Interface Control Research Center, Future Convergence Research Division, Korea Institute of Science and Technology, Hwarangro 14 gil 5, Seoul, Korea.
Nat Nanotechnol. 2012 May 27;7(7):465-71. doi: 10.1038/nnano.2012.71.
Hybrid nanostructures combining inorganic materials and graphene are being developed for applications such as fuel cells, batteries, photovoltaics and sensors. However, the absence of a bandgap in graphene has restricted the electrical and optical characteristics of these hybrids, particularly their emissive properties. Here, we use a simple solution method to prepare emissive hybrid quantum dots consisting of a ZnO core wrapped in a shell of single-layer graphene. We then use these quantum dots to make a white-light-emitting diode with a brightness of 798 cd m(-2). The strain introduced by curvature opens an electronic bandgap of 250 meV in the graphene, and two additional blue emission peaks are observed in the luminescent spectrum of the quantum dot. Density functional theory calculations reveal that these additional peaks result from a splitting of the lowest unoccupied orbitals of the graphene into three orbitals with distinct energy levels. White emission is achieved by combining the quantum dots with other emissive materials in a multilayer light-emitting diode.
我们使用一种简单的溶液法制备了由 ZnO 核和单层石墨烯壳组成的发光混合量子点，然后用这些量子点制作出亮度为 798 cd/m²的白光发光二极管。由曲率引起的应变在石墨烯中产生了 250 meV 的能带隙，并且在量子点的发光光谱中观察到两个额外的蓝色发射峰。密度泛函理论计算表明，这些额外的峰源于石墨烯的最低未占据轨道分裂成三个具有不同能级的轨道。通过在多层发光二极管中混合其他发光材料，实现了白光发射。
