Tuning the crystallization process of perovskite active layer using a functionalized graphene oxide for enhanced photovoltaic performance

摘要

The nonoptimized morphology of the active layer has been a major bottleneck for enhancing the performance of perovskite photovoltaic (PV) devices. To address this challenge, the influence of graphene oxide (GO) additive on the device performance was studied using a two-step sequential deposition technique. Depending on the chlorine-functionalized GO (Cl-GO) amount, we observe dramatic changes in the morphology (e.g., grains, grain boundaries, and crystallite size) of the perovskite layer. Resultantly, we find that the optimized amount of Cl-GO is 5.0 volume % in the perovskite precursor PbI_2 solution, which affords the solar-to-electrical power conversion efficiency (PCE) of 15.14% in PV devices with configuration of fluorine-doped tin oxide (FTO)/NiO_xCH_3NH_3PbI_3+Cl-O/[6,6]-phenyl-C_(61)butyric acid methyl ester (PC_(61)BM)/ bathocuproine (BCP)/Ag. Importantly, this PCE is about 18% enhancement compared to the PCE of 12.81% in the absence of Cl-GO. Hence, our work provides an insight for fabricating high-efficient perovskite solar cells based on the relationship between additive processing and morphology, affecting device performance.