Alexander Carl1 John Obayemi1 Martiale Zebaze Kana1 Winston Soboyejo1 Ronald Grimm1

1, Worcester Polytechnic Institute, Worcester, Massachusetts, United States

We investigated synthetic strategies for the functionalization of Si(111) surfaces with organic species containing moieties were covalently bonded to silicon and ionically coupled to solar-relevant perovskite thin films. X-ray photoelectron spectroscopy and infrared reflection absorption spectroscopy characterized the bonding and packing of covalently bound molecules to the silicon surface, while microwave photoconductivity experiments quantifed the interfacial defect density due to surface oxides. Atomic force microscopy (AFM) quantified perovskite–silicon adhesion, and nonaqueous photoelectrochemistry explored solar-energy-conversion performance. Adhesion forces/interactions between the perovskite and the organic-functionalized films were comparable to the interaction between the perovskite and native-oxide silicon surface. Photoelectrochemistry of perovskite thin films on organic-functionalized n+-Si showed significantly higher Voc than n+-Si with a native oxide when in contact with a nonaqueous ferrocene+/0 redox couple. We discuss the present results in the context of utilizing molecular organic recognition to attach perovskites to silicon utilizing organic linkers so as to inexpensively modify silicon for future tandem-junction photovoltaics.