A New Tetracyclic Lactam Building Block for Thick, Broad-Bandgap Photovoltaics
Journal article, 2014
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 π-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.
Author
Renee Kroon
University of South Australia
Chalmers, Chemical and Biological Engineering, Polymer Technology
Amaia Diaz de Zerio Mendaza
Chalmers, Chemical and Biological Engineering, Polymer Technology
Scott Himmelberger
Chalmers, Applied Physics
J. Bergqvist
Stanford University
Olof Bäcke
Chalmers, Applied Physics, Eva Olsson Group
Gregório Couto Faria
Stanford University
University of Sao Paulo (USP)
Feng Gao
Linköping University
Abdulmalik Obaid
Wake Forest University
Wenliu Zhuang
Chalmers, Chemical and Biological Engineering, Polymer Technology
Desta Antenehe Gedefaw
Chalmers, Chemical and Biological Engineering, Polymer Technology
Eva Olsson
Chalmers, Applied Physics, Eva Olsson Group
Olle Inganäs
Linköping University
Alberto Salleo
Stanford University
Christian Müller
Chalmers, Chemical and Biological Engineering, Polymer Technology
Mats Andersson
Chalmers, Chemical and Biological Engineering, Polymer Technology
Journal of the American Chemical Society
0002-7863 (ISSN) 1520-5126 (eISSN)
Vol. 136 33 11578-11581Subject Categories
Polymer Chemistry
Areas of Advance
Nanoscience and Nanotechnology
Energy
Materials Science
DOI
10.1021/ja5051692