Student; Researcher UCLA Los Angeles, CA, United States
Flexible, bright, and high-resolution displays have gained significant attention in the past decades and are expected to play significant roles in applications ranging from Human-Machine interface devices to the medical fields. In recent years, microLED technology has gained significant traction in the effort to enable high throughput manufacturing processes for efficient micro-displays. [1] This technology is based on inorganic III-V materials grown on native substrates using MOCVD or MBE. [2] Then, it is transferred onto its final device substrate or panel using laser liftoff with roll to roll printing or other methods of transfer. These devices have many advantages including increased emission brightness, improved external quantum efficiency, and superior device lifetime over OLED and LCD technologies [3]. We present such a display fabricated on a flexible substrate using FlexTrateTM with high pixel density along with all the previously stated performance improvements and demonstrate the conversion from a single-color LED to other colors using quantum dots. We integrate quantum dots directly onto our flexible display by fabricating a flexible scaffold structure directly atop the LED arrays after mass transfer with LLO (with the LEDs sitting on our secondary substrate). Then, we dispense colloidal quantum dots within the wells formed by our scaffold structures before dispensing PDMS then transferring both the microLEDs and the quantum dot structure to our final flexible substrate. Benefits of this approach include much reduced optical crosstalk between neighboring subpixels and reduced quantum efficiency losses as a function of distance in terms of the re-emission of photons from the initial microLEDs through the quantum dots. In our presentation of this work, we also demonstrate the progression of our display from previous iterations in terms of throughput, reliability, and process improvements with regards to our current display fabrication process.