Improved Sb2S3/TiO2 Nanoarray Heterojunction Solar Cells by an Insulating Hole-Selective Tunneling Layer

Photovoltaic technology for sustainable energy production on a large scale is mainly limited by the lack of solar cells with efficient, stable, and lowcost characteristics. Antimony trisulfide (Sb2S3) has attracted intensive attention as a potential photon-absorbing material for efficient and stable inorganic heterojunction solar cells due to its feasible preparation. Here, a hole-selective tunneling interfacial engineering method is developed to improve the performance of solar cells based on solution-processed Sb2S3/TiO2 nanoarray heterojunction (Sb2S3/TiO2-NHJ), for which an ultrathin poly(methyl methacrylate) (PMMA) film deposited into Sb2S3/TiO2-NHJ serves as the insulating hole-selective tunneling interfacial layer in the solar cells. It is found that the hole-selective tunneling PMMA interfacial layer effectively blocks the channels for interfacial recombination of photogenerated charge carriers, and the origins for the PMMA interfacial layer to boost the overall device performance get elucidated.