Maiti R, Midya A, Narayana C, Ray S K
Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur-721302, India.
Nanotechnology. 2014 Dec 12;25(49):495704. doi: 10.1088/0957-4484/25/49/495704. Epub 2014 Nov 21.
The modification of individual oxygen functional groups and the resultant optical properties of a graphene oxide suspension were investigated using a controlled photothermal reduction by infrared irradiation. The evolution of the structural and optical characteristics of GO suspensions was obtained from Raman spectra, x-ray photoelectron spectroscopy, optical absorption, and steady state and time-resolved photoluminescence spectroscopy. The results suggest the gradual restoration of sp(2) clusters within the sp(3) matrix with an increase of the reduction time and power density. The yellow-red emission (∼610 nm) originated from the defect-assisted localized states in GO due to epoxy/hydroxyl (C-O/-OH) functional groups and that of the blue emission (∼500 nm) was ascribed to the carbonyl (C=O)-assisted localized electronic states. With an increase in the reduction time and IR power density, the intensity of the yellow-red emission was found to decrease, with the blue emission being prominent. These experimental findings open up a new dimension for controlling the optical absorption and emission properties of graphene oxide by tailoring the oxygen functional groups, which may lead to the potential application of graphene-based optoelectronic devices.
利用红外辐射控制光热还原法，研究了氧化石墨烯悬浮液中单个氧官能团的修饰及其产生的光学性质。通过拉曼光谱、X射线光电子能谱、光吸收以及稳态和时间分辨光致发光光谱，获得了氧化石墨烯悬浮液结构和光学特性的演变情况。结果表明，随着还原时间和功率密度的增加，sp(3) 基质中的sp(2) 簇逐渐恢复。黄红色发射（610 nm）源于氧化石墨烯中由环氧/羟基（C-O/-OH）官能团引起的缺陷辅助局域态，蓝色发射（500 nm）归因于羰基（C=O）辅助的局域电子态。随着还原时间和红外功率密度的增加，发现黄红色发射的强度降低，蓝色发射突出。这些实验结果为通过调整氧官能团来控制氧化石墨烯的光吸收和发射特性开辟了一个新的维度，这可能会导致基于石墨烯的光电器件的潜在应用。
