An effective method to directly produce high-quality graphene nanowalls (GNWs) on quartz substrates was demonstrated using an advanced self-assembled ratio-frequency plasma-enhanced horizontal tube furnace deposition system under different growth times from 60[Formula: see text]s to 150[Formula: see text]s at a substrate temperature of 850[Formula: see text]C without using any catalyst. The synthesized well-connected three-dimensional GNWs feature outstanding electrical and optical performance: the sheet resistance varies from 1053 [Formula: see text]/[Formula: see text] to 342 [Formula: see text]/[Formula: see text], while the corresponding transmittance ranges from 90.4% to 67.8% at a wavelength of 550[Formula: see text]nm under different growth times. We have also demonstrated that GNWs can be used as transparent conductive electrodes for perovskite solar cells. The highest photovoltaic conversion efficiency of 6.93% can be obtained for the GNWs deposited at a growth time of 120[Formula: see text]s. Hence, our study paves a new way of using GNWs as transparent conductive electrodes in perovskite solar cells.