Rapid preparation of conductive transparent films via solution printing of graphene precursor

We report convenient approaches to obtain large-area conductive graphene films via a solution printing method. Spray deposition and blade coating were used to prepare graphene films as the representative printing methods. Some parameters, such as the reduction temperatures, pre-treatments of precursor, printing speeds and etc., were investigated to optimize the conductivities of samples. The prepared graphene oxide (GO) and reduced graphene oxide (rGO) films were characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, UV-vis spectroscopy and X-ray photoelectron spectroscopy. The results indicate that films prepared by spraying GO-hydrazine dispersion and blade coating GO solution possess good performance, including decent photoelectric property, crystal structure and a high carbon to oxygen ratio. Sheet resistances of 3.4 kΩ/sq. (spray coating) and 3.6 kΩ/sq. (blade coating) at around 75% transparency were obtained by measuring the printed conductive films. Moreover, the as-made rGO films were used as the transparent conductive layer for planar perovskite solar cells and achieved an efficiency of 3.38%.