Ultrafast Dense DNA Functionalization of Quantum Dots and Rods for Scalable 2D Array Fabrication on DNA Origami with Nanoscale Precision

Quantum dots (QDs) and quantum rods (QRs) have attracted extensive interest in next-generation display systems due to their bright and tunable narrowband photoluminescence (PL). Moreover, QDs are also key candidates for quantum computing, quantum sensing, and quantum metrology through integrated quantum photonics. Scalable fabrication of QD/QR arrays possessing controlled spacing and orientation with nanometer precision on a device substrate is essential to the advancement of such research and applications. DNA origami technology has offered a scalable bottom-up strategy to organize nanoparticles at the nanoscale with unparalleled programmability and versatility. However, multiplexing QDs and QRs with DNA origami structures has been challenging, primarily due to the low DNA conjugation density to QDs/QRs from existing methods, which often leads to poor colloidal stability and low binding efficiency. Here, we developed an ultrafast strategy to prepare high-density DNA functionalized QDs/QRs (0.17–0.21 DNA per nm²) directly from their organic solution using a dehydration and rehydration process that reduces the fabrication time from hours to a few minutes. As prepared QDs/QRs were stable in a range of buffer conditions and able to hybridize to DNA origami structures with excellent efficiency and precision. To fabricate QD/QR arrays, we further developed a Surface-Assisted Large-Scale Assembly (SALSA) method to construct 2D origami lattices directly on a solid substrate for QD/QR temptation, which circumvents problems in transferring solution-assembled soft 2D materials to a device surface. We designed a 6-helix-bundle (6HB) rhombic-shaped wireframe origami structure with high structural fidelity, planarity, and rigidity. With unique anisotropic crossover designs between neighboring origami structures, 2D origami lattices up to micrometer scale were produced by tuning origami surface diffusion, hybridization error correction and landing face selection. QDs and QRs were then assembled to the origami lattices with precisely controlled positions, inter-particle distances and orientations, with a loading yield over 90%. We further fabricated a monolayer QR array with aligned QR orientations, which can function as a polarized light source due to the PL emission anisotropy along the long axis of QRs and their alignment on surface. Our approaches can enable scalable fabrication of DNA-programmed QD and QR devices with nanoscale orientation and positioning accuracy for advanced applications in display, sensing and photonics.