An international group of researchers from Sant’Anna School and Graz University of Technology, under the direction of Associate Professor Francesco Greco, has successfully converted the ink from a red marker pen into a graphene-based electrical circuit. This study demonstrates the potential use of everyday materials in advanced electronic applications.
Passing a laser beam over the ink transforms it into a form of porous and conductive carbon called ‘laser-induced graphene’ (LIG). So far, we believed that it was possible to obtain this LIG only from particular plastic materials and polymers, and this somehow limited its applications. An ink or paint, on the other hand, can be used easily and anywhere to coat other objects. They also represent an economically advantageous alternative.
Francesco Greco, Associate Professor, Bioengineering, Sant’Anna School of Advanced Studies
From Ink to… Graphene. The Role of the Dye Called Eosin
A common office supply—a red marker like those used on whiteboards—was the unexpected inspiration for a recent study under the European project 5DNanoprinting. The key ingredient was eosin, a dye found in certain red inks, known for its high thermal stability and structural similarity to graphene.
Alexander Dallinger, a postdoctoral researcher at the University of Graz’s Institute of Solid State Physics, was the first to notice eosin’s unusual behavior. He observed that when exposed to laser radiation, the dye responded in unexpected ways, prompting further investigation.
The initial discovery happened by chance. I was trying laser writing on other materials, without success: none of them were transformed into conductive graphene. I had written on one of the samples its name with a red marker to recognize it. By mistake (or luck?), the laser beam passed over the writing: right at that point, I saw a black trace appear.
Alexander Dallinger, Post-Doc, Institute of Solid State Physics, University of Graz
Dallinger said, “Intrigued, I immediately analyzed it: the trace was conductive and it was graphene! This led to many questions: What is the marker ink made of? Why does that marker work and others do not? What is the ‘secret ingredient’? These questions were the starting point for the whole study and the discoveries that led to this publication.”
The “Paint & Scribe” Approach: An Electric Circuit Can Be Created On Any Surface
To begin transforming the dye into a functioning circuit, the research team applied the red ink onto a surface of their choice, ranging from paper to coffee cups or even eyeglasses. They then designed the desired electronic circuit using computer software.
Next, a laser system traced the digital design directly onto the dyed surface. Upon laser exposure, the eosin dye underwent a chemical transformation, converting into a conductive form of graphene.
“This approach, called ‘Paint & Scribe’, integrates a graphene-based electrical circuit on any surface, induced by a laser: paint an object, then pass the laser over it and you get a circuit. It is an innovative system considering that, until now, graphene-based electrical circuits were only obtained on polymeric precursors,” explains Greco.
Pisa-Firenze-Graz: The Innovation Triangle
Key contributions also came from Rodorico Giorgi and Rachel Camerini—an Associate Professor and a Postdoctoral Fellow, respectively—at the University of Florence’s “Ugo Schiff” Department of Chemistry and the Center for Colloid and Surface Science (CSGI).
Their expertise in color and pigment chemistry was essential for analyzing the ink composition and identifying which dyes were responsible for the graphene formation.
We work in the field of Cultural Heritage, studying the matter and this transformation. It is surprising how knowledge of the properties of organic dyes suddenly turns out to be the key to interpreting a phenomenon never seen before. You know a lot of things, but you cannot explain everything. Then one day, you put two pieces of a puzzle together and take a step forward. That is the beauty of science!
Rodorico Giorgi, Associate Professor, University of Florence
Possible Applications
Greco said, “I believe that our study is an example of how scientific curiosity can unexpectedly lead to practical and applicative implications. In fact, this study, besides analyzing why only some dyes are suitable for transformation into LIG, aims to propose this method for the realization of circuits and sensors on any surface. Instead of installing circuits or sensors (often heavy, expensive, and bulky) on the objects to be sensorized, we can now think of ‘writing’ them directly where they are needed.”
“This could give a boost to applications in many sectors: printable electronics, biomedical sensors, robotics, automation, and environmental sensors. We are already working on some of these applications. We have also started to study other dyes derived from natural materials, with to the aim of creating green electronics,” Francesco Greco concluded.
Journal Reference:
Dallinger, A., et al. (2025) Laser‐Induced Graphene from Commercial Inks and Dyes. Advanced Science. doi.org/10.1002/advs.202412167.
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