Quantum Dot Ink Chemistry for Uniform Display Film Deposition

The patent introduces a ligand exchange mechanism as an intermediary process. The original ligands on quantum dot surfaces are replaced with new ligands that have specific functional groups capable of strong interaction with the substrate. This intermediary chemical transformation enables uniform deposition by preventing the quantum dots from aggregating or migrating during the drying process, thus resolving the contradiction between achieving wide color gamut and maintaining film-forming uniformity.

The patent changes the chemical parameters of the ligands coordinating on quantum dot surfaces. By selecting ligands with specific functional groups (such as carboxylic acid, phosphine, or thiol groups) that have appropriate binding affinity to the substrate, the deposition behavior of quantum dots is controlled. This parameter change in ligand chemistry prevents Marangoni effect and coffee-ring effect, achieving uniform film formation while preserving the optical properties for wide color gamut.

The ligand acts as an intermediary that mediates between the quantum dot body and the substrate. During the drying process, the ligand's functional groups form strong chemical bonds with the substrate while maintaining quantum dot dispersion. This intermediary bonding mechanism prevents the quantum dots from being swept to the edges by capillary forces (coffee-ring effect) or from climbing up the meniscus (climbing phenomenon), ensuring uniform deposition across the substrate.

The patent applies preliminary anti-action by pre-modifying the quantum dot surface with specific ligands before deposition. These ligands are selected to counteract the harmful effects of Marangoni convection and capillary forces during drying. The ligand shell provides steric stabilization and chemical anchoring that prevents the quantum dots from migrating during the drying process, thereby preventing poor film-forming uniformity before it occurs.