Researchers have found that finetuning composition of microscopic layers could yield major performance improvements in devices. The University of Ottawa team revealed that small changes to the materials and structure of the electronic devices dramatically improve their efficiency and sustainability.Because these devices rely on carefully arranged layers to conduct electricity, adjusting their composition at the microscopic level may be key in creating electronics that use less power and support more sustainable designs. By changing these layers, researchers hope to vastly improve the function of devices — particularly smaller, wearable, and biodegradable ones.Improvements can even open new uses for electronicsBenoit Lessard’s research group at the University of Ottawa is exploring different materials that can serve as the base layer for these conducting stacks, known as thin-film transistors.“It’s really important to keep in mind the bottom layer when you put the next layer on top, because it’s going to influence how that next layer organizes, how those molecules line up,” said Lessard.The team highlighted that the improvements can even open new uses for electronics, such as reducing harm from street drugs. Lessard’s group is developing sensors that can use electrochemical reactions to determine not just which substances are present in a sample, but the quantity of each.Current tests for drugs like fentanyl are “useful for telling you a yes or no,” Lessard said. But knowing exactly how much fentanyl is present in a sample would be extremely helpful both for drug users and the healthcare workers treating them.Electronic devices often depend on thin-film transistorsElectronic devices often depend on thin-film transistors, which control the movement of electrical signals and are widely used in display technologies and other electronic applications. Their performance depends not only on the materials used but also on how these materials are arranged at the molecular level.The layer beneath the active material plays a particularly important role. Its chemical composition and physical properties can influence how molecules in the upper layer align and organise themselves. Even small changes in this arrangement can affect how efficiently electrical charges move through a device and how much voltage is needed for it to function.Researchers investigated n-type Organic thin-film transistors (OTFTs) based on bis(pentafluorophenoxy) silicon phthalocyanine (F10SiPc) fabricated on a series of methacrylate-based polymer dielectrics containing Polymerized ionic liquids (PIL) units. “Using synchrotron grazing incidence wide angle X-ray scattering analysis, atomic force microscopy, and electrical characterization, we demonstrate that tuning PIL content offers control over F10SiPc orientation on the substrate,” said researchers in the study. “Increasing PIL content from 12% to 65% enables OTFT operation at voltages as low as 0.9 V, with an Ion/Ioff ratio of 104 and transconductance up to 1850 nS. This work emphasizes the importance of the dielectric/semiconductor interface for low VT OTFTs using PILs and F10SiPc.”