Anomalous behaviors of visible luminescence from graphene quantum dots: Interplay between size and shape

Sung Kim, Sung Won Hwang, Min Kook Kim, Dong Yeol Shin, Dong Hee Shin, Chang Oh Kim, Seung Bum Yang, Jae Hee Park, Euyheon Hwang, Suk Ho Choi, Geunwoo Ko, Sunghyun Sim, Cheolsoo Sone, Hyoung Joon Choi, Sukang Bae, Byung Hee Hong

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Abstract

For the application of graphene quantum dots (GQDs) to optoelectronic nanodevices, it is of critical importance to understand the mechanisms which result in novel phenomena of their light absorption/emission. Here, we present size-dependent shape/edge-state variations of GQDs and visible photoluminescence (PL) showing anomalous size dependences. With varying the average size (d a) of GQDs from 5 to 35 nm, the peak energy of the absorption spectra monotonically decreases, while that of the visible PL spectra unusually shows nonmonotonic behaviors having a minimum at d a = ∼17 nm. The PL behaviors can be attributed to the novel feature of GQDs, that is, the circular-to-polygonal-shape and corresponding edge-state variations of GQDs at d a = ∼17 nm as the GQD size increases, as demonstrated by high-resolution transmission electron microscopy.

Original languageEnglish
Pages (from-to)8203-8208
Number of pages6
JournalACS Nano
Volume6
Issue number9
DOIs
Publication statusPublished - 2012 Sep 25

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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    Kim, S., Hwang, S. W., Kim, M. K., Shin, D. Y., Shin, D. H., Kim, C. O., Yang, S. B., Park, J. H., Hwang, E., Choi, S. H., Ko, G., Sim, S., Sone, C., Choi, H. J., Bae, S., & Hong, B. H. (2012). Anomalous behaviors of visible luminescence from graphene quantum dots: Interplay between size and shape. ACS Nano, 6(9), 8203-8208. https://doi.org/10.1021/nn302878r