Sequentially Deposited Active Layer with Bulk-Heterojunction-like Morphology for Efficient Conventional and Inverted All-Polymer Solar Cells

A sequentially deposited (SD) active layer with bulk-heterojunction (BHJ) like morphology is developed by utilizing a naphthalenediimide-based polymer acceptor PTzNDI-T with a strong interchain interaction and low solubility and a well-soluble polymer donor J52-Cl. The SD active layer is prepared by first depositing PTzNDI-T solution and then depositing J52-Cl solution without any post-treatments, and a traditional blend-cast (BC) active layer is cast from the blend solution of J52-Cl:PTzNDI-T. Both the conventional and inverted all-polymer solar cells (all-PSCs) with the BC active layer present nearly no photovoltaic performance. In contrast, based on the SD active layer, not only do the inverted all-PSCs show a dramatically increased PCE of 6.08% but the conventional all-PSCs with the same deposition sequence also exhibit a similarly high PCE of 6.29%. Notably, the SD active layer shows BHJ-like morphology with well-distributed donor and acceptor phases and thus offers a similarly high photovoltaic performance in conventional and inverted all-PSCs with the same deposition sequence of polymer acceptor and donor, which is the first report of SD all-PSCs. These results provide different insight to the SD active layer for high-performance all-PSCs.