Broadband organic color photodetectors with high gain based on C60-doped tri-phase bulk heterojunction

Abstract

We experimentally investigate the spectrum broadening of P3HT:PC61BM:PBDT-TT-F tri-phase bulk heterojunction active layer, and the influence of material mixing degree on the optoelectronic performance of detectors is also discussed. In addition, the mechanism of gain for C60-doped P3HT:PC61BM:PBDT-TT-F detectors is studied. On the basis, we obtain a broadband with responsive spectra from 350 ~ 750 nm and photomultiplication (PM) detector. The resulting detector exhibits responsivity of 2.1, 3.95, 5.05 A/W and the external quantum efficiency of 415%, 924%, and 1361%, respectively, under the illumination of three primary light at − 4 V bias. Moreover, the specific detectivity approaches or exceeds 1012 Jones. The results indicates that the absorption spectrum of active layer can be used to broaden by adding small amount of spectrum broadening material while keeping the original morphology of binary bulk heterojunction. A small weight of C60 dispersed in tri-phase bulk heterojunction active layer can be regarded as electron trap. Combining the advantage of high exciton dissociation efficiency of bulk heterojunction, PM-type organic photodetectors working at low bias can be achieved by triggering hole tunneling injection from cathode.