Fluorographene: A Wide Bandgap Semiconductor with Ultraviolet Luminescence

Abstract

The manipulation of the bandgap of graphene by various means has stirred great interest for potential applications. Here we show that treatment of graphene with xenon difluoride produces a partially fluorinated graphene (fluorographene) with covalent C-F bonding and local sp(3)-carbon hybridization. The material was characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, electron energy loss spectroscopy, photoluminescence spectroscopy, and near edge X-ray absorption spectroscopy. These results confirm the structural features of the fluorographane with a bandgap of 3.8 eV, close to that calculated for fluorinated single layer graphene, (CF)(n). The material luminesces broadly in the UV and visible light regions, and has optical properties resembling diamond, with both excitonic and direct optical absorption and emission features. These results suggest the use of fluorographane as a new, readily prepared material for electronic, optoelectronic applications, and energy harvesting applications.

Band gaps and structural properties of graphene halides and their derivates: A hybrid functional study with localized orbital basis sets

“…6,28 Photoluminescence measurements have identified an emission peak at 3.80 eV in the fluorographene dispersion spectrum in acetone, which has been assigned to band-to-band recombination of a free electron and hole. 27 Theoretical calculations of the fluorographene band gap by GGA DFT have suggested values around 3.1 eV, 7,15,16,22,25 similar to values for graphite fluoride. 23,24 The agreement between theoretical and experimental band-gap values is probably accidental because high-level theoretical calculations using GW predict the band gap to be around 7.5 eV.…”

Monolithic graphene oxide sheets with controllable composition

“…1j, inset), suggesting the presence of foreign species in the graphene framework 28,29 . Furthermore, atomic force microscopy (AFM) measurements show that the surface root-mean-square roughness of the graphene frameworks that were transferred onto SiO 2 /Si(100) was 2-3 times larger than that of the pristine graphene on SiO 2 / Si(100), which could be attributed to the random covalent attachment of foreign species onto the surface of the graphene framework 30 .…”

Janus graphene from asymmetric two-dimensional chemistry

“…Physisorption of chemical species on graphene would provide a facile way to alter its electronic properties 12 , however, covalent chemical modification shows a great advantage in achieving permanent stabilisation for long-term usage 13 . Previous attempts towards fundamental research on covalent functionalisation of graphene mainly involved the development of new modification strategies (for example, hydrogenation [14][15][16][17] , fluorination [18][19][20] , chlorination 21,22 , diazotization [23][24][25][26][27] and other cycloaddition reactions [28][29][30][31] ), covalent addition of edge and defects 27,32 , fabrication of chemical superlattices 26,33 and quantum effects in graphene modification 17,34 . Of the various significant research activities on graphene chemistry that have been conducted, nearly no work to date has been focused on the asymmetric chemistry of this ideal 2D atomic crystal via covalently attaching different functional groups on its two faces simultaneously.…”