Gold Nanoparticles-Decorated N,N'-dioctyl-3,4,9,10-perylene Tetracarboxylic Diimide Active Layer Towards Remarkably Enhanced Visible-Light Photoresponse of an N-Type Organic Phototransistor

Metal nanostructures exhibit distinct physical properties from macroscopic objects, which have been widely applied to organic optoelectmnic device. N, N'-dioctyl-3,4,9,10-perylene tetracarboxylic diimide (PTCDI-C8) is one of the few air-stable, high mobility n-type semiconductor, which is usually used to fabricate green or white light detectors due to its main absorption concentrated in the range 450 - 600 nm. In this paper, a high performance red light sensor was achieved by PTCDI-C8 based organic phototransistor (OPT) with the optimized gold nanoparticles (AuNPs) modified layer, the photosensitivity, photoresponsivity, specific detectivity and the external quantum efficiency (EQE) of which can reach 6.21 x 10(5), 24.12 A/W, 2.85 x 10(11) Jones and 453.58% at 660 nm, respectively. Additionally, the AuNPs-modified OPT also gained a significant improvement in EQE under green light illumination at 532 nm compared with single PTCDI-C8 layer OPT. The photophysical mechanisms of introducing AuNPs to improve device performance were explored.