Fig. 6: STM analysis of GNRs along the various steps in the synthesis process of its pre-oxidized (protected) form, hydrogenation and annealing (deprotection).
From: Circumventing the stability problems of graphene nanoribbon zigzag edges
a, Overview STM image (I = 100 pA, U = −0.1 V) of mostly metal-coordinated ketone GNRs after their synthesis on Au(111). b, Overview STM image (I = 50 pA, U = −1.0 V) of the same GNR sample after exposure to atomic hydrogen. c, STM image (I = 50 pA, U = −0.5 V) of the same sample after annealing to 330 °C. The GNRs mostly consist of pristine sections, with some remaining ketone defects, proving a successful deprotection of the air-stable k-chGNRs. d,e, BR-STM (constant height, CO tip, U = 5 mV; d) and STM (I = 100 pA, U = −0.5 V; e) of one of the GNRs from the post-annealed sample (scale bars, 500 pm). Two neighbouring metal-coordinated ketone defects are observed on the two sections at the lower end of the ribbon. f, nc-AFM image of as-grown k-chGNRs. g, nc-AFM image of lightly hydrogenated k-chGNRs, showing very inhomogeneous hydrogenation motifs. h, Detail of lightly hydrogenated k-chGNRs. i, The proposed chemical structure of the detail in panel h, which includes various types of products along with deoxidized units.
