Towards the fabrication of third generation solar cells on amorphous, flexible and transparent substrates with well-ordered and disordered Si-nanowires/pillars

Si Nanowires (NWs) are typically synthesized on limited substrates that lack essential characteristics, such as mechanical flexibility and optical transparency. Most of the synthesis processes are also costly and inhibit widespread applications enabled by NWs. Throughout this study, therefore, we have shown that ordered and disordered single crystalline silicon nanowires can be grown and transferred from Si wafer to a broad range of foreign substrates while maintaining their original order on the mother substrates. Vertically-aligned Si NWs have been successfully transferred to Ag-pre-coated glasses, transparent-conductive-oxides and metal foils that ensure ohmic contacts between Si NWs and the transferred substrates, which are critical for scalable manufacturing of electronics and opto-electronic devices. This strategy presents an opportunity to develop lowcost device manufacturing with highly crystalline semiconductor materials, and is a critical leap towards the next generation high performance core-shell Si-NWs solar cells. In order to demonstrate devices based on the transferred NWs, the NWs are coated with a thin layer of CZTS to fabricate a third generation solar cell. The devices were characterized and exhibited the highest power conversion efficiency of 1.31% reported to date, for such transferred NWs and material combinations.