Researchers from Seoul National University developed an ultrathin QLED device, that can be folded just like a paper. The researchers demonstrated a 3D foldable QLED, which can be produced in customized 3D structures.
To produce the device, the researchers developed a new fabrication process, that can partially etch the epoxy film deposited on the QLED surface without damaging the underlying QLED. This changes the QLED film from a planar shape to the 3D foldable shape.
Using a power-controllable carbon dioxide pulsed laser and silver-aluminum alloy-based etch-stop layers, the etching depth can be precisely controlled. The parts which are etched are thinner, and can thus be folded. Based on the selective laser-etching technique, researchers were able to precisely control the radius of curvature down to less than 50 micrometers.
The QLED device, including the fold line, was able to maintain a stable light-emitting performance even 500 folding cycles.