Controlled ultrasonic nebulization: A physical vapor deposition variant for low temperature and low growth rate of small molecule thin films

Ultrasonic nebulization is explored here as a resourceful technique for ultrathin film production technique for small molecules. The method can be employed over a variety of substrates, particularly with low viscosity solvents such as water. Specifically for water, spin coating is nearly prohibitive for molecules with a molecular weight up to 1 kDa. However, there is a lack of quantitative results on the ultrasonic nebulization technique when used for deposition in mild conditions that result in film growth. In this work, we study this growth technique to produce ultrathin films of perylenetetracarboxylate derivatives over silica and hexagonal boron nitride flakes. The morphology and physical characteristics of our films were evaluated using atomic force microscopy (AFM) and photoluminescence (PL). A physicochemical model is proposed to explain the overall shape of the height distribution of the films as exponentially-modified Gaussian functions.