We investigate the behavior of evaporative crystallization of a fluorescent dye droplets on the substrates with different contact angles. Evaporation of the dye drop lead to smaller crystals at the centre of the droplet. In the case of on the glass substrate, two distinct microcrystalline morphologies of the recrystallized deposits – hexagonal and stick/rod shaped have been observed. This indicates that the evaporation driven crystallization is highly dependent on the wettability of the substrate. The sizes of crystals decrease on increasing the contact angle of the substrate. The photoluminescence (PL) studies indicate that the hexagonal crystals have higher emission compared to rod-shaped crystals. PL decay measurements also show distinct lifetimes for the two shapes. The self-assembly leading to the formation of distinct crystal morphologies along with their individual optical properties different from the parent material is highly interesting to the optical materials research.

我们研究了具有不同接触角的基底上的荧光染料液滴的蒸发结晶行为。染料滴的蒸发导致液滴中心的晶体变小。在玻璃基板上，已观察到重结晶沉积物的两种不同的微晶形态-六角形和棒/棒状。这表明蒸发驱动的结晶高度依赖于基材的润湿性。晶体的尺寸随着基板的接触角的增加而减小。光致发光（PL）研究表明，六方晶体比棒状晶体具有更高的发射。PL衰减测量还显示了这两种形状的不同寿命。