Synthesis of a metal-organic framework film by direct conversion technique for VOCs sensing

For the first time, a metal-organic framework Zn-3(BTC)(2) film has been successfully synthesized on the substrate of zinc wafer by a direct conversion technique. The obtained crystal densities and inter-growth of the film have been improved via the zinc wafer conversion method. The effect of synthesis conditions on the crystallization of Zn-3(BTC)(2) and activation of the substrate were determined to optimize the strategies for the synthesis of continuous and stable layers. The crystallization took place by converting the activated zinc layer on the substrate. The reaction between the substrate-generated zinc source and the H3BTC clear solution yielded the best inter-growth of crystals and formed a high-density coating. More interestingly, the fluorescence emission of the Zn-3(BTC)(2) film was found to be highly sensitive and selective sensing to dimethylamine among different VOCs. The fluorescence intensity decreased with increasing contents of dimethylamine in ethanol solution due to weak fluorescence quenching effect. This high-quality MOF film may find promising applications in sensors, especially in VOCs sensing.