Back-contact structures for optoelectronic devices: Applications and perspectives

Interdigitated back contact (IBC) structures formed by integrating two functional materials of opposite polarity on the rear side of device have attracted a significant attention for optoelectronic device design. Currently, this type of IBC design has been widely developed with a variety of applications in the photovoltaic (PV) community and associated fields. In terms of PV devices, the IBC designs can eliminate the need for a front electrode, endowing a potential in high power conversion efficiency. Moreover, by opening the front surface on IBC structures provides a platform for further designs, which enables us to realize a series of derived applications. This review summarizes the recent progress in IBC based PV devices, including c-Si solar cells (SCs), perovskite SCs, and perovskite/c-Si tandem SCs. Furthermore, the focus herein is focused on the latest advances in the specific applications in the studies of photon recycling, and in-situ/in-operando measurements of photoelectric properties. Finally, a perspective into the remaining challenges and future opportunities to accelerate the practical applications of IBC devices is highlighted.