Fig. 3: Reactant and product structure of pre-oxidized (protected) chGNRs.
From: Circumventing the stability problems of graphene nanoribbon zigzag edges
a, Structures of the two k-DBBA precursor isomers. b, Overview STM image of self-assembled islands of ketone chiral nanoribbons after annealing the precursors in steps up to 430 °C. Scanning parameters are I = 30 pA, U = −0.5 V. c, Chemical structure of the k-chGNRs, with Clar sextets marked by a grey background. The increase from two to four Clar sextets when comparing pristine GNRs and these pre-oxidized GNRs supports the greater stability of the latter. d, BR-STM image of a ketone chiral nanoribbon after air exposure and post-annealing to 200 °C in ultra-high vacuum conditions. The sharp features at the edge of each central ring correspond to the ketone groups. No changes are observed before and after the air exposure (CO tip, constant height, U = 8 mV), showing the air-stable character of the nanoribbons.
