Fig. 1. Schematic diagram of the prepared LED device: (a) Graphene transparent electrode LED I; (b) graphene/ITO composite transparent electrode LED II; (c) optical micrograph of wet transfer graphene (graphene on the left and ITO on the right).制备的LED器件的结构示意图　(a)石墨烯透明电极LED I; (b)石墨烯/ITO复合透明电极LED II; (c)湿法转移石墨烯的光学显微镜图(左侧阴影部分为石墨烯, 右侧为ITO)

Fig. 2. Dot circular transmission line model (dot-CTLM): (a) Model diagram; (b) test sample.圆点传输线模型　(a)模型示意图; (b)测试样品图

Fig. 3. I-V curves of LED I and LED II under high current. 大电流下, LED I与LED II的I-V测试曲线

Fig. 4. Optical graphs of LEDs: (a) LED I; (b) LED II.LED发光光学照片　(a) LED I; (b) LED II

Fig. 5. Spectrum of LED I and LED II. Inset shows the curves of the FWHM with currentLED I与LED II的光谱图(内插图为半高宽随电流的变化)

Fig. 6. Comparison of radiant flux of LED I and LED IILED I与LED II辐射通量随电流变化对比图