Ambient Stable Perovskite Solar Cells through Trifluoro Acetic Acid-Mediated Multifunctional Anchoring

The functional groups of any organic materials play a key role in improving the efficiency and stability of hybrid perovskite solar cells (PSCs). This has led to the use of multifunctional organic molecules for the passivation of perovskites. Herein, trifluoro acetic acid (TFAA) has been reported as an additive for the efficient passivation of perovskite for use in PSC applications. TFAA interacts with perovskites to passivate the defect states and enhance the device performance. The power conversion efficiency (PCE) of the champion device was found to be 20.10%, which improved from 15.08% for the control device without any TFAA. This enhancement resulted due to efficient perovskite passivation, improved crystallinity, and film-forming ability which was confirmed by various studies like density functional theory, Fourier transform infrared spectroscopy, ¹H nuclear magnetic resonance, field emission scanning electron microscopy, atomic force microscopy, and X-ray diffraction. The decrease in defects and trap density was proved by UV-vis, photoluminescence, electrochemical impedance spectroscopy, and other relevant analyses, resulting in better charge generation, reduced recombination, and better charge transport. The fluorinated additive improves the hydrophobicity of the perovskite layer and boosts the ambient stability of the device.