Periodic Reporting for period 5 - e-Sequence (e-Sequence: a sequential approach to engineer heteroatom doped graphene nanoribbons for electronic applications)
Période du rapport: 2023-11-01 au 2024-10-31
Graphene nanoribbons (NR) are quasi-1D nanostructures with discrete band gaps, ballistic conduction, and one-atom thickness. Such properties make them ideal candidates to develop low-dimensional semiconductors, which are essential components in nanoelectronics. Atomically-precise control over the structure of NR (width, length, edge, doping) is crucial to fully exploit their potential. However, current approaches for the synthesis of NR suffer from several drawbacks that do not allow attaining such level of precision, therefore alternative methods need to be sought. e-Sequence has developed an unprecedented approach that assembles stepwise small molecular building blocks into NR to specifically target the most important challenges in NR synthesis. Such approach will enable the preparation of an unlimited number of NR with atomically-precise control over their structure, exceeding the limits of existing methods.
Graphene nanoribbon (GNR) properties are dominated by structural variables, such as edge structure, length, width, and heteroatom-doping, all requiring atomic precision to harness the full application potential of GNRs. Although the length influences key GNR properties, synthetic methods that allow control over the length remain underdeveloped, and the effects of length on GNR properties remain underexplored. We have developed a series of iterative approaches enabling the synthesis of a series of length-controlled, ultralong atomically precise GNRs. The longest GNR displays a 920-atoms core with a 35.8-nm long (147 linearly fused rings) backbone. The unprecedented solubility of these type of monodisperse GNRs enabled their purification by column chromatography and their investigation by a broad range of structural, optoelectronic, and redox characterization techniques. In addition, this GNR length control allowed us to unambiguously establishing correlations between GNR length and properties, particularly electrical conductivity.
We have developed a series of iterative approaches enabling the synthesis of a series of length-controlled, ultralong atomically precise GNRs. The convergent (accelerated) iterative synthesis of NRs developed has provided excellent results beyond our expectations in terms of lengths and solubility. This method has enabled the synthesis of nanoribbons with a 920-atoms core with a 35.8-nm long (147 linearly fused rings) backbone in just three synthetic steps from building blocks of 2 nm in length.