Enhanced photoelectric performance of GQDs anchored WO3 with a ‘dot-on-nanoparticle’ structure

Abstract

WO _3 /GQDs-H composites were synthesized by a hydrothermal method using WCl _6 as the tungsten source. Various analyses were conducted to investigate the composition, structure, morphology and performance of the composites. WO _3 /GQDs-H composites formed a special ‘dot-on-nanoparticle’ structure by anchoring GQDs on the surface of WO _3 . The lattice spacings of 0.34 and 0.386 nm were attributed to the (002) facets of GQDs and WO _3 , respectively. Compared to blank WO _3 , an obvious shift to higher value in the binding energy of W ^6+ and W ^5+ and a decreased I _D /I _G value in the Raman spectra could be observed for WO _3 /GQDs-H composites. The photocurrent value of hydrothermal synthesized WO _3 /GQDs-H composites achieved 1.56 × 10 ^–5 A cm ^−2 , which was obviously prior to that of blank WO _3 and mechanically mixed WO _3 /GQDs. The result indicated that the hydrothermal process promoted GQDs as a conductive route to transfer photoexcited electrons and improve the photoelectric performance of WO _3 /GQDs in comparison to the mechanical mixture process.

Keywords

• WO3/GQDs
• hydrothermal method
• ‘dot-on-nanoparticle’ structure
• photoelectric performance