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Issue 12, 2015
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Photoresponse of polyaniline-functionalized graphene quantum dots

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Polyaniline-functionalized graphene quantum dots (PANI-GQD) and pristine graphene quantum dots (GQDs) were utilized for optoelectronic devices. The PANI-GQD based photodetector exhibited higher responsivity which is about an order of magnitude at 405 nm and 7 folds at 532 nm as compared to GQD-based photodetectors. The improved photoresponse is attributed to the enhanced interconnection of GQD by island-like polymer matrices, which facilitate carrier transport within the polymer matrices. The optically tunable current–voltage (IV) hysteresis of PANI-GQD was also demonstrated. The hysteresis magnifies progressively with light intensity at a scan range of ±1 V. Both GQD and PANI-GQD devices change from positive to negative photocurrent when the bias reaches 4 V. Photogenerated carriers are excited to the trapping states in GQDs with increased bias. The trapped charges interact with charges injected from the electrodes which results in a net decrease of free charge carriers and a negative photocurrent. The photocurrent switching phenomenon in GQD and PANI-GQD devices may open up novel applications in optoelectronics.

Graphical abstract: Photoresponse of polyaniline-functionalized graphene quantum dots

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Supplementary files

Article information

23 Dec 2014
14 Feb 2015
First published
16 Feb 2015

Nanoscale, 2015,7, 5338-5343
Article type
Author version available

Photoresponse of polyaniline-functionalized graphene quantum dots

S. K. Lai, C. M. Luk, L. Tang, K. S. Teng and S. P. Lau, Nanoscale, 2015, 7, 5338
DOI: 10.1039/C4NR07565J

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