Ambipolar charge-transport property for the D–A complex with naphthalene diimide motif

Abstract

A new naphthalene diimide (NDI) derivative 4NH₂-NDI was synthesized and investigated. The introduction of four amino groups at core position endows 4NH₂-NDI with a high HOMO energy (−4.87 eV). The organic field effect transistor (OFET) results reveal that 4NH₂-NDI behaves as a p-type semiconductor with a rather low hole mobility of 8.2 × 10⁻⁵ cm² V⁻¹ s⁻¹. However, its hole mobility can be enhanced significantly after doping with N,N-dihexyl naphthalene diimide (DHNDI). More interestingly, the blend thin films of 4NH₂-NDI and DHNDI exhibit ambipolar behavior based on the respective transfer and output characteristics measured in an inert atmosphere, and hole and electron mobilities can reach 0.01 cm² V⁻¹ s⁻¹ and 0.001 cm² V⁻¹ s⁻¹, respectively, when the molar ratio of 4NH₂-NDI and DHNDI is 1 : 3.