Charge transport behavior at donor/acceptor interface aimed at high electrical conductivity with suppressed activation energy

This study focuses on the donor–acceptor interface composed of 4,4′,4″-tris[phenyl(m-tolyl) amino]triphenylamine (m-MTDATA) and copper(II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine (F16CuPc) layers. Due to the charge transfer characteristics at the interface of the m-MTDATA (30 nm)/F16CuPc (30 nm) layers, a high electrical conductivity as high as 10−4 S cm−1 was achieved. Our findings indicate that the dominant current transport layer originates from F16CuPc with a CT depth of ∼3 nm from the donor–acceptor interface. Furthermore, the formation of dual interfaces of donor–acceptor–donor layers, i.e., m-MTDATA (30 nm)/F16CuPc (5 nm)/m-MTDATA (30 nm), appreciably reduced the activation energy for charge transport, i.e., Ea = 0.183 eV in the three-layer structure and Ea = 0.239 eV in the two-layer structure, respectively.