Broadband photomultiplication-type polymer photodetectors and its application in light-controlled circuit

Photomultiplication-type polymer photodetectors(PM-PPDs)were achieved with polymer P3HT as donor and PY3Se-1V as acceptor based on structure of ITO/PEDOT:PSS/active layer/Al.The optimal weight ratio of P3HT to PY3Se-1V is about 100:3.Amounts of isolated electron traps are formed with PY3Se-1V surrounded by P3HT due to rather less content of PY3Se-1V in active layers and about 0.94 e V energy offset between the lowest unoccupied molecular orbitals(LUMO)of P3HT and PY3Se-1V.The optimal PM-PPDs exhibit broad spectral response from 350 to 950 nm and external quantum efficiency(EQE)values of68,200%at 360 nm,26,400%at 630 nm and 19,500%at 850 nm under-15 V bias.The working mechanism of PM-PPDs is attributed to the interfacial trap-assisted hole tunneling injection from external circuit.The performance of PM-PPDs can be further improved by incorporating appropriate PMBBDT with high hole mobility as the third component.The EQE values of optimal ternary PM-PPDs are increased to 105,000%at 360 nm,40,000%at 630 nm and 31,800%at 850 nm under-15 V bias,benefiting from the enhanced hole transport in ternary active layers.The optimal ternary PM-PPDs were successfully applied in a light-controlled circuit to turn on or turn off light emitting diode(LED).