M. Rinaldi, Günther Rupprechter, Zhijing Feng, G. Pastore, Alberto Ferrari, Erik Vesselli, Roberto Costantini, Giovanni Comelli, Christoph Rameshan, Matteo Roiaz, Manuel Corva, Martina Dell'Angela, Nicola Seriani, Corva, M., Ferrari, A., Rinaldi, M., Feng, Z., Roiaz, M., Rameshan, C., Rupprechter, G., Costantini, R., Dell’Angela, M., Pastore, G., Comelli, G., Seriani, N., and Vesselli, E.
Long-lived excitons formed upon visible light absorption play an essential role in photovoltaics, photocatalysis, and even in high-density information storage. Here, we describe a self-assembled two-dimensional metal-organic crystal, composed of graphene-supported macrocycles, each hosting a single FeN4 center, where a single carbon monoxide molecule can adsorb. In this heme-like biomimetic model system, excitons are generated by visible laser light upon a spin transition associated with the layer 2D crystallinity, and are simultaneously detected via the carbon monoxide ligand stretching mode at room temperature and near-ambient pressure. The proposed mechanism is supported by the results of infrared and time-resolved pump-probe spectroscopies, and by ab initio theoretical methods, opening a path towards the handling of exciton dynamics on 2D biomimetic crystals., Long-lived excitons in a two-dimensional metal-organic crystal can be produced by visible light and detected by infrared radiation. Here, the authors show that the excitonic state of a biomimetic macrocycle can be ‘read’ by measuring the vibrations of an adsorbed ligand.