3D printing has long since escaped the pages of science fiction books. It’s woven into our everyday lives. This year, the global 3D printing market is expected to exceed €30 billion, with projections indicating it will double within the next five years. Yet we’re only beginning to scratch the surface of how this technology can truly change our world.

3D printing is steadily advancing to the micro- and nanoscale, where, as research by Vilnius University (VU) scientist Artūras Harnik suggests, it may play a key role in developing the next generation of lasers.

The Smaller, the Better

3D printers are already producing a wide range of objects, and some researchers envision a future in which we could even print functional human organs. But as Harnik, a doctoral student at VU’s Faculty of Physics, points out, that future is still a long way off. Printing at the micro- and nanoscale demands extraordinary precision. This challenge becomes even more complex when luminescent (light-emitting) materials are involved.

To advance the field, Harnik and colleagues from Lithuania and Greece conducted a comprehensive review of existing 3D printing methods and their potential applications. That work culminated in a paper published in the prestigious journal Advanced Optical Materials.

“It’s a real achievement,” Harnik says. “We’d submitted to journals like this before, so we knew how rigorous the selection process is. If the paper isn’t thorough enough, it won’t make the cut. And then there’s the review process itself – feedback, revisions, back and forth – sometimes several rounds before anything gets accepted.”

Their analysis clarifies why micro-scale 3D printing is attracting considerable attention. The technology enables applications such as photonic crystals and waveguides, but what researchers find particularly exciting is the ability to spatially structure luminescent materials, with potential applications in bioimaging, microlasers, and micro-LEDs.

Prof. Mangirdas Malinauskas and Artūras Harnik. Photo by Vilnius University

“There could be an immense range of their applications,” Harnik explains. “Our main focus is on components for microlasers, optics, and micro-optics. Being able to print tiny components is a big deal – they could find their way into medical devices, robotics, and beyond.”

Three Approaches to Printing

The review identifies three categories of luminescent materials suitable for 3D printing: organic, hybrid, and inorganic, each with distinct trade-offs.

Organic materials are the easiest to work with, as they require no mixing with inorganic particles. Hybrids introduce a small proportion of inorganic content, which complicates the process. Meanwhile, inorganic structures are the most demanding of all: after printing, the object must undergo calcination – a high-temperature process that breaks down carbonates and hydrates in the base material.

Each material type has its inherent strengths. Organic ones, for instance, tend to have low evaporation temperatures, which means they can’t withstand high heat and are prone to fading over time. Hybrids share some of those characteristics but are more heat-resistant and mechanically tougher. Inorganic compounds, such as ceramics and crystalline materials, are in a league of their own when it comes to stability, remaining solid up to around 1,000°C.

This paper is part of Harnik’s doctoral research, and he plans to continue exploring 3D printing with luminescent materials well into the future. For him, that work isn’t just academically interesting. It’s the necessary groundwork for the technology to fulfil its real-world promise.

“What’s exciting is that this is the first review article to examine the 3D printing of luminescent micro and nanostructures in this kind of depth,” he says. “Not just luminescent structures in general, but this specific intersection. Hopefully, it gives the field a useful foundation to build on.”