Recently, SEOULTECH researchers developed a graphene-based laser separation technique that prevents damage during separation of ultra-thin OLED displays. By utilizing graphene’s ultraviolet light absorption and heat dispersion capabilities, they have achieved pure and flexible displays. This advancement will revolutionize wearable technology by enabling ultra-thin stretchable devices that fit comfortably against human skin.
As the demand for thinner, lighter and more flexible electronics increases, the need for advanced manufacturing processes is urgent. Polyimide (PI) films are widely used in these applications due to their excellent thermal stability and mechanical flexibility. They are crucial for emerging technologies such as rollable displays, wearable sensors and embedded photonic devices. However, traditional laser lift-off (LLO) techniques often fail when the thickness of these films drops below 5 μm. Mechanical deformation, wrinkles and residues often reduce the quality and functionality of ultra-thin devices, leading to inefficient processes and high costs.
In this regard, researchers turned to graphene, a nanomaterial known for its excellent thermal and mechanical properties. A research team led by Professor Sumin Kang of Seoul National University of Science and Technology (SEOULTECH) designed a new technique to overcome the challenges of the LLO process. Their innovative graphene-assisted laser elevation (GLLO) method allows for smooth and damage-free removal of ultra-thin displays, making them ideal for wearable applications. Their research was published in the journal Nature Communications on September 27, 2024 .
In this study, they introduced a novel GLLO process to integrate graphene layers grown by chemical vapor deposition between a PI film and a glass carrier. ” Graphene’s unique properties, such as its ability to absorb ultraviolet (UV) light and distribute heat horizontally, allow us to cleanly peel off thin substrates without leaving any wrinkles or residues, ” said Prof. Kang. Using the GLLO method, the researchers successfully separated an ultrathin PI substrate with a thickness of 2.9 μm without mechanical damage or leaving any carbon residues. In contrast, traditional methods wrinkle the substrate and make the glass carrier unusable due to stubborn residues. This breakthrough has far-reaching implications for stretchable electronics and wearable devices.
The researchers further demonstrated the potential of the GLLO process by creating organic light-emitting diode (OLED) devices on ultrathin PI substrates. GLLO-processed OLEDs maintain their electrical and mechanical performance, exhibiting consistent current density, voltage, and luminance characteristics before and after takeoff. These devices can withstand extreme deformations, such as bending and twisting, without compromising their functionality. Additionally, carbon residues on the glass carriers were reduced by 92.8%, enabling their reuse. These findings highlight GLLO as a promising method to fabricate ultrathin, flexible electronic devices with improved performance and reduced cost.
” Our method brings us closer to a future where electronics are not only flexible but also seamlessly integrated into clothing and even skin, improving both comfort and functionality,” said Kang. Using this method, it could be easy to design flexible devices capable of real-time monitoring, rollable smartphones, and health trackers that bend and stretch with our movements.
Going forward, the team plans to further optimize the process, with a focus on completely eliminating residues and improving scalability. The GLLO process has the potential to revolutionize the electronics industry, marking a major step towards a future where ultra-thin, flexible, high-performance devices become an everyday option.
