Plasmon-Resonant Enhancement of Photocatalysis on Monolayer WSe2

• DOI: 10.1021/acsphotonics.9b00089
• Publication Date: 2019-02-19T13:55:40Z
• Authors: Jihan Chen; Connor S. Bailey; Yilun Hong; Li Wang; Zhi Cai; Lang Shen; Bingya Hou; Yu Wang; Haotian Shi; Justin Sambur; Wencai Ren; Eric Pop; Stephen B. Cronin
• Keywords: Tungsten diselenide; Photocurrent; Nanochemistry; Photoelectrochemistry; Visible spectrum

We report plasmonic enhancement of photocatalysis by depositing 5 nm Au nanoislands onto tungsten diselenide (WSe2) monolayer films. Under 532 wavelength illumination, the bare WSe2 film produces a relatively small photocurrent (20 nA). With addition nanoparticles, we observe enhancements up to 7× (0.14 μA) in measured photocurrent. Despite these photocurrents, it is remarkable that adequate charge separating fields are generated over just 7.3 Å material. Here, improvement photocatalytic performance caused local electric field produced nanoislands, as verified electromagnetic simulations using finite different time domain (FDTD) method. The near-field optical increases electron–hole pair generation rate at surface WSe2, thus, increasing amount photogenerated contributing photoelectrochemical reactions. reducing effective area contact with electrolytic solution 70%, couple incident light very effectively from far near plane thereby improving overall photoconversion efficiency 3.5% 24.7%.