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Photoresponse of polyaniline-functionalized graphene quantum dots / Sin Ki Lai; Chi Man Luk; Libin Tang; Kar Seng Teng; Shu Ping Lau

Nanoscale, Volume: 7, Issue: 12, Pages: 5338 - 5343

Swansea University Author: Teng, Vincent

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DOI (Published version): 10.1039/c4nr07565j

Abstract

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...

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Published in: Nanoscale
ISSN: 2040-3364 2040-3372
Published: 2015
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URI: https://cronfa.swan.ac.uk/Record/cronfa21240
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Abstract: 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 (I–V) 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.
College: College of Engineering
Issue: 12
Start Page: 5338
End Page: 5343