Fabrication of polymer thin films with in-depth dye-dispersed structures by the vacuum spray method

We report the fabrication of polymer thin films with “in-depth” dye-dispersed structures using a vacuum spray method. Copper (II) 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine [(t-Bu)4CuPc] and polycarbonate in chloroform solution were sprayed onto the substrate. The (t-Bu)4CuPc distribution was controlled precisely during thin film growth by varying its concentration in the solution. Uniform, bilayer, and gradient structures of (t-Bu)4CuPc dispersed in thin films were confirmed by high-angle annular dark field imaging on scanning transmission electron microscopy. The vacuum spray method has several advantages compared to the casting method, such as smaller dispersed dye-aggregates and lack of cavities due to air bubbles.