Downscaling micro- and nano-perovskite LEDs

Many technological breakthroughs in electronics and photonics were made possible by downscaling – the process of making elementary devices smaller in size1-5. The downsizing of light-emitting diodes (LEDs) based on III-V semiconductors led to micro-LEDs5-12, an ‘ultimate technology’ for displays. However, micro-LEDs are costly to produce and they exhibit severe efficiency losses when the pixel sizes reduce to ~10 μm or below, hindering their potential in commercial applications. Here, we show the downscaling of an emerging class of LEDs based on perovskite semiconductors to below the conventional size limits. Micro- and nano-perovskite LEDs (micro/nano-PeLEDs) with characteristic pixel lengths from hundreds of μm down to ~90 nm are demonstrated, through a localised contact fabrication scheme that prevents nonradiative losses at the pixel boundaries. For our near-infrared and green micro-PeLEDs, average EQEs are maintained at around 20% across a wide range of pixel lengths (650 to 3.5 μm), exhibiting minimum performance reduction upon downsizing. Our nano-PeLEDs with characteristic pixel lengths of down to ~90 nm represent the smallest LEDs reported, enabling a record-high pixel density of 127,000 pixels per inch (PPI) amongst all classes of LED arrays. Our demonstration showcases the strength of micro/nano-PeLEDs as a next-generation light source technology with unprecedented compactness and scalability.