Schematic illustration of the nanocrystal synthesis process. (i) Asymmetrically wetting template consisting of the non-wetting top surface and wetting well interior is fabricated using lithographic patterning of HSQ and selective surface treatment with fluorinated molecular assembly. (ii) CsPbBr 3 precursor solution is drop-casted on the template. (iii) Excess solution is spun off of the template, leaving precursor solution localized in the wells. (iii-1) In each well, the solution forms a meniscus with a contact angle theta to the side walls. As the solvent evaporates, a nanocrystal nucleates in the well and continues to grow. The local variation in meniscus height delta results in a pressure gradient, leading to a force ( F ) directed from the highest ( P 0 ) to lowest ( P 1 ) pressure region which helps guide nanocrystal positioning. (iv) Upon complete solvent removal through the evaporation process and an annealing step, the nanocrystal formation is complete.
