Organic Thin Film Transistor Material Based Photomultiplication Type Organic Photodetectors via Balancing Hole Tunneling Injection and Transport

Abstract Photomultiplication type organic photodetectors (PM‐OPDs) are prepared with organic thin film transistor (OTFT) material PC12TV12T as donor and PC 71 BM as acceptor, the optimal weight ratio of PC12TV12T to PC 71 BM is about 100:7. The external quantum efficiency (EQE) of optimal PM‐OPDs is 9200% at 370 nm under ‐8 V bias, resulting from the hole tunneling injection induced by trapped electrons in PC 71 BM surrounded by PC12TV12T near Al electrode. P3HT is deliberately selected as the third component due to its high absorption coefficient and the lowest unoccupied molecular orbital. The optimal ternary PM‐OPDs exhibit the EQE and specific detectivity ( D* ) of 12600% and 7.63 × 10 11 Jones at 370 nm under ‐8 V bias. Meanwhile, the signal‐to‐noise (SNR) of PM‐OPDs can be increases over twenty times by employing P3HT as a third component, benefiting from the markedly decreased dark current density. This work indicates that PC12TV12T used in OTFT should be an excellent host material for achieving PM‐OPDs, benefiting from its high mobility and appropriate energy level.