Effect of core-substituted groups on sensing properties based on single micro/nanorod of perylenediimide derivatives

Three perylenediimide derivatives PTCDI-Br2C10, PTCDI-C10 and PTCDI-BP2C10 were prepared in order to probe the effect of core-substituted groups on their sensing properties. The determination of sensing properties based on their conductometric gas sensors composed of single micro/nanorod revealed that the current increased was one order of magnitude higher for core-henoxy-substituted PTCDI-BP2C10 and lower for core-brominated PTCDI-Br2C10 than that of core-unsubstituted PTCDI-C10 in hydrazine vapor (10 ppm). The differential response to the hydrazine vapor for the PTCDI-Br2C10 and PTCDI-C10 gas sensors was independent of their surface area and morphologies, and was ascribed to twisted skeleton of the PTCDI-Br2C10 molecule that derived from non-bonded repulsions between bromines that lied in bay-area. Whereas a lower activation energy level and a larger delocalized system efficiently made up for deficiency for carriers transport that arising from the distorted skeleton of perylene units and leaded to one order of magnitude in current increased higher for PTCDI-BP2C10 compared to that of PTCDI-C10. Discussions for structure-function relationships suggested that core-substituted groups had significant impact on the performance of PTCDIs gas sensing devices by modulating band gap and structure of skeleton.