Advanced manufacturing of microscale light-emitting diodes and their use in displays and biomedicine

Thin-film, microscale light-emitting diodes (micro-LEDs)-based III–V compound semiconductors are emerging as a promising technology for next-generation light sources with various applications including lighting, display and biomedicine. With this perspective, we provide an overview and highlight our own progress on the recent developments in advanced manufacturing techniques and potential applications of micro-LEDs. The combination of epitaxial lift-off and transfer printing techniques have produced ultraminiaturized, highly luminous, and energy-efficient thin-film micro-LEDs, with a wide range of applications. To achieve full-color displays, several approaches have been developed, including horizontally and vertically assembled red-green–blue (RGB) pixels, and quantum dot conversion. For neuroscience studies, these micro-LEDs can be integrated in flexible probes as implantable light sources, which facilitate light delivery into the deep brain tissue for optogenetic stimulations and biological sensing. Additionally, micro-LEDs have the potential to function as wireless biosensors to detect changes in the biological environment, through their luminescence or in combination with other devices. Overall, advanced manufacturing techniques produce micro-LEDs that promise significant applications not only in displays but also in various biomedical fields.