Impact of alkyl side chains at self-assembly, electronic structure and charge arrangement in sexithiophene thin films

摘要: Abstract The energy-level alignment of vacuum-sublimed thin films a series differently alkyl-substituted sexithiophenes (6T) ( α , ω -didecylsexithiophene (DD6T), -diethylsexithiophene (DE6T) and 3′,4′-dimethyl- -dihexylsexithiophene (Me-DH6T)) on Ag(1 1 1) substrates was investigated by means ultraviolet photoelectron spectroscopy (UPS). orientation dependent ionization energy the 6T derivatives allowed determining film growth mode molecules, which varied with length substitution-position alkyl chains conjugated backbone. DE6T Me-DH6T are lying almost flat in monolayer multilayers, whereas DD6T undergoes an orientational transition from to standing second molecular layer onwards. Additional UPS experiments high work function substrate, i.e., pre-covered tetrafluoro-tetracyanoquinodimethane, illustrate how slight shift center-of-mass molecule’s electron density might lead (in contrast charge transfer) interface dipoles at organic–organic interfaces thus Fermi-level pinning such interfaces.