Chlorine doped graphene quantum dots: Preparation, properties, and photovoltaic detectors

• Published in: Applied physics letters Vol. 105; no. 11
• Main Authors: Zhao, Jianhong, Tang, Libin, Xiang, Jinzhong, Ji, Rongbin, Yuan, Jun, Zhao, Jun, Yu, Ruiyun, Tai, Yunjian, Song, Liyuan
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 15.09.2014
• Subjects: ANNEALING; Applied physics; CARBON FIBERS; Chlorine; CHLORINE ADDITIONS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Cotton; CURRENTS; Dark current; Degreasing; DETECTION; Detectors; DOPED MATERIALS; Doping; ELECTRIC POTENTIAL; ELECTRICAL PROPERTIES; ELECTRONS; GRAPHENE; LASER RADIATION; Optical properties; Optoelectronic devices; Organic chemistry; Photoelectric effect; Photoelectric emission; PHOTOVOLTAIC EFFECT; Quantum confinement; QUANTUM DOTS; RED SHIFT; TEMPERATURE RANGE 0273-0400 K; VISIBLE RADIATION
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4896278

Graphene quantum dots (GQDs) are becoming one of the hottest advanced functional materials because of the opening of the bandgap due to quantum confinement effect, which shows unique optical and electrical properties. The chlorine doped GQDs (Cl-GQDs) have been fabricated by chemical exfoliation of HCl treated carbon fibers (CFs), which were prepared from degreasing cotton through an annealing process at 1000 °C for 30 min. Raman study shows that both G and 2D peaks of GQDs may be redshifted (softened) by chlorine doping, leading to an n-type doping. The first vertical (Cl)-GQDs based photovoltaic detectors have been demonstrated, both the light absorbing and electron-accepting roles for (Cl)-GQDs in photodetection have been found, resulting in an exceptionally big ratio of photocurrent to dark current as high as ∼105 at room temperature using a 405 nm laser irradiation under the reverse bias voltage. The study expands the application of (Cl)-GQDs to the important optoelectronic detection devices.