Broad spectral response photosensitive organic field-effect transistors realized by the hybrid planar-bulk heterojunction composed of three molecules with complementary optical absorption

Abstract

Photodetectors have a growing number of diverse applications in both military and civilian use, and improving their response bandwidth is of great importance. Broad spectral response photosensitive organic field-effect transistors (PhOFETs) are realized by adopting hybrid planar-bulk heterojunction (HPBHJ) as the active structure that containing three molecules with complementary optical absorption. PhOFETs based on the HPBHJ composed of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA), chloroaluminum phthalocyanine (AlClPc) and C60, and SiO2 as the gate dielectric exhibit photo response in the broadband wavelength range of 300–850 nm. At an incident optical intensity of 0.07 mW/cm2, the mean photoresponsivity and uniformity factor were 0.40 A/W and 0.79, respectively. Furthermore, by replacing SiO2 gate dielectric with polyvinyl alcohol (PVA), the device performance could be further improved, the mean photoresponsivity was increased to 2.44 A/W. The physical origin of the performance improvement is discussed.