Water-repellent highly stable host material for colour conversion layer with enhanced quantum efficiency for micro-led display applications

Abstract

Micro-LED is emerging as a potential candidate for high-end display products with attractive properties like High contrast ratio, high resolution, small pixel size, longer life, wide colour gamut, the low power consumption etc. Two dominating methods for Micro-LED fabrication are mass transfer and colour conversion. Colour conversion can be achieved by colour converting materials such as quantum dots (QDs) or light-emitting polymers. More efficiency and light intensity can be achieved using this colour conversion technique as compared to the mass transfer technique. The colour conversion technique works with a GaN-based blue colour chip and we don’t require the other two-colour diode chips which will ultimately save time and production cost by avoiding mass transfer for the fabrication of Micro-LED. In this experiment, we evaluated organic dye for red (DCJTB) and green (C545T) emitters in a water-resistant, strong binder like PVB as a host material under different solvents resulting in rare-earth element-free fluorescent films. These polymers generally contain polyols that have long chains of carbon and can be extended into the solvent easily and they act as an anchoring group. PVB being water repellent helps in moulding the film with higher efficiency (~ 90%) and enhanced stability under normal and humid conditions, resolving the issue of device degradation in the presence of water content in the case of OLED. The synthesis process is very simple, cost-effective, and non-toxic.