Improved Stability in Perovskite Solar Cells by Solution-Processed Fluorocarbon Passivation

Since the first demonstration of perovskite solar cells (PSCs) was reported, there have been many efforts to improve the stability by investigating the degradation mechanism. This is because PSCs are considerably vulnerable to the moisture in air. In this letter, we demonstrate highly stable and robust PSCs employing the stack structure by solution-processed fluorocarbon films as a passivation layer, Teflon-AF which exhibits high hydrophobicity for efficient removal of water molecules. Material characterization using x-ray diffraction proves that the improved stability of PSCs under harsh humidity (70%) results from the effective and practical passivation that suppresses the chemical interaction of perovskite films with water molecules. It must be noted that the proposed passivation can be realized by simple spin-coating methods at low temperature of 70 degrees C, which can open up a promising route to raise the technological interest in the process cost and temperature.