Time-Resolved Neutron Reflectometry and Photovoltaic Device Studies on Sequentially Deposited PCDTBT-Fullerene Layers

详细信息    查看全文

• 作者：Andrew J. Clulow ; Chen Tao ; Kwan H. Lee ; Marappan Velusamy ; Jake A. McEwan ; Paul E. Shaw ; Norifumi L. Yamada ; Michael James ; Paul L. Burn ; Ian R. Gentle ; Paul Meredith
• 刊名：Langmuir
• 出版年：2014
• 出版时间：September 30, 2014
• 年：2014
• 卷：30
• 期：38
• 页码：11474-11484
• 全文大小：608K
• ISSN：1520-5827

文摘

We have used steady-state and time-resolved neutron reflectometry to study the diffusion of fullerene derivatives into the narrow optical gap polymer poly[N-9鈥?hepta-decanyl-2,7-carbazole-alt-5,5-(4鈥?7鈥?di-2-thienyl-2鈥?1鈥?3鈥?benzothiadiazole)] (PCDTBT) to explore the sequential processing of the donor and acceptor for the preparation of efficient organic solar cells. It was found that when [6,6]-phenyl-C₆₁-butyric-acid-methyl-ester (60-PCBM) was deposited onto a thin film of PCDTBT from dichloromethane (DCM), a three-layer structure was formed that was stable below the glass-transition temperature of the polymer. When good solvents for the polymer were used in conjunction with DCM, both 60-PCBM and [6,6]-phenyl-C₇₁-butyric-acid-methyl-ester (70-PCBM) were seen to form films that had a thick fullerene layer containing little polymer and a PCDTBT-rich layer near the interface with the substrate. Devices composed of films prepared by sequential deposition of the polymer and fullerene had efficiencies of up to 5.3%, with those based on 60-PCBM close to optimized bulk heterojunction (BHJ) cells processed in the conventional manner. Sequential deposition of pure components to form the active layer is attractive for large-area device fabrication, and the results demonstrate that this processing method can give efficient solar cells.