Researchers at the University of Michigan have achieved a groundbreaking discovery in the realm of materials science by developing a novel variant of silicone that exhibits semiconducting properties. This innovative material challenges the long-standing perceptions that silicones, traditionally known for their insulating characteristics, are incapable of conducting electricity or heat effectively. The study’s lead author, Zijing (Jackie) Zhang, a doctoral student at U-M, illustrates that this development could herald a new era in the production of soft, flexible electronics across various applications.
Historically, silicones have been predominantly viewed as electrical insulators. Due to their chemical structure, which consists of alternating silicon and oxygen atoms (Si—O—Si) along with carbon-based groups, they are often employed in numerous industrial applications, including biomedical devices, sealants, and electronic coatings. These insulating materials have effectively blocked electricity and heat, prompting the assumption that they could never serve as viable conductors in any capacity. However, the research team has uncovered a transformation that enables silicone to switch roles and function as a semiconductor.
The implications of this discovery are vast and exciting. Richard Laine, a professor of materials science and engineering and a co-author of the study, emphasizes that the newfound semiconducting capabilities of this silicone variant could pave the way for innovative flat-panel displays, flexible solar panels, and even wearable technology that can display dynamic images or patterns. This versatility moves beyond traditional rigid materials that have typically dominated the semiconductor landscape. This opens the door to an ecosystem of advanced electronics that are not only portable but also adaptable and colorful.
At the molecular level, the team explored the ramifications of various structures in silicone, particularly focusing on cross-linking mechanisms, which can significantly alter the physical properties of polymers. Their investigation led to the identification of a specific copolymer that merges linear and cage-structured silicones. This combination revealed unexpected electrical conductivity and represents a marked departure from the paradigmatic understanding of silicones as inert materials.
Central to this electrical conductivity is the movement of electrons across the Si—O—Si bonds. When electrons transition from a ground state to an excited state—essentially “jumping” up to a higher energy level—they are able to traverse the structural matrix within the silicone material. In conventional silicon materials, Si—O—Si bond angles do not facilitate such conductivity. However, the researchers found that in the copolymer discovered, the bond angles increased from 140° in the ground state to 150° in the excited state, enabling electrical charge to flow more freely.
Laine clarifies that the length of the copolymer chain plays a pivotal role in the material’s electrical properties. The longer the chain, the more favorable the conditions for electron mobility become, thus permitting electrons to travel greater distances with reduced energy expenditure. This phenomenon is particularly critical when considering the material’s potential use in energy-efficient devices, as it lowers the energy needed for light absorption and subsequent emission, allowing the material to be harnessed in exciting new applications.
Alongside its electrical properties, the research has revealed that this semiconducting silicone variant can also exhibit diverse colors. The color outcomes depend on the chain length within the copolymer. As electrons absorb and emit photons during transitions, the nature of these transitions correlates directly with the length of the copolymer chain. Longer chains result in lower energy emissions, shifting the color toward the red spectrum, while shorter chains yield higher energy outputs, positioning the emitted light closer to blue hues. This unique ability to display colors is not only aesthetically pleasing but also functional, potentially leading to innovations in display technologies and integrated electronics.
To visually illustrate their findings, the research team conducted an experiment in which they separated copolymers of varying chain lengths into test tubes. When exposed to ultraviolet (UV) light, a captivating spectrum emerged as varying lengths absorbed and emitted light differently, resulting in a vivid rainbow effect. This demonstration underscores the material’s potential for creative applications in fields as diverse as fashion, wearable technology, and even visual art.
Historically, silicones have garnered a reputation for their transparency and whiteness due to their insulating nature, limiting their functional utility and aesthetic charm. This research redefines the material, transforming it from a perceived obstacle into a cornerstone of future technological advancements. It presents an opportunity to create soft, bendable electronics and displays that challenge the conventions of traditional electronic components.
In summary, the University of Michigan’s development of semiconducting silicone embodies an exciting shift in material science, revealing an unexpected avenue for rich, colorful, and flexible electronics. As further exploration and refinement of this technology unfolds, it promises substantial implications for numerous industries that rely heavily on electronic interfaces and displays. The ability to manipulate not just the electrical properties but also the visual characteristics of silicone could spark an evolution in design, functionality, and utility across countless applications.
This remarkable finding is supported by funding from the U.S. National Science Foundation and the Thailand National Science, Research and Innovation Fund. As the research continues to move forward, it is likely that new dimensions of application for semiconducting silicones will emerge, cementing their place in the future of electronics and materials modeling.
Subject of Research: Novel semiconducting silicone variants
Article Title: New Silicone Variant Discovered as a Semiconductor
News Publication Date: October 2023
Web References: https://mse.engin.umich.edu
References: DOI: 10.1002/marc.20250008
Image Credits: University of Michigan
Tags: advancements in soft electronicsconductive silicone materialselectrical conductivity in siliconesflexible electronics innovationsinsulation to conduction transformationmaterials science breakthroughsnovel silicone applicationssemiconducting properties of siliconesilicone chemical structuresilicone in biomedical devicesUniversity of Michigan researchZijing Jackie Zhang research
