Solution-processed SnO2 interfacial layer for highly efficient Sb2Se3 thin film solar cells.

Antimony selenide (Sb 2 Se 3) thin film solar cells have gained worldwide intense research owing to their suitable bandgap, high absorption coefficient, benign grain boundaries, earth-abundant element constituents and low fabrication cost. It is extremely important to investigate the interface passivation and minimize the carrier recombination to realize high-efficiency Sb 2 Se 3 solar cells. Very little is known, however, about the carrier recombination mechanisms at the interfaces of Sb 2 Se 3 solar cells. Herein, we show that a novel solution-processed SnO 2 layer (∼12 nm) incorporated into Sb 2 Se 3 thin film solar cells results in high power conversion efficiency of 7.5%, namely, an improvement of 39% relative to that of the solar cell without SnO 2 interfacial layer. Furthermore, the open-circuit voltage (V oc) is the highest ever reported for Sb 2 Se 3 solar cells. These improvements benefit from the better preferred [221] orientation, less bulk and interfacial defects in the Sb 2 Se 3 absorbers, and relatively ideal heterointerfaces due to the SnO 2 passivation. This work opens up new routes for the critical importance of interfacial control in Sb 2 Se 3 solar cells, which could be extended to other emerging low-dimensional thin film solar cells. Image 1 • A simple VTD technique is developed for the production of Sb 2 Se 3 absorbers. • Sb 2 Se 3 solar cell with a SnO 2 layer obtains high power conversion efficiency of 7.5%. • SnO 2 layer improves the properties of Sb 2 Se 3 absorbers. • An amorphous layer at interface is found, which can be inhibited by SnO 2 layers. [ABSTRACT FROM AUTHOR]