Full-color flexible micro-LED devices are hot spots in the fields of wearable devices and vehicle displays. In previous studies, only blue and violet flexible micro-LEDs have been fabricated. In order to realize full-color display based on flexible micro-LEDs, it is necessary to study the method of realizing full-color display using color conversion technology.
In a study published in Micromachines, a research group led by Prof. LIANG Jingqiu from Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) of the Chinese Academy of Sciences (CAS) proposed flexible quantum-dot color-conversion layer (FQCL) based on microfluidics.
In this study, the structure of a full-color flexible micro-LED composed of flexible excitation light source and flexible color-conversion layer was studied. And a microfluidic-based FQCL was successfully fabricated. The fabrication process of FQCL includes fabrication of SU8 microchannel structure, fabrication of flexible microchannel layer and seal layer, flexible chip bonding, and injection of perovskite quantum dots (PQDs) solution.
The red and green PQDs synthesized by thermal injection have excellent quantum efficiencies as high as 51% and 90%, respectively. The full-color pixel pitch of the FQCL is 200 μm, and the number of pixels for an FQCL is 20×20. The color space coverage of a full-color flexible micro-LED composed of blue LEDs, red and green PQDs changed less than 4% after bending 1000 times. FQCL exhibited good display performance under different bending radii and bending times.
FQCL fabricated using microfluidics has the advantages of bendability, controllable size and shape, and economy. FQCL can promote the industrialization of full-color flexible micro-LEDs, and has considerable potential in wearable devices, vehicle displays, and electronic skins.