The new material belongs to a family of compounds known as two-dimensional hybrid organic-inorganic perovskites. These are layered semiconductors in which alternating sheets of organic and inorganic components stack into a highly ordered crystalline structure. The inorganic layers provide mechanical rigidity and structural definition, while the organic layers act as spacers whose chemical composition can be tuned almost at will. That tunability is the key to the new result. In their earlier work, the NC State team had already observed unusual combinations of stiffness and thermal behavior in this class of materials, but the new study represents a deliberate, targeted effort at molecular engineering rather than an incidental discovery.

The specific strategy involved modifying the carbon-carbon chains within the organic layers. By replacing a portion of those chains with a carefully tailored combination of benzene rings, the researchers gained precise control over how the material conducts heat and how rigid it is. Benzene rings are bulky, planar molecular units that disrupt the efficient pathways along which vibrational energy, and therefore heat, normally travels through a solid. Incorporating them in a controlled way scatters the lattice vibrations, known as phonons, that would otherwise carry thermal energy across the layers, while the overall layered architecture preserves the crystalline order that gives the film its stiffness.

The material the team produced is an azobenzene ethyl ammonium lead iodide thin film. When tested at room temperature, it exhibited a thermal conductivity of approximately 0.04 watts per meter-kelvin. To appreciate how remarkable that figure is, consider silicone, a soft polymer widely used to insulate against heat in everyday products such as oven mitts. Silicone has a thermal conductivity of about 0.2 watts per meter-kelvin, five times higher than the new perovskite film. Yet the engineered film is not a squishy insulating gel; it is a rigid semiconductor with mechanical stiffness exceeding that of silicone by a factor of roughly 700 to 10,000, depending on how the comparison is made. Combining those two figures underscores the scale of the achievement: a dense, load-bearing material that insulates better than the soft foams and elastomers engineers usually reach for when heat control matters.

Dali Sun, co-corresponding author of the study and a professor of physics at NC State, emphasizes why this combination is so valuable. Stiff materials that are good thermal insulators would have substantial utility across a wide range of applications, from cookware to electronic devices to space travel, he notes. The problem, he explains, is that in general stiff materials conduct heat well, and materials that insulate well are not stiff. The new compound is very stiff and extremely good at insulating against heat, outperforming any material one would find in nature. That framing is not marketing hyperbole but a statement about the material’s position relative to the entire known landscape of dense solids.

Jun Liu, co-corresponding author and an associate professor of mechanical and aerospace engineering at NC State, describes the work as a demonstration of what advanced molecular engineering can achieve when properties are designed intentionally rather than accepted as given. The team had previously demonstrated unusual behavior related to the combination of stiffness and thermal conductivity in a specific class of materials, she says, and for this study they engaged in more advanced molecular engineering to deliberately create an extreme combination of those properties. The result approaches the theoretical floor for thermal conductivity in a non-porous solid, meaning there is very little room left for any conventional material to do better without introducing porosity, which would sacrifice stiffness and structural integrity.

Equally important for practical adoption is the fact that the production method scales. Liu notes that the technique used to create the film can be scaled up fairly easily, allowing the material to be produced at fairly large scales, applied as a coating, and integrated into existing manufacturing workflows. This is a critical distinction from many laboratory-record thermal insulators, such as exotic aerogels or nanostructured ceramics, which achieve impressive numbers only through porous architectures that are difficult to produce uniformly over large areas and which lack the mechanical strength needed for demanding applications. A printable thin film that is both stiff and ultrainsulating opens the door to conformal thermal barriers on electronic components, protective layers in high-temperature environments, and insulation systems for aerospace structures where every gram and every millimeter counts.

The study, titled Extremely Low Thermal Conductivity in Rigid Layered Hybrid Perovskites, was published on September 18, 2026, in Science Advances. Co-lead authors are Ziqi Wang and Ankit Negi, Ph.D. graduates of NC State, along with Liang Yan of the University of North Carolina at Chapel Hill and Qingxuan Wang of Nanjing Normal University. The co-corresponding authors are Jun Liu and Dali Sun of NC State, Wei You of UNC Chapel Hill, and Jun Zhou of Nanjing Normal University. The broader author team includes contributors from NC State, UNC Chapel Hill, Texas A&M University, Yale University, Shanghai Polytechnic University, and Wenzhou University, reflecting the collaborative experimental and computational effort required to synthesize, characterize, and model the material’s behavior.

The research was supported by the National Science Foundation under multiple grants, by the U.S. Department of Energy, by the Office of Naval Research, and by the Goodnight Innovation Distinguished Professor Endowment. Beyond the specific compound, the authors point to the broader significance of the work: it highlights the potential of molecular engineering to fine-tune hybrid layered materials for applications that require novel combinations of stiffness and thermal insulation. If the same benzene-ring design principle can be extended across other members of the hybrid perovskite family and into related layered systems, the coming years could see a new generation of structural materials in which heat management is designed into the molecular architecture itself rather than bolted on afterwards. For engineers designing everything from smartphone processors to spacecraft heat shields, that prospect transforms thermal insulation from a compromise into a design variable.

Subject of Research: Development of a rigid two-dimensional hybrid organic-inorganic perovskite thin film with extremely low thermal conductivity achieved through molecular engineering of organic layers.

Article Title: New thermal insulator outperforms any material found in nature

Article References: New thermal insulator outperforms any material found in nature. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: thermal insulation, hybrid perovskites, molecular engineering, thin films, thermal conductivity, materials science, NC State University, Science Advances, stiffness, phonon scattering, benzene rings, thermal barriers