Efficient p‐Doping with F6TCNNQ for Improving Performance of Polymer Photodetectors with Photomultiplication

Abstract

Polymer photodetectors with photomultiplication (PM‐PPDs) are prepared with PC71BM:P3HT (1:100, wt/wt) active layers containing efficient hole‐transport channels and large amount of isolated electron traps. The solid additive F6TCNNQ is incorporated into PC71BM:P3HT blend films with rather low content of 0.02 wt%. The external quantum efficiency (EQE) and response speed of PM‐PPDs with F6TCNNQ additive in the active layer are much larger than those of PM‐PPDs without F6TCNNQ additive under the same bias. The EQE values at 400 and 625 nm can reach 5240% and 3050% for the PM‐PPDs with F6TCNNQ in active layers under −9 V bias, which is among the highest values for PM‐PPDs under the same bias. The performance improvement of PM‐PPDs with F6TCNNQ is primarily ascribed to the enhanced hole mobility in the active layer, leading to the increased response speed with rise time of 27.7 ms and fall time of 85 ms. This work indicates that performance of PM‐PPDs can be markedly enhanced by using p‐doping with strong oxidizing agents, beneficial for an enhancement in hole mobility in F6TCNNQ:PC71BM:P3HT active layers.