Modern life runs on electronics. From smartphones to sensors, their presence is ubiquitous — and so is their environmental footprint. Each year, more than 60 million tonnes of electronic waste are generated worldwide. Much of it consists of non‑recyclable substrates and metals that persist in the environment for decades.

Recycling, where it exists, often requires temperatures exceeding 1000 °C and the use of hazardous chemicals. Against this backdrop, the question is no longer whether electronics must become more sustainable but how, fundamentally, we are willing to rethink them. Designing greener devices, therefore, is not merely an innovation challenge; it is a responsibility.

One of the key goals in sustainable electronics is the development of biodegradable substrates—such as bio‑based polymers or natural fibre materials—that could help shift the industry toward a more circular model, reducing pollution and conserving resources. For Prof. Hans Kleemann and his team at TU Dresden, this rethink did not begin in a cleanroom, where circuits are typically patterned, but under a magnolia tree.

That moment of curiosity gave rise to Leaftronics, a concept that proposes something deceptively simple: using natural leaf structures as functional scaffolds for electronic systems. “I’m not entirely sure Leaftronics is a widely known term yet,” Kleemann says with a smile, “but we’re certainly working on it with great enthusiasm. Even if the name isn’t universal, the underlying idea resonates strongly with many people — both researchers and non‑researchers.”

Scientific insight rooted in nature

The origin of Leaftronics reads almost like scientific folklore. The concept emerged from the work of Kleemann’s former PhD student, Rakesh Nair, who was searching for decomposable alternatives to conventional substrates such as glass or plastic. Solution‑processed polymers and paper substrates were tested, but none survived moderate heating. “Everything failed when heated to even moderate temperatures,” Kleemann recalls. Then came the unexpected insight. “While struggling with the problem one day, he happened to walk past the magnolia tree next to our institute and realised that leaves might hold a solution,” he explained. The question was elegant in its simplicity: “What if we could use what trees use to build leaves — and improve upon it?”

Back in the lab, the team chemically etched away the green mesophyll layers, exposing the delicate lignocellulosic vein network beneath. What remained was a quasi-fractal scaffold: lightweight, mechanically robust, and naturally optimised for transport and structural reinforcement. “When he brought the result to my office and showed me the delicate structures he’d uncovered, I was instantly fascinated,” Kleemann says.

In nature, the vein network allows leaves to grow into thin yet stable films while simultaneously transporting water and nutrients. In electronics, that same architecture can act as a sequestering matrix — stabilising polymers that would otherwise melt and flow at elevated temperatures. Lignocellulose itself turns out to be “a surprisingly thermomechanically stable material”.

And so what began as a speculative experiment quickly expanded into a research platform. Gas separation membranes, battery separators, water filtration systems—and, crucially, substrates for printed circuit boards (PCBs)—emerged as potential applications. As Kleemann puts it with characteristic wordplay, “It’s unbeLEAFable.”

The PCB application was the first to be practically realised.

The elephant in the room: printed circuit boards

To understand the disruptive potential of Leaftronics, one must consider the role of printed circuit boards. PCBs are the structural and electrical backbone of virtually all electronic devices. They are engineered for mechanical, chemical, and thermal robustness—qualities that underpin modern performance but also introduce a paradox. “Electronic devices are inherently complex because we continuously demand higher performance,” Kleemann explains. “From a thermodynamic perspective, complexity always comes at a cost.”

In practice, that cost manifests throughout a product’s life cycle. When devices fail or become obsolete, it is often not the PCB that has reached its physical limit; instead, obsolescence is driven by software updates, consumer behaviour, or the failure of a single component.

“At each stage of a product’s life cycle, we need to ask a fundamental question: what actually limits the lifespan of this product?” Kleemann says. In many cases, the PCB is what he calls “the elephant in the room”: durable enough to last far longer than the device itself, yet extremely difficult to recycle without extreme temperatures and fluorinated chemicals. Leaftronics does not aim to incrementally tweak this system; its goal is to redesign it entirely.

“Our ambition is not to optimise recycling for today’s PCBs,” Kleemann emphasises, “but to design entirely new ones based on biomaterials, where performance and sustainability are integrated from the very beginning — not treated as competing goals.”

Beyond efficiency: Reduce, Reuse, Recycle

Sustainability discussions in electronics often focus on efficiency gains or improved recycling techniques. For Kleemann, that framework is insufficient. Leaftronics embodies this prioritisation. “Efficiency and recycling are important, but they alone won’t get us far enough to bring our planet back into balance,” he states. Instead, he invokes a familiar hierarchy: “Reduce, Reuse, Recycle — exactly that order”. The aim is to create electronic systems that can be recycled if necessary, reused wherever possible, and reduced in material demand when feasible.

By designing printed circuit boards that facilitate modularity and repair, the group hopes to extend component lifetimes and reduce the need for new electronics. Yet technology alone cannot accomplish this shift. “We have to recognise that technology alone won’t be enough: we also need a shift in societal behaviour and attitudes toward consumption, repair, and longevity,” he cautions. In this sense, Leaftronics is as much a socio-technical vision as it is a materials innovation.

Joachim Herz Prize: Interdisciplinarity boosts Leaftronics impact

Developing leaf-based printed circuit boards demands expertise across disciplines: physics to understand electrical and thermal behaviour, materials science to tailor substrates, biotechnology to process and potentially decompose biomaterials, and engineering to meet industrial standards.

“I strongly believe in the power of interdisciplinary research,” Kleemann says. But interdisciplinarity, in his view, is not a loose collaboration. It requires shared purpose. “The key is bringing together true experts from different fields and finding a question or challenge that excites all of them,” he explains. When that happens, something transformative occurs: “The individual expertise doesn’t just add up, it multiplies, each researcher’s contribution gains impact by being part of a broader, more integrated solution”.

This philosophy underpins the broader ambitions of Leaftronics and is reflected in its recent recognition with the Joachim Herz Prize, which Kleemann describes as “the most significant milestone of my career so far.”

Beyond prestige, the prize supports a research project that recognises not only scientific excellence, but also a commitment to addressing socially, economically, and ecologically relevant questions, and to translating ideas into real-world impact through entrepreneurial thinking. The funding enables Kleaamman’s scientific team to conduct fundamental investigations at the intersection of biotechnology, process engineering, and electronics, aiming to identify biological methods to both construct and decompose leaf-based printed circuit boards. This could open up entirely new ways to reduce the environmental impact of electronic waste.

However, the path from laboratory proof-of-concept to commercial adoption is long and complex. “A radically new bio‑based substrate must meet established PCB industry standards (flammability, thermal expansion, moisture uptake, solvent resistance) ”, Kleemann claims with pragmatism. “Some challenges have already been addressed; others will only become visible at industrial scale. Upscaling requires resources, industrial partnerships, and patience.”

Society’s role in technological transformation

Ultimately, however, it is also necessary to have a deeper ethical reflection on even the most elegant materials innovation cannot scale without societal alignment .“No technology will make it from the lab to large-scale production unless there is a market for it,” Kleemann states and underlines how “markets, in turn, are shaped by policy and public demand”. He does not shy away from blunt metaphors: “We are like a society of drug addicts, asking the supplier to stop selling it while still buying more” he says, and keeps reminding us how: “for sustainable technologies to flourish, clear and enforceable regulations are required, democratic societies” he argues “possess the power to demand this alignment. “The “silent majority” that supports sustainability must become more vocal”.

Despite these challenges, he remains optimistic. The response to Leaftronics from researchers, industry representatives, and the public has been overwhelmingly enthusiastic. “When people ask us when they’ll be able to buy devices based on this technology, that excitement is incredibly motivating,” he says.

Learning from leaves

“Leaves are ephemeral. They grow, perform complex biochemical tasks, adapt to environmental stress, and eventually decompose, returning nutrients to the soil. They do not persist as toxic waste for centuries. Leaftronics does not romanticise nature. It does not propose abandoning performance or technological ambition. Instead, it asks whether high-performance electronics can be designed with lifecycle awareness embedded from the outset. In doing so, it reframes sustainability not as an afterthought — a recycling challenge at the end of life — but as a design principle at the beginning. Electronics may never fully behave like leaves. But if future circuit boards carry within them even a fraction of nature’s structural elegance and lifecycle intelligence, the industry’s environmental footprint could change profoundly. And it all started with a moment of curiosity beneath a magnolia tree”, concludes Kleemann.

Featured Image: Hans Kleemann. Adapted with permission, original photograph taken by Rakesh Nair.