Alkylsilane-functionalized perylenediimide derivatives with differential gas sensing properties

Abstract

In this investigation, four perylenediimide derivatives (PTCDIs) with different lengths and branched points of alkyl chains on bay region were prepared to probe the effect of alkyl chains on sensing performance. Studies on the sensing properties of these derivatives in hydrazine vapor revealed that an increased current of about 4 orders of magnitude was achieved for TPSA. This value is ca. 2, 2 and 23 times higher than that of DMB, TMSA and TESA, respectively. The differential response of these PTCDIs gas sensors to the hydrazine vapor is not much dependent on their surface area and morphologies. A well-ordered layer structure with smaller interplanar spacing endows TPSA with a highly efficient sensing performance. A similar face–face packing mode and torsional angle of DMB and TMSA cause both of them to exhibit almost same sensing performance, in spite of the differences in their interplanar spacing. However, a greater torsional angle and head-to-tail aggregated modes with greater interplanar spacing induce a less efficient sensing performance of TESA sensors. This study indicates that the length and branched point of alkylsilane on the bay region have significant impact on the performance of PTCDIs gas-sensing devices because they can modulate torsional angle, interplanar spacing and stacking modes.