Rigid, Conjugated Macrocycles for High Performance Organic Photodetectors

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• 作者：Boyuan Zhang ; M. Tuan Trinh ; Brandon Fowler ; Melissa Ball ; Qizhi Xu ; Fay Ng ; Michael L. Steigerwald ; X.-Y. ZhuColin Nuckolls ; Yu Zhong
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：December 21, 2016
• 年：2016
• 卷：138
• 期：50
• 页码：16426-16431
• 全文大小：448K
• ISSN：1520-5126

文摘

Organic photodetectors (OPDs) are attractive for their high optical absorption coefficient, broad wavelength tunability, and compatibility with lightweight and flexible devices. Here we describe a new molecular design that enables high performance organic photodetectors. We use a rigid, conjugated macrocycle as the electron acceptor in devices to obtain high photocurrent and low dark current. We make a direct comparison between the devices made with the macrocyclic acceptor and an acyclic control molecule; we find that the superior performance of the macrocycle originates from its rigid, conjugated, and cyclic structure. The macrocycle’s rigid structure reduces the number of charged defects originating from deformed sp² carbons and covalent defects from photo/thermoactivation. With this molecular design, we are able to suppress dark current density while retaining high responsivity in an ultrasensitive nonfullerene OPD. Importantly, we achieve a detectivity of ∼10¹⁴ Jones at near zero bias voltage. This is without the need for extra carrier blocking layers commonly employed in fullerene-based devices. Our devices are comparable to the best fullerene-based photodetectors, and the sensitivity at low working voltages (<0.1 V) is a record for nonfullerene OPDs.