| 초록 |
Recently, organic-inorganic hybrid perovskite solar cells have been studied with giant interest due to high photovoltaic efficiency (~20%) with strong light absorption since 2012. Many studies on perovskite solar cells have performed with various focuses on electron transfer, interface phenomenon, bandgap engineering, humidity control and light scattering for improvement of photovoltaic performance and long-term stability. In particular, recent one study on perovskite solar cells illustrated importance of contact between perovskite layer (PL) and counter electrode (CE) because the electrical resistance at this interface is dominantly related with poor photovoltaic efficiency of perovskite solar cells. We also realized that the interface between PL and CE is really critical for high photovoltaic efficiency and long-term stability because electrical contact, recombination, moisture absorption, light scattering and more factors can be determined at that interface. In this study, we investigated roughness effect of PL by additional perovskite coating with variable concentration on PL. Scanning electron microscopy (SEM), X-ray diffraction patterns (XRD), X-ray photoelectron spectroscopy (XPS) and contact angle characterizations were performed to confirm roughness, particle size, crystal structure and hydrophilicity of perovskite layers. Finally, perovskite solar cell with smooth surface of PL exhibited high photovoltaic efficiency and better long-term stability by enhancement of electrical contact and moisture stability, respectively. Our experiment for fabrication of CH3NH3PI3/Carbon electrode films were conducted under ambient condition at room temperature without a vacuum and inert atmosphere. |
