Khulud Almasabi1
KAUST1
The challenge of growing perovskite single crystals in suitable configurations for efficient photovoltaic devices has severely hindered their exploration as solar cell materials, in spite of their potential to advance perovskite solar cell technology owing to their excellent optoelectronic properties and lower defect densities. While polycrystalline films can be deposited on myriad substrates, perovskite single crystals suitable for high-efficiency devices have only been illustrated on hydrophobic hole transport layers (HTLs, e.g., poly(triaryl amine) (PTAA)), which has restricted the development in both device efficiency and stability. In this work, we report the growth of mixed-cations FA<sub>0.6</sub>MA<sub>0.4</sub>PbI<sub>3 </sub>perovskite single crystals on a hydrophilic self-assembled monolayer (SAM, [2-(3,6-dimethoxy-9H-carbazol-9-yl) ethyl]phosphonic acid), (MeO-2PACz)) HTL surface. Solar cells constructed with SAM MeO-2PACz exhibit improved mechanical adhesion, operational stability, and a record efficiency of 23.1% for single-crystal perovskite solar cells.