Photovoltaic Heterojunctions of Fullerenes with MoS2 and WS2 Monolayers

• Published in: The journal of physical chemistry letters 2014-04, Vol.5 (8), p.1445-1449
• Main Authors: Gan, Li-Yong, Zhang, Qingyun, Cheng, Yingchun, Schwingenschlögl, Udo
• Format: Article
• Language: English
• Subjects: Surfaces, Interfaces, Porous Materials, and Catalysis
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/jz500344s

First-principles calculations are performed to explore the geometry, bonding, and electronic structures of six ultrathin photovoltaic heterostructures consisting of pristine and B- or N-doped fullerenes and MoS2 or WS2 monolayers. The fullerenes prefer to be attached with a hexagon parallel to the monolayer, where B and N favor proximity to the monolayer. The main electronic properties of the subsystems stay intact, suggesting weak interfacial interaction. Both the C60/MoS2 and C60/WS2 systems show type-II band alignments. However, the built-in potential in the former case is too small to effectively drive electron–hole separation across the interface, whereas the latter system is predicted to show good photovoltaic performance. Unfortunately, B and N doping destroys the type-II band alignment on MoS2 and preserves it only in one spin channel on WS2, which is unsuitable for excitonic solar cells. Our results suggest that the C60/WS2 system is highly promising for excitonic solar cells.