Fig. 1: Nanoprinting of perovskite QDs by EFASP.
From: High-resolution combinatorial patterning of functional nanoparticles
a Schematic illustration of the EFASP process, which involves high-voltage electrostatic nanopattern generation, surface modification, and site-specific NP assembly by electrical trapping. b Electrical trapping potential in a nonpolar solvent as a function of the distance from the center of the written charge (dash circle 1 in a). The electric fields can extend for hundreds of nanometers, leading to the high efficiency of NP collection. c Surface potential modulation along the nanopattern surface (dash circle 2 in a) De-fluorination through high voltage induces significant surface energy modulation, providing strong short-range interactions to fix the NPs. d A large-scale photoluminescence (PL) image obtained by assembling CsPbBr3 NPs using the EFASP process, with a total area of 100 × 800 μm2 with 9481 pixels, a pitch of 800 nm, and approximately 4.7 × 105 10-nm CsPbBr3 NPs. Scale bar, 50 μm. e High-magnification PL, SEM, and AFM height images of the marked area in d. Scale bar, 2 μm. f–i Extremely high-resolution EFASP can be produced by modulating patterns, reaching a pitch of 200 nm (125,000 DPI). The high-magnification KPFM potential map and corresponding AFM height map after NP assembly (f and h, scale bar: 2 μm) and their details (g and i, scale bar: 500 nm). The corresponding large area PL image is shown in Supplementary Fig. 2.
