Low-LUMO acceptor polymers for high-gain all-polymer photodiodes

In this work, we report three acceptor polymers with low levels of lowest unoccupied molecular orbital (LUMO) energies and studies on all-polymer photodiodes. By employing these polymers as electron acceptors and PTB7-Th as electron donors, we prepared all-polymer photodiodes that exhibited a high gain in external quantum efficiency (EQE) and high detectivity. In particular, P3-based devices showed EQE over 40 000%, responsivity over 110 A W−1 and a specific detectivity of 3.5 × 1014 Jones, representing the best result of all-polymer photodiodes reported to date. Our work has demonstrated that high gain all-polymer photodiodes could be readily achieved by using appropriate interlayers and low-LUMO acceptor polymers.