Growth of high-quality graphene and its applications on hybrid organic- inorganic solar cells
|關鍵字:||混合型太陽電池;石墨烯;hybrid solar cells;graphene|
In this thesis, we successfully use tubular copper foil to grow high-quality single-crystalline graphene. In order to scale up for device applications, we have further optimized and improved the growth parameters. First, we use graphite as blockers to increase the probability of gas collisions on to the copper foil. We obtain high-quality graphene but the uniformity is not as ideal. Next, we prepare an oxide layer on the copper foil with surface cleaning techniques, which successfully increase the grain size of graphene to about tens of microns. Finally, we change the growth time and gas flow rate, where low rate and long growth time result in high-quality graphene of which the ratio of Raman signal 2D/G peak is 3 with very good uniformity. Moreover, we transfer this high-quality graphene onto a PET film as the transparent conductive electrode for hybrid organic-inorganic solar cells. According to the simulation, we can see that later carrier conduction of PEDOT:PSS is limited by the doping concentration as well as the conductivity. Therefore, we have employed graphene transparent conductive film to help collect and transport carriers. In the silicon base hybrid solar cells, the two-layer-graphene transparent conductive film give rise to the best device performance. The power conversion efficiency of device is 8.95 %, corresponding to an enhancement factor of 53.5%. In the GaAs base hybrid solar cells, we use single-layer- graphene transparent conductive film to optimize the cells. The power conversion efficiency of device is 8.60 %, corresponding to enhancement of 25.5%.