Tunable Band Alignment with Unperturbed Carrier Mobility of On-Surface Synthesized Organic Semiconducting Wires

Abstract

The tunable properties of molecular materials place them among the favorites for a variety of future generation devices. In addition, to maintain the current trend of miniaturization of those devices, a departure from the present top-down production methods may soon be required and self-assembly appears among the most promising alternatives. On-surface synthesis unites the promises of molecular materials and of self-assembly, with the sturdiness of covalently bonded structures: an ideal scenario for future applications. Following this idea, we report the synthesis of functional extended nanowires by self-assembly. In particular, the products correspond to one-dimensional organic semiconductors. The uniaxial alignment provided by our substrate templates allows us to access with exquisite detail their electronic properties, including the full valence band dispersion, by combining local probes with spatial averaging techniques. We show how, by selectively doping the molecular precursors, the product’s energy level alignment can be tuned without compromising the charge carrier’s mobility.

Bottom-Up Fabrication of Atomically Precise Graphene Nanoribbons

“…(k) Adapted with permission from [48]. (l) Adapted with permission from [36]. (m) Adapted with permission from [49].…”

Functionalized Graphdiyne Nanowires: On‐Surface Synthesis and Assessment of Band Structure, Flexibility, and Information Storage Potential

“…Figure S20, Supporting Information), our analysis reveals that the hole effective mass amounts to between 0.06 and 0.1 m 0 at the top of the HOB. In comparison to 7‐armchair graphene nanoribbons and polyphenylene nanowires, where effective masses between 0.21 and 0.17 m 0 were reported, the 3‐2 GDY nanowire possesses a factor 2 to 3 smaller effective mass. Thus, under the assumption of comparable scattering rates, a significantly higher charge‐carrier mobility should be achievable in f‐GDY nanowires.…”

Switching from Reactant to Substrate Engineering in the Selective Synthesis of Graphene Nanoribbons

“…As the DBTP-decorated surfaces are annealed, the molecules first polymerize into poly-paraphenylene (PPP). 20,27,28,30 At higher temperatures, neighboring PPP chains laterally fuse together and form armchair-oriented graphene nanoribbons (aGNRs). 27,28 Following the same experimental procedures on both surfaces, scanning tunneling microscopy (STM) reveals that a flat Au(111) surface ends up decorated with few remnant PPP wire segments plus a disordered mixture of aGNRs of varying width.…”

“…2c). 20,27,28,40,41 However, the underlying surface appears completely reconstructed, hosting the alternating rows of PPP and Br on much wider and irregular terraces. This reconstruction is associated to the strong interaction of the halogen atoms with the stepped Au substrate, 42 but will not be discussed further as it is beyond the scope of this work.…”