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

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• 作者：Renee Kroon ; Amaia Diaz de Zerio Mendaza ; Scott Himmelberger ; Jonas Bergqvist ; Olof B盲cke ; Greg贸rio Couto Faria ; Feng Gao ; Abdulmalik Obaid ; Wenliu Zhuang ; Desta Gedefaw ; Eva Olsson ; Olle Ingan盲s ; Alberto Salleo ; Christian M眉ller ; Mats R. Andersson
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：August 20, 2014
• 年：2014
• 卷：136
• 期：33
• 页码：11578-11581
• 全文大小：270K
• ISSN：1520-5126

文摘

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 蟺-stacking of the polymer backbone, which was retained in PTNT:fullerene 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 5% 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 400 nm 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.