Photocleavable Ligand-Induced Direct Photolithography of InP-Based Quantum Dots

Direct photolithography, which utilizes photosensitive quantum dot (QD) inks, is a powerful patterning method for implementing next-generation high-resolution QD displays. However, the chemical reactions occurring during the photoinduced solubility change process can damage the QDs’ surface, especially for InP QDs. In this study, we focus on a cleavable ligand-induced direct photolithography (CLIP) technique utilizing specially designed 3-((but-3-enoyloxy)methyl)-2-nitrobenzoic acid (BNA) ligands. The BNA ligand, composed of a carboxylic acid and an ortho-nitrobenzyl ester, facilitates ligand exchange and photocleavage reactions and induces a significant solubility difference upon ultraviolet (UV) irradiation, enabling patterning at a low UV dose while maintaining 75% of the original photoluminescence quantum yields of InP/ZnSe/ZnS QDs. This method can generate high-resolution, multicolor patterns while enhancing electrical conductivity after the patterning process, making it suitable for QD light-emitting diodes (LEDs). Our study represents a pioneering effort in CLIP for InP core/shell QDs, which could also be widely applicable to colloidal nanomaterials and devices.