Photomultiplication type all-polymer photodetectors with single carrier transport property

Abstract

Photomultiplication (PM) type all-polymer photodetectors (all-PPDs) are first demonstrated with the sandwich structure of ITO/PEDOT:PSS/PBDB-T:PZ1 (100: x , wt/wt)/Al. The optimal PM type all-PPDs with PBDB-T:PZ1 (100:3, wt/wt) as active layers exhibit external quantum efficiency (EQE) of >100% in the spectral range from 310 to 790 nm. Under 675 nm light illumination, the champion EQE value arrives to 1,470% at −20 V bias and the specific detectivity approaches 1× 1012 Jones at −10 V bias. The PM phenomenon in all-PPDs results from hole tunneling injection assisted by interfacial band bending induced by trapped electrons in PZ1 near Al electrode. The EQE values of optimal PM type all-PPDs still remained over 90% of the original value after 60 d of the storage in a high-purity nitrogen-filled glove box.