| Abstrakt: |
In this work, planar-heterojunction organic phototransistors (OPT) have been constructed from solution process, by combining a semiconducting diketopyrrolopyrrole polymer PDVT-10 and a novel carbon nano-material-carbon quantum dots (CQDs). The PDVT-10/CQDs planar heterojunction films, possessing the optical properties of both PDVT-10 and CQDs, reveal strong optical absorption in a wide spectral region from ultraviolet to near infra-red. Compared with pristine PDVT-10 phototransistors, such planar-heterojunction OPTs exhibit a remarkably higher performance on broad-spectrum photo-detection, with a photoresponsivity of 2.6 x 104 A/W, a specific detectivity of 2.4 x 1013 Jones, and maximum light sensitivity higher than 104 under the 450-nm laser irradiation, as well as with a responsivity of 4.4x104 A/W and a specific detectivity of 1.2 x1013 Jones under the 808-nm laser irradiation. Based on the study of the photo-response mechanism for these devices, the performance improvement of the PDVT-10/CQDs based OPTs should be attributed to the favorable energy level alignment at the PDVT-10/CQDs interfaces, which enhances interfacial exciton dissociation and charge separation, meanwhile effectively suppresses the hole-electron recombination in the light-absorption layer. Furthermore, the formation of efficient carrier conduction pathway is benefited from high hole-mobility of PDVT-10 for the OPT performance enhancement. Our work offers a valuable avenue for the development of high performance light detectors. [ABSTRACT FROM AUTHOR] |
