The Synthesis And Properties Study Of Carbazole-functionalized Perylene Bisimides

Perylene bisimide compounds are a class of n-type materials of great importance,with large conjugate plane, high fluorescence quantum yield, excellent electrontransport properties and good light stability, thermal stability, chemical stability. Bysubstitution in different positions of perylene core and introduction of differentsubstituents to perylene core, new perylene bisimide compounds with adjustablecolors can be designed and synthesized. In recent years, perylene bisimidescompounds have been widely investigated on self-assembly functional materials,organic field-effect transistors, organic light-emitting diodes, organic solar cells andother fields.Carbazoles are commonly used as hole transport materials, which can formstable dimers through electrochemical polymerization and compounds with morecarbazole groups can form cross-linked structures by electrochemical polymerization.So we intend to introduce the electroactive carbazole to perylene bisimide in order toprepare stably cross-linked perylene bisimide films through electrochmicalpolymerization of carbazole group. We designed and synthesized a series ofcarbazole-functionalized perylene bisimides with different substituents in perylenecores. The structures of synthesized perylene bisimides were confirmed by NMR, MSand other characterization methods.We studied the optical properties and electrochemical properties ofcarbazole-functionalized perylene bisimide compounds. The compounds show the ability to form domain-like thin layer on ITO through electrochemical coupling ofperipheral carbazoles. Such domain-like ultra-thin layers are highly cross-linked inchemical structure (insoluble in any solvents), and strongly electrophilic in electronicstructure, exhibiting a potential as electron collection layers in inverted photovoltaiccells. The controlled domain-density of cross-linked particles on ITO has beenrealized through varied CV scanning cycles. Inverted polymer solar cells (PSCs)prepared by spin-coating an PCDTBT:PC71BM (90nm as active layer) on domainlayer modified ITO (as electron-collection layer) exhibit increased power conversionefficiency. Our results show that perylene bisimide derivatives are promisingcandidates for the modification of the electrodes by ECP method.