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Research Highlight

Engineering Edge States of Graphene Nanoribbons for Narrow-Band Photoluminescence

Engineering Edge States of Graphene Nanoribbons for Narrow-Band Photoluminescence
a: Sketch of photogenerated excitons in the GNR traveling ballistically to the junction of GNR-GND and recombining to emit photons with an energy of h’ defined by the quantum-well-like sates at the junction. b: STM image of a GNR-GND junction fused covalently to the GNR edge.
c: Ultra-narrow PL from the GNR-GND junction with a peak energy of 2.07 eV and linewidth of 3 meV at 4 K.

Scientific Achievement

A bottom-up approach for coupling graphene nanodots (GND) covalently at the edges of graphene nanoribbons (GNR) to create quantum-well-like states for well-defined narrow-band light emission.

Significance and Impact

This work establishes a new strategy to achieve narrow-band emission by engineering interface states of mixed-dimensional GNR-GND heterojunctions with atomic precision.

Research Details

– Covalent heterostructures are formed by fusing GNDs to the edges of GNRs via controlled on-surface reactions of molecular precursors. – Scanning tunneling microscopy (STM) reveals the quantum-well-like electronic states and photoluminescence (PL) spectra show a defined optical transition energy with an ultra-narrow linewidth.   C. Ma, Z. Xiao, A. A. Puretzky, H. Wang, A. Mohsin, J. Huang, L. Liang, Y. Luo, B. J. Lawrie, G. Gu, W. Lu, K. Hong, J. Bernholc, and A.-P. Li, "Engineering Edge States of Graphene Nanoribbons for Narrow-Band Photoluminescence," ACS Nano 14, 5090-5098 (2020). DOI: 10.1021/acsnano.0c01737