Dye Sensitization of Titania Compact Layer for Efficient and Stable Perovskite Solar Cells

In this work, the dye-sensitization approach was used to optimize the compact layer/perovskite interface in planar perovskite solar cells (PSCs). The chemisorption of the triphenylamine-based metal-free organic (E)-3-(5-(4-(bis(2′,4′-dibutoxy-[1,1′-biphenyl]-4yl)amino)phenyl)thiophen-2-yl)-2-cyanoacrylic acid (D35) sensitizer via a bidentate anchor group on the titania surface resulted in both enhanced electron transfer and controlled growth of the top MAPbI3 perovskite layer. This modification led to planar PSC devices presenting significantly improved performance and increased stability. Using the Spiro-OMeTAD molecular hole conductor, stabilized output power conversion efficiencies (PCEs) of 13% were obtained for cells with titania sensitization, clearly outperforming those of cells without D35. This investigation gives new insights into how the molecular engineering via dye sensitization of the functional interfaces affects the performance in PSCs.