Photoconductivity of a single small-molecule organic nanowire

The photoconductivity of small-molecule organic single-crystal methyl-squarylium (MeSq) nanowires was analyzed that showed high light sensitivity with I_light/I_dark ratios on the order of 10³, good response speed, excellent stability, and reproducibility. It was found that this type of molecule can easily aggregate and grow into one-dimensional (1D) nanostructures in a slipped stack arrangement directed by the strong intermolecular interactions between the acceptor (A) and the donor (D) groups under appropriate conditions. It was also found that MeSq nanowires offered high sensitivity to light, and increase in conductance and a simple power-law dependence on light intensity. The results show that the strong absorption of visible light of MeSq nanowires can be highly beneficial for applications in high-efficiency organic photovoltaic devices such as photodetectors, sensors, and flexible electronics.