Efficient coaxial n-i-p heterojunction Sb₂S₃ solar cells

Abstract Sb2S3 is a kind of emerging light harvesting material for solar cell applications, where both planar and nanostructured configurations are of great interests in the device investigations. This work conducts a comparative study on heterojunction configuration of Sb2S3 solar cells with regard to different CdS substrates. By controlling the hydrothermal durations of Sb2S3 film, the CdS nanorod enables the fabrication of coaxial n-i-p heterojunction Sb2S3 solar cells. It is demonstrated that coaxial heterojunction can effectively improve carrier transport compared with planar heterojunction, leading to the fill factor increasing from 51.3% to 62.7% with regard to different degree of pore filling. Mechanism investigations suggest that both deep-level defect type and defect density in coaxial heterojunction device are significantly reduced, which further reduces carrier recombination in Sb2S3 film, clearly manifesting that the coaxial heterojunction configuration reduces the series resistance and enables efficient carrier transport. In addition, the coaxial heterojunction device presents a remarkably improved stability compared with planar heterojunction device. The research offers a fundamental guideline for the fabrication of efficient antimony chalcogenide solar cells.