A New Tetracyclic Lactam Building Block for Thick, Broad-Bandgap Photovoltaics

作者：Kroon, Renee^*; Mendaza, Amaia Diaz de Zerio; Himmelberger, Scott; Bergqvist, Jonas; Backe, Olof; Faria, Gregorio Couto; Gao, Feng; Obaid, Abdulmalik; Zhuang, Wenliu; Gedefaw, Desta; Olsson, Eva; Inganas, Olle; Salleo, Alberto; Muller, Christian; Andersson, Mats R.

来源：Journal of the American Chemical Society, 2014, 136(33): 11578-11581.

DOI：10.1021/ja5051692

• SOLAR-CELLS
• HIGHLY EFFICIENT
• POLYMER
• COPOLYMERS
• ABSORPTION

A new tetracyclic lactam building block for polymer semiconductors is reported that was designed to combine the many favorable properties that larger fused and/or amide-containing building blocks can induce, including improved solid-state packing, high charge carrier mobility, and improved charge separation. Copolymerization with thiophene resulted in a semicrystalline conjugated polymer, PTNT, with a broad bandgap of 2.2 eV. Grazing incidence wide-angle X-ray scattering of PTNT thin films revealed a strong tendency for face-on pi-stacking of the polymer backbone, which was retained in PTNT:firllerene blends. Corresponding solar cells featured a high open-circuit voltage of 0.9 V, a fill factor around 0.6, and a power conversion efficiency as high as 596 for >200 nm thick active layers, regardless of variations in blend stoichiometry and nanostructure. Moreover, efficiencies of >4% could be retained when thick active layers of similar to 400 rim were employed. Overall, these values are the highest reported for a conjugated polymer with such a broad bandgap and are unprecedented in materials for tandem and particularly ternary blend photovoltaics. Hence, the newly developed tetracyclic lactam unit has significant potential as a conjugated building block in future organic electronic materials.

• 出版日期2014-8-20