Ultrathin flexible planar crystalline-silicon/polymer hybrid solar cell with 5.68% efficiency by effective passivation

Abstract Ultrathin silicon based solar cells provide a viable way to reduce the material usage and diversify their applications. However, complex light-trapping structures are always needed to be fabricated to enhance light absorption, which will lead to exacerbation of carrier collection and expensive fabrication cost. Here, we report very simple planar flexible crystalline silicon-polymer hybrid solar cell with thickness about 18 μm, whose power conversion efficiency (PCE) reaches 5.68%. By introducing the amorphous silicon layer to passivate the Silicon/Polymer interface in our device, with accuracy control of the thickness of 2 nm to balance the passivation effect and the deterioration of internal electric field, the short current density reaches 83.0% of the theoretical limit. Additionally, we found that the average PCE of solar cells passivated by such technology is 5.8% and 7.1% enhanced compared with those without passivation (H-terminated) and passivated by native oxide approaches. The simple device structure provided in this study has great practicability, and the passivation processes can be duplicated for other silicon based photovoltaic devices.