Interfacial engineering by using self-assembled monolayer in mesoporous perovskite solar cell

A self-assembled monolayer of 4-aminobenzoic acid (PABA) is prepared on the top of a mesoporous TiO₂ electron transfer layer. Through the full characterization of PABA-SAM modified TiO₂ and the above-prepared perovskite layer with Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), contact angle and photoluminescence, it was clear that the introduction of the SAM improved the interfacial compatibility and therefore the quality of the perovskite, thus leading to fewer traps, better carrier transport and good energy matching between the TiO₂ layer and the perovskite layer. The power conversion efficiency (PCE) of the perovskite device with interfacial modification was enhanced to 10.58% compared with that of the device without SAM.