Researchers from ETH Zürich and the Huazhong University of Science and Technology developed a new scalable fabrication technology that enables the deposition of extremely small OLED pixels. The so-called nano-OLEDs achieve a pixel density of 84,000 PPI, or even higher. The pixel size is around 100 nm, the smallest pixels ever reported.
The method is based on direct nanomolecular patterning of the OLED materials, realized by self-aligned evaporation through nanoapertures fabricated on a free-standing silicon nitride film adhering to the substrate. The researchers report that the average nano-OLED EQEs is up to 10%.
The researchers further say that at the subwavelength scale, individual pixels act as electroluminescent meta-atoms forming metasurfaces that directly convert electricity into modulated light. The diffractive coupling between nano-pixels enables control over the far-field emission properties, including directionality and polarization.
