Enhanced hydrothermal heterogeneous deposition with surfactant additives for efficient Sb2S3 solar cells

Antimony sulfide (Sb2S3) has great potential as a promising wide–bandgap, low–cost, low–toxicity, and stable photovoltaic material for next–generation indoor and tandem photovoltaic applications. This article reports that there are competitive chemical reaction mechanisms during hydrothermal preparation of Sb2S3, and we present an effective strategy to control these mechanisms using the anionic surfactant sodium dodecyl sulfate (SDS) as a reaction additive. We found that the SDS additive significantly enhances the hydrothermal heterogeneous reaction path and thus improves the quality of the Sb2S3 absorber by shifting the balance between homogeneous and heterogeneous reactions. An efficiency of 6.84% under standard AM1.5 illumination irradiance is achieved. The SDS–optimized Sb2S3 solar cells also show remarkably high indoor photovoltaic performance. An efficiency as high as 16.37% is reported under indoor illumination by a 1000 lx white light LED source. This result indicates the excellent prospects of Sb2S3 in a broad range of photovoltaic applications.