Donor/Acceptor Molecular Orientation-Dependent Photovoltaic Performance in All-Polymer Solar Cells

详细信息    查看全文

• 作者：Ke Zhou ; Rui Zhang ; Jiangang Liu ; Mingguang Li ; Xinhong Yu ; Rubo Xing ; Yanchun Han
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：November 18, 2015
• 年：2015
• 卷：7
• 期：45
• 页码：25352-25361
• 全文大小：629K
• ISSN：1944-8252

文摘

The correlated donor/acceptor (D/A) molecular orientation plays a crucial role in solution-processed all-polymer solar cells in term of photovoltaic performance. For the conjugated polymers PTB7-th and P(NDI2OD-T2), the preferential molecular orientation of neat PTB7-th films kept face-on regardless of the properties of processing solvents. However, an increasing content of face-on molecular orientation in the neat P(NDI2OD-T2) films could be found by changing processing solvents from chloronaphthalene (CN) and o-dichlorobenzene (oDCB) to chlorobenzene (CB). Besides, the neat P(NDI2OD-T2) films also exhibited a transformation of preferential molecular orientation from face-on to edge-on when extending film drying time by casting in the same solution. Consequently, a distribution diagram of molecular orientation for P(NDI2OD-T2) films was depicted and the same trend could be observed for the PTB7-th/P(NDI2OD-T2) blend films. By manufacture of photovoltaic devices with blend films, the relationship between the correlated D/A molecular orientation and device performance was established. The short-circuit current (J_sc) of devices processed by CN, oDCB, and CB enhanced gradually from 1.24 to 8.86 mA/cm² with the correlated D/A molecular orientation changing from face-on/edge-on to face-on/face-on, which could be attributed to facile exciton dissociation at D/A interface with the same molecular orientation. Therefore, the power conversion efficiency (PCE) of devices processed by CN, oDCB, and CB improved from 0.53% to 3.52% ultimately.