Ultranarrow Bandwidth Organic Photodiodes by Exchange Narrowing in Merocyanine H‐ and J‐Aggregate Excitonic Systems. (21st September 2018)

• Record Type: Journal Article
• Authors: Liess, Andreas; Arjona‐Esteban, Alhama; Kudzus, Astrid; Albert, Julius; Krause, Ana‐Maria; Lv, Aifeng; Stolte, Matthias; Meerholz, Klaus; Würthner, Frank
• Is Part Of: Advanced functional materials. Volume 29:Number 21(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-09-21
• Subjects: dye aggregates -- exciton coupling -- merocyanine dyes/pigments -- narrow bandwidth -- organic photodiodes; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201805058
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Ultranarrowband organic photodiodes (OPDs) are demonstrated for thin film solid state materials composed of tightly packed dipolar merocyanine dyes. For these dyes the packing arrangement can be controlled by the bulkiness of the donor substituent, leading to either strong H‐ or strong J‐type exciton coupling in the interesting blue (H‐aggregate) and NIR (J‐aggregate) spectral ranges. Both bands are shown to arise from one single exciton band according to fluorescence measurements and are not just a mere consequence of different polymorphs within the same thin film. By fabrication of organic thin‐film transistors, these dyes are demonstrated to exhibit hole transport behavior in spin‐coated thin films. Moreover, when used as organic photodiodes in planar heterojunctions with C60 fullerene, they show wavelength‐selective photocurrents in the solid state with maximum external quantum efficiencies of up to 11% and ultranarrow bandwidths down to 30 nm. Thereby, narrowing the linewidths of optoelectronic functional materials by exciton coupling provides a powerful approach to produce ultranarrowband organic photodiodes. Abstract : Organic photodiodes composed of merocyanine dye H‐ and J‐aggregates are fabricated. The dye aggregates' absorption band can be tuned by the donor‐substituent‐dependent packing of the dyes to give ultranarrow bandwidths down to 30 nm and maximum external quantum efficiencies of up to 11% for the H‐band and 9% for the J‐band.