Synthesis of a Perylene Diimide Dimer with Pyrrolic N–H Bonds and N‐Functionalized Derivatives for Organic Field‐Effect Transistors and Organic Solar Cells

This study reports on the new and optimized synthesis of an N-annulated perylene diimide dimer with functional N-H moieties. The presence of two N-H moieties renders the dimer relatively insoluble in most organic solvents. The dimer is easily functionalized with electron donating hexyl chains or electron withdrawing tert-butyloxycarbonyl (tBOC) groups to yield highly soluble materials. The tBOC groups can be thermally cleaved in the thin film to give the parent dimer. The N-H bonds are acidic and interact with volatile organic bases. Deprotonation results in a color change from red to blue. All compounds have utility as electron transport materials in organic field-effect transistors and green solvent, air processed organic solar cells. Electron mobilities were on the order of about 2-7x10(-6) cm(2)/Vs. Solar cell power conversion efficiency reached 2% for those using the tBOC functionalized dimer, 3% for those using the H-atom functionalized dimer, and 6% for those using the hexyl chain functionalized dimer. The performance of the latter is quite impressive considering the simple materials synthesis and greener solar cell processing.