Direct Optical Patterning of Colloidal InP-based Quantum Dots Using Photoacid Generators

Direct optical patterning of colloidal nanomaterials has recently received a lot of attention because of photoresist-free simple patterning procedure. The use of photoacid generator (PAG) additive has been studied as one of the promising approaches for direct optical patterning of colloidal quantum dots (QDs). With PAG, high-resolution QD patterning without complete ligand exchange is enabled. However, direct optical patterning of QDs with PAG may result in decrease in photoluminescence quantum yield (PLQY) in case of insufficient surface passivation of patterned QDs. Furthermore, such PLQY decrease could be enhanced for colloidal InP-based QD, which has high oxophilicity. Therefore, systematic and fundamental studies to achieve high-resolution InP-based QD patterns while minimizing the surface damage are required. Here, we show high-resolution direct optical patterning of InP-based core/shell QDs using a triazine-based photoacid generator. We investigate the changes in optical and structural properties of the core/shell QDs with each patterning step. Also, our study involves ligand post-treatment for the PLQY recovery of patterned InP QDs. The post-treatment passivated the surface defects and thereby increased the PLQY of InP QDs by ~90%. We believe our study suggests a facile way of patterning air-sensitive colloidal nanomaterials for various electronic and optoelectronic applications.