Rectification behavior in single molecules is a desired device function in molecular electronics and a description of the structural parameters that induce rectification is required for their proper design. To this end, we report a theoretical study using DFT-NEGF method to characterize the level of rectification induced due to conformational features and chemical modifications. We use as model systems molecules consisting of three aromatic rings connected by acetylene linkages. Our results indicate that the degree of rectification increases when donating and withdrawing groups are attached at the beginning and at the end of the transport direction, respectively. Additionally, aromatic rings rotated by 60° enhance rectification. By incorporating these factors into the optimized structure of two new systems, rectification ratios up to 20.08 at 0.3 V were computationally obtained. These systems represent promising molecular rectifiers that could be integrated into photovoltaic devices, where directionality is crucial to increase the efficiency of electron injection and charge transport.

Molecular rectification enhancement based on conformational and chemical modifications: Smart design of molecular devices

254th National Meeting (2017)

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