Manipulating the Charge Transfer Absorption for Narrowband Light Detection in the Near-Infrared

Christina Kaiser, Karl Sebastian Schellhammer, Johannes Benduhn, Bernhard Siegmund, Manuel Tropiano, Jonas Kublitski, Donato Spoltore, Michel Panhans, Olaf Zeika, Frank Ortmann, Paul Meredith, Ardalan Armin, Koen Vandewal

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Charge generation and recombination processes at interfaces between electron donating (donor, D) and accepting molecules (acceptor, A) are mediated by intermolecular charge-transfer (CT) states. Since organic photovoltaic and photodetecting devices rely on D-A interfaces, an understanding of the molecular and morphological aspects governing CT state properties is crucial. In this paper, we synthesize a novel series of bi(thio)pyranylidene donor molecules and show how the interplay of molecular structure and energy levels in a D-C60 blend affect the line shape of the CT absorption cross section. By rationally designing the molecule 2,2′,6,6′-tetra-(2-methylthienyl)-4,4′-bithiopyranylidene, we achieve a 2 times stronger CT absorption peak than the literature-known molecule 2,2′,6,6′-tetraphenyl-4,4′-bipyranylidene when blended with C60. The low CT state energy combined with relatively strong CT absorption of this new material blend is exploited by fabricating near-infrared, cavity enhanced narrowband detectors. The photodetectors cover an impressive wavelength range from 810 to 1665 nm with line widths between 30 and 50 nm.

Original languageEnglish
Pages (from-to)9325-9330
Number of pages6
JournalChemistry of Materials
Issue number22
StatePublished - 26 Nov 2019
Externally publishedYes


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