Ultra-Narrowband Near-Infrared Responsive J-Aggregates of Fused Quinoidal Tetracyanoindacenodithiophene.

Narrowband photoresponsive molecules are highly coveted in high-resolution imaging, sensing and monochromatic photodetection, especially those extending into the near-infrared (NIR) spectral range. Here we report a new class of J-aggregating materials based on quinoidal indacenodithiophenes (IDT) which exhibit an ultra-narrowband (full width half maxima of 22 nm) NIR absorption peak centered at 770 nm. The spectral width is readily tuned by the length of the solubilising alkyl group, with longer chains resulting in significant spectral narrowing. The J-aggregate behaviour is confirmed by a combination of excited state lifetime measurements and single-crystal X-ray diffraction measurements. Their utility as electron transporting materials is demonstrated in both transistor and phototransistor devices, with the latter demonstrating good response at NIR wavelengths (780 nm) over a range of intensities. This article is protected by copyright. All rights reserved.