An international group of scientists has been diligently working to develop a unique inkable nanomaterial that holds immense potential in revolutionizing the world of ultra-thin, lightweight, and bendable displays and devices. Researchers in this study focused on the colloidal synthesis of ZnO to get a higher degree of control over the material’s properties. The results suggest some exciting applications in the manufacture of flexible displays.
The colloidal synthesis of ZnO refers to the process of producing zinc oxide nanocrystals in a colloidal suspension, where the nanocrystals are dispersed in a liquid medium. This process involves the controlled nucleation and growth of ZnO nanoparticles under specific reaction conditions, resulting in uniform and well-defined particles. Colloidal synthesis enables precise control over the size, shape, and chemical composition of ZnO nanocrystals at the nanoscale, which in turn affects their functional properties.
Traditional uses of ZnO in displays, such as in the form of thin films or bulk materials, typically do not offer the same level of control over the material’s properties. In these conventional applications, the properties of ZnO are dictated by the deposition methods, processing conditions, and the inherent properties of the material itself. These factors can lead to inconsistencies in the material’s performance, such as variations in electrical conductivity, transparency, and other optical properties.
In contrast, colloidal synthesis of ZnO nanocrystals allows for better control over these properties, making it possible to optimize the performance of ZnO in display applications. For instance, ZnO nanocrystals can be engineered to exhibit specific optical, electrical, and morphological properties that are advantageous for transparent conductive electrodes (TCEs), thin-film transistors (TFTs), and light-emitting diodes (LEDs). Furthermore, the colloidal nature of these nanocrystals enables them to be formulated into inks, which can be deposited as ultra-thin coatings on various substrates. This property makes ZnO nanocrystals particularly suitable for flexible and bendable displays and devices.
The team behind this groundbreaking research, led by Associate Professor Enrico Della Gaspera and Dr. Joel van Embden from RMIT University, had their work published in the journal, Chemical Reviews. Among the other notable researchers contributing to this project are Professor Silvia Gross from the University of Padova in Italy and Associate Professor Kevin Kittilstved from the University of Massachusetts Amherst in the United States.
The significant progress made in enables the adaptation of the properties and performances of zinc oxide by making it super small, featuring well-defined characteristics. These minuscule and versatile zinc oxide particles can be prepared with an extraordinary level of control over their size, shape, and chemical composition at the nanoscale. This unique level of precision paves the way for numerous applications across diverse fields such as optics, electronics, energy, sensing technologies, and even microbial decontamination. The possibilities for these spray-on electronics are virtually endless.
Della Gaspera has mentioned that these coatings can be made highly transparent to visible light while maintaining exceptional electrical conductivity, which are two fundamental characteristics required for the creation of touchscreen displays. Additionally, the team has discovered that these nanocrystals can be deposited at low temperatures, allowing for the creation of coatings on flexible substrates, such as plastic. The researchers are eager to collaborate with industry partners to explore potential applications using their innovative techniques for creating nanomaterial coatings.
“Scaling up our approach from the lab to an industrial setting demands the right partnerships, as scalability remains a challenge for all nanomaterials, including zinc oxide. Recreating laboratory conditions on a larger scale requires adapting the chemistry and innovative engineering in reaction setups. Additionally, we must address the shortfall in electrical conductivity that nanocrystal coatings face compared to industrial benchmarks. Despite these challenges, scientists worldwide are making significant progress. I am confident that with the right collaborations, we can overcome these obstacles,” said Della Gaspera.
Reference
van Embden, J., Gross, S., Kittilstved, K. R., & Della Gaspera, E. (2023). Colloidal Approaches to Zinc Oxide Nanocrystals. Chemical Reviews, 123(1), 271–326. https://doi.org/10.1021/acs.chemrev.2c00456
