High performance ternary organic photomultiplication detectors based on non-fullerene acceptor ITIC

Abstract

To extend response spectrum to near infrared region, one non-fullerene acceptor ITIC was doped into P3HT:PC₆₁BM blends, and the organic photomultiplication detectors (OPMDs) with structure of ITO/PEDOT:PSS/P3HT:ITIC:PC₆₁BM(100:x:1, wt/wt/wt)/Al were prepared. The absorption and photoluminescence spectra of the active layer films and the current density-voltage characteristics of the devices were measured and analyzed, and the photomultiplication principle of the devices was studied. The results showed that a wide spectral response of 400–850 nm is realized in the ternary P3HT:ITIC:PC₆₁BM active layer, and the external quantum efficiency, responsivity and specific detectivity of the ternary OPMDs based on P3HT:ITIC:PC₆₁BM are all larger than those of the binary ones based on P3HT:PC₆₁BM, and a maximum external quantum efficiency of 1113.71 %, specific detectivity of 6.42 × 10¹³ Jones and photoresponsivity of 762.99 A/W are obtained at 850 nm and under −16 V bias when the ITIC mass ratio in the ternary active layer is 4 % (i.e., x = 4). Such a considerable performance can be due to the fact that doping ITIC into P3HT:PC₆₁BM can widen absorption spectrum of active layer to near infrared area, and increase electron trap density and exciton dissociation interfaces in active layer and create cascade energy levels for better carrier transport.