Nondestructive High-Resolution Direct Optical Lithography of Colloidal Emissive Nanocrystals

High-resolution precision patterning is a crucial requirement in the fabrication of immersive near-eye displays that incorporate high-color-purity emissive nanocrystals such as colloidal quantum dots and perovskite nanocrystals as color filters or electroluminescence (EL) emission layers in the form of an RGB matrix.¹⁾ Direct optical lithography, which involves a photochemical reaction of photosensitive ligands or additives, offers a new platform for patterning colloidal nanocrystals, providing high pattern uniformity with a simple procedure.²⁾ However, a significant decrease in photoluminescence (PL) quantum yield during the patterning process has been a major challenge. To address this challenge, we have developed direct, scalable, and nondestructive methods for high-resolution patterning of colloidal emissive nanocrystals without sacrificing their luminescent properties. With photochemically activated reactions, leading to <i>in situ</i> exchange^3-4) or crosslinking⁵⁾ of long-chain organic ligands, we have demonstrated uniform PL and EL patterns of red, green, and blue quantum dots and perovskite nanocrystals with feature sizes as small as sub-1 µm, while preserving their structural, electronic, and emissive properties. The underlying patterning mechanisms were identified by investigating the photochemical transformations of surface ligands and additives at each step of the process. Our approach provides a promising solution for patterning of colloidal emissive nanocrystals, which can be implemented in next-generation augmented reality displays and other optoelectronics applications.<br/> <br/><b>References</b><br/>1) <i>Advanced Materials Technologies</i> 2022, 2201070<br/>2) <i>Accounts of Chemical Research</i> 2023, 56, 17, 2286<br/>3) <i>Advanced Materials </i>2020, 32, 2003805<br/>4) <i>ACS Energy Letters </i>2023, DOI: 10.1021/acsenergylett.3c01019<br/>5) <i>Science Advances</i> 2023, 9, eadi6950