Excited states engineering enables efficient near-infrared lasing in nanographenes
Giuseppe M. Paternò, Qiang Chen, Rafael Muñoz‐Mármol, Michele Guizzardi, Víctor Bonal, Ryota Kabe, Alexander Barker, Pedro G. Boj, Shreyam Chatterjee, Yutaka Ie, José M. Villalvilla, José A. Quintana, Francesco Scotognella, Kläus Müllen, María A. Díaz‐García, Akimitsu Narita, Guglielmo Lanzani
Abstract
, respectively). Photophysical results indicate that, besides the minimisation of ground state absorption losses, such substitution permits to suppress the detrimental excited state absorption in the NIR, which likely arises from a dark state with charge-transfer character and triplets. This has enabled NIR lasing (720 nm) from all-solution processed distributed feedback devices with one order of magnitude lower thresholds than those of previously reported NIR-emitting NGs. This study represents an advance in the field of NGs and, in general, organic semiconductor photonics, towards the development of cheap and stable NIR lasers.