Inorganic perovskite nanocrystals exhibit many beneficial properties such as high defect tolerability, band gap tunability by composition and high photoluminescence quantum yield. While these properties are promising for optoelectronic applications, devices require an ordered, dense film of nanocrystals in order to facilitate efficient carrier transport.
Here, we explore an emulsion template to guide the assembly of inorganic perovskite nanocrystals. Since the nanocrystals are not stable in water, we use oil-in-fluorinated oil emulsions with the nanocrystals suspended in the regular oily phase. The oil (toluene) with nanocrystals is poured on top of the fluorinated oil with fluorinated surfactant and vortexed to obtain a stable emulsion. The oil is then slowly dried, leading to highly ordered superstructures, see Figure 1 below. Depending on the drying process and nanocrystals, we can achieve different morphologies superballs, supercubes and superhexagons, as shown in Figure 2.
Check out our paper in Nano Letters
