10.1021/acsami.7b00510.s001 Qianqian Sun Qianqian Sun Fujun Zhang Fujun Zhang Qiaoshi An Qiaoshi An Miao Zhang Miao Zhang Xiaoling Ma Xiaoling Ma Jian Zhang Jian Zhang Simultaneously Enhanced Efficiency and Stability of Polymer Solar Cells by Employing Solvent Additive and Upside-down Drying Method American Chemical Society 2017 PTB 7-Th 71 BM stability PC 71 BM molecules power conversion efficiency glass Petri dish PCE Polymer Solar Cells method PSC Employing Solvent Additive upside-down Upside-down Drying Method phase separation PBDT-TS transmission electron microscopy incidence X-ray diffraction polymer PffBT 4T 71 BM X-ray photoelectron spectroscopy 2017-02-23 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Simultaneously_Enhanced_Efficiency_and_Stability_of_Polymer_Solar_Cells_by_Employing_Solvent_Additive_and_Upside-down_Drying_Method/4718929 The morphology of active layer plays an important role in determining the power conversion efficiency (PCE) and stability of polymer solar cells (PSCs), which strongly depend on the dynamic drying process of active layer. In this work, an efficient and universal method was developed to let active layer undergo upside-down drying process in a covered glass Petri dish. For the PSCs based on PTB7-Th:PC<sub>71</sub>BM, the champion PCEs were improved from 8.58% to 9.64% by mixing 3 vol % 1,8-di-iodooctane and further to 10.30% by employing upside-down drying method. The enhanced PCEs of PSCs with active layers undergoing upside-down drying process are mainly attributed to the optimized vertical phase separation, the more ordered and tightly packed π–π stacking of polymer molecules. Meanwhile, PC<sub>71</sub>BM molecules can be frozen in more ordered and tightly packed π–π stacking polymer network, which lead to the enhanced stability of PSCs. The universality of upside-down drying method can be solidly confirmed from PSCs with PTB7:PC<sub>71</sub>BM, PffBT4T-2OD:PC<sub>71</sub>BM, or PBDT-TS1:PC<sub>71</sub>BM as active layers, respectively. The molecular packing and phase separation of blend films with different solvent additives and drying methods were investigated by grazing incidence X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy.