Effect of interface incorporation of cadmium nanocrystallites on the photovoltaic performance of solar cells based on CdS/Si multi-interface nanoheterojunction

•Solar cells based on CdS/Si multi-interface nanoheterojunctions are prepared.•Cd nanocrystallites (nc-Cd) are incorporated naturally into the heterojunction interface.•The cell energy conversion efficiency is greatly promoted because of nc-Cd incorporation.

A non-planar and multi-interface CdS/Si nanoheterojunction was prepared by growing CdS nanocrystallites (nc-CdS) onto silicon nanoporous pillar array (Si-NPA) using a chemical bath deposition (CBD) method. Utilizing the surface reducibility of Si-NPA, small quantities of Cd nanocrystallites (nc-Cd) were incorporated naturally into the CdS–Si interface during the CBD process. Solar cells with a device construction of ITO/CdS/Si-NPA/Al were prepared based on CdS/Si-NPA and their photovoltaic performances, including open circuit voltage, short circuit current density, external quantum efficiency and energy conversion efficiency, were measured under simulated AM 1.5 G illumination. Compared with CdS/Si-NPA cells without nc-Cd incorporation, an energy conversion efficiency promotion by two orders of magnitude was achieved, which was ascribed to the reduction of the series resistance resulted from the nc-Cd incorporation at the interface. Our results show that the incorporation of nc-Cd at CdS–Si interface might be an effective path for obtaining high-efficiency solar cells based on CdS/Si multi-interface nanoheterojunctions.

Graphical abstractA multi-interface CdS/Si nanoheterojunction is prepared through growing CdS nanocrystallites (nc-CdS) onto silicon nanoporous pillar array (Si-NPA) by a chemical bath deposition method. Utilizing the surface reducibility of Si-NPA, Cd nanocrystallites (nc-Cd) are incorporated naturally into CdS–Si interface. The experimental results show that the interface incorporation of nc-Cd can promoted greatly the energy conversion efficiency of the solar cells based on CdS/Si-NPA.Figure optionsDownload full-size imageDownload as PowerPoint slide