Vapor-assisted epitaxial growth of porphyrin-based MOF thin film for nonlinear optical limiting

Fabrication of metal-organic frameworks (MOFs) thin films has been an efficient way to expand their functionalities and applications. Here, we use the vapor-assisted deposition (VAD) method to epitaxially grow a porphyrin-based MOF PCN-222 film. That is, vapor source assists to deposit pre-treated precursor solution on quartz substrate to form a continuous PCN-222 film. Furthermore, utilizing the post-treated encapsulation of functional carbon-based nanoparticles, the carbon nanodots (CND) and Pt doped CND (Pt/CND) are well loaded into the pores of PCN-222 film, the size (similar to 3.1 nm) of which is highly close to the pore size of the corresponding MOF (similar to 3.7 nm). The Z-scan results reveal that PCN-222 film exhibits high reverse saturable absorption. In addition, encapsulation of carbon based nanodots into PCN-222 film could enhance the nonlinear optical limiting effect benefiting from the host-guest combination. This study serves to present both the available toolbox of thin film preparation and high potential for precise synthetic nanocomposite films in optical limiting devices.