Modulating chemical composition and work function of suspended reduced graphene oxide membranes through electrochemical reduction. (15th November 2021)

• Record Type: Journal Article
• Authors: Rodriguez, Jan Sebastian Dominic; Ohigashi, Takuji; Lee, Chi-Cheng; Tsai, Meng-Hsuan; Yang, Chueh-Cheng; Wang, Chia-Hsin; Chen, Chi; Pong, Way-Faung; Chiu, Hsiang-Chih; Chuang, Cheng-Hao
• Is Part Of: Carbon. Volume 185(2021)
• Page Start: 410
• Page End: 418
• Publication Date: 2021-11-15
• Subjects: Scanning transmission X-ray microscopy -- Kevin probe force microscopy -- Density function theory -- Reduced graphene oxide -- Work function -- Membrane -- Oxygen functional group; Carbon -- Periodicals; Carbone -- Périodiques; Koolstof; Toepassingen; Electronic journals; 546.681
• DOI: 10.1016/j.carbon.2021.09.015
• Languages: English
• ISSNs: 0008-6223

Abstract

Abstract: Electrochemical reduction in aqueous graphene oxide (GO) dispersion has emerged as an alternative route to producing a reduced GO (rGO) membrane on Au mesh. Under scanning electron microscopy, an interesting pattern formed by distinct differences was discovered from the deoxidization evolution. Scanning transmission X-ray microscopy shows the chemical composition coordination mixing of C–OH, C–O–C, HO–CO, and CO bonds at nanoscale resolution. The electrochemical reduction of C–OH, new bonding of C–O–C, and structure recovery of CC were obtained from GO transformation into the rGO membrane. In Kelvin probe force microscopy, the same pattern of rGO was also observed for the diversity of work functions ranging from 5.55 to 5.70 eV compared with the uniform distribution of GO of 5.78 eV. Density functional theory calculations predicted that the work function variation originated from the dependence of O atom number and functional group species. A high (low) diversity in work function values was ascribed to the C–O–C (HO–CO) bond even with increasing oxygen numbers, accounting for the peak variation. Controlling the work function holds great significance for photovoltaic behavior and band alignment in photoelectric devices. Thus, growing large-area rGO membranes offers a new route to obtaining membranes for applications requiring transparent materials. Graphical abstract: Image 1 Highlights: Large-area and suspended membrane synthesized from the aqueous graphene oxide dispersion. Electrochemical reduction of C–OH, interlayer connection of C–O–C, lattice reconstruct of C=C bond after the electrochemical reduction. Work function variation studied by kelvin probe force microscopy and density function theory calculation. Chemical composition and work function modulation for the transparent optical and electronics devices.