Quantum-Dot Photodetector Layers for Uniform Infrared Sensitivity

The patent applies parameter changes by systematically varying ligand types (L1 and L2 with different chemical structures as shown in Formulae (A) to (C)), quantum dot sizes, and composition ratios to optimize both sensitivity and in-plane uniformity. Specific ligand structures with different functional groups (thiol, amino, hydroxy, carboxy groups) are used to control quantum dot aggregation and electronic properties, achieving high sensitivity while reducing noise through parameter optimization

The patent uses composite materials by combining semiconductor quantum dots with specific ligands (L1 and L2) to create a heterogeneous structure. The photoelectric conversion layer contains quantum dots with ligand L1, while the hole transport layer contains quantum dots with ligand L2, forming a composite system that leverages the advantages of different material combinations to achieve both high sensitivity and uniformity

The patent replaces expensive InGaAs-based semiconductors requiring complex epitaxial growth with semiconductor quantum dots that can be synthesized using simpler, more cost-effective methods. The quantum dot-based photoelectric conversion layer achieves comparable or superior performance without the high manufacturing costs associated with epitaxial growth processes

The patent changes the material parameter from bulk InGaAs semiconductor to quantum dot structures, fundamentally altering the synthesis approach. By controlling quantum dot size, composition, and ligand environments, high external quantum efficiency is achieved through solution-based or simpler deposition methods rather than expensive epitaxial growth