Science & Technology, UK (Commonwealth Union) – A breakthrough discovery by researchers has paved the way for the manipulation of light and quantum ‘spin’ interactions within organic semiconductors, even at room temperature.
In the realm of quantum physics, ‘spin’ denotes the intrinsic angular momentum of electrons, which manifests as either an ‘up’ or ‘down’ orientation. The utilization of electron spin states—up and down—instead of the traditional 0 and 1 in conventional computer logic presents the potential to revolutionize information processing in computers. Additionally, quantum-based sensors could offer substantial enhancements in our capacity to measure and explore the surrounding world.
Led by the University of Cambridge, an international consortium of researchers has achieved a groundbreaking feat: utilizing particles of light as a form of ‘switch’ to establish connections and govern the spin of electrons. This innovation transforms these electrons into minuscule magnets, holding immense promise for quantum applications.
The ingenious approach involved the creation of modular molecular units linked through minute ‘bridges.’ By shining a light on these bridges, electrons located at opposing ends of the structure were able to connect by aligning their respective spin states. Remarkably, even after the bridge was removed, the connected electrons sustained their alignment through spins.
Typically, exerting this level of control over quantum properties demands extremely low temperatures. Nonetheless, the team under the guidance of Cambridge has achieved mastery over the quantum behaviors of these materials at room temperature. This achievement heralds a new era of potential quantum applications, as the coupling of spins with photons becomes a reliable possibility. The findings have been documented in the journal Nature.
Virtually every facet of quantum technology, which stems from the peculiar characteristics of subatomic particles, hinges on spin. As electrons navigate their pathways, they typically create stable pairs—one with spin up and the other with spin down. However, it is feasible to produce molecules that house unpaired electrons, often referred to as radicals. While most radicals exhibit high reactivity, meticulous molecular design can yield chemically stable variations, offering new vistas in the realm of scientific exploration.
“These unpaired spins change the rules for what happens when a photon is absorbed and electrons are moved up to a higher energy level,” explained 1st author Sebastian Gorgon, from the University of Cambridge, Cavendish Laboratory. “We’ve been working with systems where there is one net spin, which makes them good for light emission and making LEDs.”
Gorgon works within the research group led by Professor Sir Richard Friend, where a focused exploration of radicals within organic semiconductors has been underway, particularly in the context of light generation. A few years back, the team uncovered a collection of stable and brilliantly luminous materials. This breakthrough has positioned these materials to outperform even the most superior conventional organic light-emitting diodes (OLEDs) in the realm of red light emission.
Dr. Emrys Evans, who co-led the research from Swansea University, indicated the significance of amalgamating methodologies from diverse scientific domains. He further indicated that, leveraging techniques derived from various disciplines was pivotal. The research team brings substantial proficiency from the realms of physics and chemistry, encompassing areas such as electron spin properties and the optimization of organic semiconductors for LED applications. This collective expertise played a pivotal role in our ability to prepare and scrutinize these molecules in their solid-state form, a prerequisite for showcasing quantum effects at room temperature.
Organic semiconductors have established themselves as the forefront of lighting and commercial display technologies. These materials have the potential to offer a more sustainable alternative to silicon in the domain of solar cells. Despite their prominence in these fields, they have not received extensive attention in the context of quantum applications, which span quantum computing and quantum sensing. Gorgon articulated the progress achieved, indicating, that they’ve taken a significant leap forward by establishing a connection between the optical and magnetic attributes of radicals within an organic semiconductor. This development augurs well for entirely novel applications, as it obviates the requirement for ultra-cold temperatures.
