Browsing by Author "Li, Xuanhua"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item An all-copper plasmonic sandwich system obtained through directly depositing copper NPs on a CVD grown graphene/copper film and its application in SERS(Royal Society of Chemistry, 2015-05-11) Li, Xuanhua; Ren, Xingang; Zhang, Yongxing; Choy, Wallace C. H.; Wei, Bingqing; Xuanhua Li, Xingang Ren, Yongxing Zhang, Wallace C. H. Choy and Bingqing Wei; Wei, BingqingA simple, low-cost, all-copper sandwich system has been obtained through directly depositing Cu nanoparticles (NPs) onto a graphene sheet, which has already been grown on a Cu foil (Cu-NGF). The new design inherits two key advantages: (1) the materials of the NGF coupling system are composed of only cheaper Cu instead of Au and Ag, (2) direct fabrication of the system without transferring graphene will greatly lower the fabrication cost. More importantly, the Cu-NFG system shows a high sensitivity in surface-enhanced Raman scattering (SERS) with the highest enhancement factor (EF, over 1.89 × 107) reported to date in Cu plasmonic systems. Experimental and theoretical results reveal that the strong EF is mainly because of the strong near-field coupling between Cu NPs and Cu films at the optimal angle of incidence, opening up a new route for Cu materials in SERS applications.Item Blending poly(2-ethyl-2-oxazoline) with hydrophobic polymers as a hybrid adhesive with enhanced water-resistant properties(Journal of Applied Polymer Science, 2021-07-16) Zhang, Yuanyuan; Li, Xuanhua; Guo, Shaohui; Wei, BingqingThe use of poly(2-ethyl-2-oxazoline) (PEOX) in a wet environment is limited because of its high hydrophilicity. In this study, PEOX based blends were prepared via blending PEOX with hydrophobic polymers, such as poly(styrene-co-acrylonitrile) (SAN), poly(4-vinylphenol) (PVPh), and poly(vinylidene fluoride) (PVDF), in order to improve the water-resistance of PEOX. The blends' water resistance properties are evaluated by the contact angle, solubility, moisture absorption, and mechanical strength in a wet environment. The results show that the water resistance and the adhesion strength of PEOX in a wet environment are dramatically enhanced by polymer blending. The blend with 30 wt% PVPh demonstrates excellent performances in transparency and water-resistant abilities. It is found that the stable hydrogen bonding within the blend plays an important role in hydrophobic modification. The PVPh/PEOX blend can be applied as a new type of transparent coating or adhesive with enhanced water-resistant properties in a wet environment.Item TiO2 enhanced ultraviolet detection based on a graphene/Si Schottky diode(Royal Society of Chemistry., 2015-03-11) Zhu, Miao; Zhang, Li; Li, Xinming; He, Yijia; Li, Xiao; Guo, Fengmei; Zang, Xiaobei; Wang, Kunlin; Xie, Dan; Li, Xuanhua; Wei, Bingqing; Zhu, Hongwei; Miao Zhu, Li Zhang, Xinming Li, Yijia He, Xiao Li, Fengmei Guo, Xiaobei Zang, Kunlin Wang, Dan Xie, Xuanhua Li, Bingqing Wei and Hongwei Zhu; Wei, BingqingGraphene/Si has been proved to form a quality Schottky junction with high photoelectric conversion efficiency at AM 1.5. However, for the ultraviolet portion of the incident light, the photoelectric performance will degrade significantly due to severe absorption and recombination at the front surface. Herein, to realize enhanced ultraviolet detection with a graphene/Si diode, TiO2 nanoparticles (NPs, 3–5 nm) are synthesized and spin-coated on the graphene surface to improve the photoresponse in the ultraviolet region. According to our results, the conversion efficiency of the graphene/Si diode at 420 nm and 350 nm increases by 72.7% and 100% respectively with TiO2 coating. Then C−2–V measurements of both TiO2 and graphene/Si diode are performed to analyze the electronic band structure of the TiO2/graphene/Si system, based on which we finally present the enhancement mechanism of photodetection using TiO2 NPs.