TY - JOUR
T1 - Tuning Electronic and Morphological Properties for High-Performance Wavelength-Selective Organic Near-Infrared Cavity Photodetectors
AU - Vanderspikken, Jochen
AU - Liu, Quan
AU - Liu, Zhen
AU - Vandermeeren, Tom
AU - Cardeynaels, Tom
AU - Gielen, Sam
AU - Van Mele, Bruno
AU - Van den Brande, Niko
AU - Champagne, Benoît
AU - Vandewal, Koen
AU - Maes, Wouter
N1 - Funding Information:
The authors would like to thank Huguette Penxten for CV analysis and Bart Ruttens for the XRD measurements. They also thank the Research Foundation – Flanders (FWO Vlaanderen) for continuing financial support (Project Nos. G0D0118N, G0B2718N, 1S50820N, and 11D2618N), as well as the European Research Council (ERC, Grant Agreement No. 864625). Q.L. acknowledges financial support from the European Union's Horizon 2020 research and innovation program under the Marie‐Curie Grant Agreement No. 88279.
Funding Information:
The authors would like to thank Huguette Penxten for CV analysis and Bart Ruttens for the XRD measurements. They also thank the Research Foundation – Flanders (FWO Vlaanderen) for continuing financial support (Project Nos. G0D0118N, G0B2718N, 1S50820N, and 11D2618N), as well as the European Research Council (ERC, Grant Agreement No. 864625). Q.L. acknowledges financial support from the European Union's Horizon 2020 research and innovation program under the Marie-Curie Grant Agreement No. 88279.
Publisher Copyright:
© 2021 Wiley-VCH GmbH
PY - 2022/2/23
Y1 - 2022/2/23
N2 - Incorporation of compact spectroscopic near-infrared (NIR) light detectors into various wearable and handheld devices opens up new applications, such as on-the-spot medical diagnostics. To extend beyond the detection window of silicon, i.e., past 1000 nm, organic semiconductors are highly attractive because of their tunable absorption. In particular, organic NIR wavelength-selective detectors have been realized by incorporating donor:acceptor thin films, exhibiting weak intermolecular charge-transfer (CT) absorption, into an optical microcavity architecture. In this work, the alkyl side chains of the well-known PBTTT donor polymer are replaced by alkoxy substituents, hereby redshifting the CT absorption of the polymer:PC61BM blend. It is shown that the unique fullerene intercalation features of the PBTTT polymer are retained when half of the side chains are altered, hereby maximizing the polymer:fullerene interfacial area and thus the CT absorption strength. This is exploited to extend the detection range of organic narrow-band photodetectors with a full-width-at-half-maximum of 30–38 nm to wavelengths between 840 and 1340 nm, yielding detectivities in the range of 5 × 1011 to 1.75 × 1010 Jones, despite the low CT state energy of 0.98 eV. The broad wavelength tuning range achieved using a single polymer:fullerene blend renders this system an ideal candidate for miniature NIR spectrophotometers.
AB - Incorporation of compact spectroscopic near-infrared (NIR) light detectors into various wearable and handheld devices opens up new applications, such as on-the-spot medical diagnostics. To extend beyond the detection window of silicon, i.e., past 1000 nm, organic semiconductors are highly attractive because of their tunable absorption. In particular, organic NIR wavelength-selective detectors have been realized by incorporating donor:acceptor thin films, exhibiting weak intermolecular charge-transfer (CT) absorption, into an optical microcavity architecture. In this work, the alkyl side chains of the well-known PBTTT donor polymer are replaced by alkoxy substituents, hereby redshifting the CT absorption of the polymer:PC61BM blend. It is shown that the unique fullerene intercalation features of the PBTTT polymer are retained when half of the side chains are altered, hereby maximizing the polymer:fullerene interfacial area and thus the CT absorption strength. This is exploited to extend the detection range of organic narrow-band photodetectors with a full-width-at-half-maximum of 30–38 nm to wavelengths between 840 and 1340 nm, yielding detectivities in the range of 5 × 1011 to 1.75 × 1010 Jones, despite the low CT state energy of 0.98 eV. The broad wavelength tuning range achieved using a single polymer:fullerene blend renders this system an ideal candidate for miniature NIR spectrophotometers.
KW - charge-transfer absorption
KW - intercalation
KW - narrow-band
KW - near-infrared
KW - optical cavities
UR - http://www.scopus.com/inward/record.url?scp=85119291314&partnerID=8YFLogxK
U2 - 10.1002/adfm.202108146
DO - 10.1002/adfm.202108146
M3 - Article
AN - SCOPUS:85119291314
SN - 1616-301X
VL - 32
JO - Advanced functional materials
JF - Advanced functional materials
IS - 9
M1 - 2108146
ER -