering promising potential for real-world applications.

The technical underpinning here involves a complex interplay between phonons, photons, and polaritons. Phonons are quantized vibrations of atoms within a material, essentially manifestations of sound or mechanical energy dissipation. Photons, on the other hand, are fundamental units of electromagnetic radiation — what we literally perceive as light. When an infrared photon couples with an optical phonon, a special quasiparticle called a phonon polariton emerges. These polaritons enable the confinement and guidance of light waves along surfaces or interfaces in ways that bulk materials cannot achieve. The strontium titanate membranes excel precisely due to their ability to sustain these surface phonon polaritons with minimal energy loss.

Another profound discovery from suspending the strontium titanate membrane was its capability to confine far-infrared light in addition to mid-infrared light. Earlier experiments restricted these films to squeezing only mid-infrared wavelengths, but the new results provide compelling experimental validation that far-infrared confinement is attainable. This expansion of operational wavelengths opens doors to novel applications, including advanced thermal management technologies where heat conversion into infrared radiation is crucial. It also enhances the sensitivity and versatility of molecular sensing devices, which rely on specific infrared wavelengths to detect chemical signatures.

The researchers emphasize the versatility of these thin films by successfully demonstrating their integration onto substrates of various geometries and materials. They suspended these membranes over void spaces and tested them on non-silicon substrates aimed at preserving the crucial low-loss properties. This adaptability distinguishes the strontium titanate films from many other polaritonic materials that often require rigid, planar, or exotic substrates, thus severely limiting their manufacturability and scalability.

Scaling production remains a pervasive challenge in nanophotonics, but this research offers optimistic prospects. The fabrication method used to create these SrTiO3 nanomembranes is more scalable compared to other techniques used for polaritonic materials. This development is vital if these membranes are to transition from the laboratory environment into commercial technologies where cost-effectiveness and reproducibility are key factors.

With these advances, the team anticipates applications ranging from next-generation infrared imaging systems to environmental sensors capable of detecting minute chemical changes. The expanded wavelength control and efficient propagation promise enhanced resolution and sensitivity, potentially transforming sectors such as healthcare diagnostics, security scanning, and chemical hazard detection.

The foundational understanding achieved also sheds light on the fundamental physics of light-matter interaction at the nanoscale. By isolating and characterizing the intrinsic properties of suspended membranes, researchers have paved the way for refined models that can predict and optimize polaritonic behavior in various materials. This deeper grasp is critical as the field moves toward complex integrated photonic circuits necessary for quantum computing and ultrafast communication networks.

Collaboration between NC State, Lawrence Berkeley National Laboratory, and the University of Geneva brought together expertise in materials science, spectroscopy, and theoretical modeling to accomplish these milestones. This multidisciplinary approach highlights the importance of combining experimental and theoretical efforts to tackle the challenges inherent in nano-optics and photonic device engineering.

The research was supported generously by agencies including the U.S. National Science Foundation, the American Chemical Society Petroleum Research Fund, and the Swiss National Science Foundation. Their commitment underscores the scientific and technological significance of developing materials that can control infrared light with greater efficiency and flexibility.

Looking forward, the team is eager to partner with industry players interested in harnessing these thin films for scalable, practical devices. The marriage of low-loss phonon polariton propagation, expansive wavelength range, and flexible integration presents an exciting frontier for innovation that could impact optical communication, thermal imaging, and beyond.

This pioneering work was detailed in the open-access paper titled “Low-Loss Far-Infrared Surface Phonon Polaritons in Suspended SrTiO3 Nanomembranes,” published in the journal Advanced Functional Materials. The paper’s lead author, Konnor Koons, alongside co-authors from NC State and international collaborators, provides comprehensive experimental data and theoretical insight validating the extraordinary potential of these suspended membranes for advancing infrared nanophotonics.

Subject of Research: Not applicable

Article Title: Low-Loss Far-Infrared Surface Phonon Polaritons in Suspended SrTiO3 Nanomembranes

News Publication Date: 12-May-2025

Web References:
https://news.ncsu.edu/2024/06/squeezing-infrared-light/
http://dx.doi.org/10.1002/adfm.202501041

References:
Koons, K., Ghanbari, R., Wang, Y., Bechtel, H., Gilbert Corder, S., Taboada-Gutiérrez, J., & Kuzmenko, A. (2025). Low-Loss Far-Infrared Surface Phonon Polaritons in Suspended SrTiO3 Nanomembranes. Advanced Functional Materials. https://doi.org/10.1002/adfm.202501041

Image Credits: Not specified

Keywords

Infrared light, thin films, strontium titanate, phonon polaritons, far-infrared confinement, mid-infrared, nanomembranes, low-loss propagation, photonics, thermal management, molecular sensing, Advanced Light Source