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Solar cells devices based on inorganic/polymer heterojunction can be a possible solution to harvest solar energy and convert to electric energy with high efficiency through a cost-effective fabrication. The solution-process method can be easily used to produce large area devices. Moreover, due to the intrinsic different charge separation, diffusion or recombination in various semiconductors, the interfaces between each component may strongly influence the inorganic/polymer heterojunction performance. Here we prepared a n-type Ag 3 CuS 2 (Eg = 1.25 eV) nanostructured film through a room-temperature element reaction process, which was confirmed as direct bandgap semiconductor through density function theory simulation. This Ag 3 CuS 2 film was spin-coated with an organic semiconducting poly(3-hexythiophene) (P3HT) or polythieno[3,4-b]-thiophene-co-benzodithiophene (PTB7) film, which formed an inorganic/polymer heterojunction. After constructing it to a solar cell device, the power conversion efficiencies of 0.79% and 0.31% were achieved with simulated solar illumination on Ag 3 CuS 2 /P3HT and Ag 3 CuS 2 /PTB7, respectively. A possible mechanism was discussed and we showed the charge separation at interface of inorganic and polymer semiconductors played an important role. [ABSTRACT FROM AUTHOR]

• CdS under-layer reduces the recombination at Ag 2 S/FTO interface. • Photoinduced charge carrier dynamics of FTO/CdS/Ag 2 S has been studied. • CdS under-layer raise 52% PCE of Ag 2 S solar cell. [Display omitted] The recombination of photoinduced charge carriers is detrimental to the photovoltaic performance of solar cells. In this work, we used CdS as an under-layer to reduce the recombination of photoinduced charge carriers at the Ag 2 S/FTO (F-doped SnO 2) interface. The CdS under-layer was deposited onto an FTO substrate using a facile chemical bath deposition (CBD) method. By controlling the thickness of the CdS film between Ag 2 S and FTO, the recombination of photoinduced charge carriers was successfully suppressed. The effect of the CdS under-layer on the charge carrier recombination was carefully evaluated by transient surface photovoltage (TSPV) measurements, electrochemical impedance spectroscopy (EIS) and a photoelectrochemical method. The power conversion efficiency (PCE) of solar cell devices with a 40 nm CdS under-layer is 1.16%, which is ~52% enhancement compared to those of FTO/Ag 2 S-based solar cell devices. Our work may provide a useful strategy to suppress photoinduced charge carrier recombination at the electrode and absorber semiconductor interface. [ABSTRACT FROM AUTHOR]