Probing the sensory property of perylenediimide derivatives in hydrazine gas: core-substituted aromatic group effect

In this contribution, four perylenediimide derivatives (PTCDIs) with different core-substituted aromatic groups were prepared. Studies on their sensing properties in hydrazine vapor (10 ppm)  suggested ∼5 orders of the magnitude in increased current for core-phenyl-substituted DEY was achieved and this value is 9, 9, and 24 times higher than that of core-pyridyl-substituted DSPY, DFPY, and DTPY, respectively. The differential response to the hydrazine vapor is less dependent on their surface area and morphologies. The lower LUMO energy and activation energy with smaller interplanar spacing allows DEY highly efficient sensing performance. A similar face-face packing mode and LUMO energy of DSPY and DFPY lead to both of them exhibiting the same sensing performance, while higher LUMO energy and head-to-tail packing modes with a greater interplanar spacing induce the less-efficient sensing performance of DTPY sensors. Discussions for structure-function relationships suggested that aromatic groups in the bay region have significant impact on PTCDI sensing performance by modulating energy level, interplanar spacing, and stacking modes.