Red light sensitive heterojunction organic field-effect transistors based on neodymium phthalocyanine as photosensitive layer

Abstract

Compared with organic photodiodes, photoresponsive organic field-effect transistors (photOFETs) exhibit higher sensitivity and lower noise. The performance of photOFETs based on conventional single layer structure is generally poor due to the low carrier mobility of the active channel materials. We demonstrate a high performance photOFET operating in red light with a structure of C60/neodymium phthalocyanine (NdPc2) planar heterojunction. PhotOFETs based on single-layer NdPc2 and C60/NdPc2 heterojunction (denoted as NdPc2-photOFETs and C60/NdPc2-photOFETs, respectively) were fabricated and characterized. It is concluded that the photOFETs with heterojunction structure showed superior performance compared to that of single layer photOFETs. And for red light with a wavelength of 655nm, C60/NdPc2-photOFETs exhibited a large photoresponsivity of ~0.8A/W, which is approximately 62 times larger than that of NdPc2-photOFETs under the same conditions. The high performance of C60/NdPc2-photOFETs is attributed to its high light absorption coefficient, high exciton dissociation efficiency and high carrier mobility.